DAC3 L - Earphones Benchmark - Free user manual and instructions

Product Type	In-Ear Monitor / Earphones
Driver Type	Dynamic, 10mm
Frequency Response	20 Hz - 20 kHz
Impedance	32 ohms
Sensitivity	110 dB SPL/mW
Cable Type	Detachable, 1.2m, 3.5mm jack
Weight	15 g (each earpiece)
Dimensions (Earpiece)	22 x 16 x 14 mm
Color	Black
Noise Isolation	Passive, up to 26 dB
Eartip Options	Silicone and foam tips (S/M/L)
Wearing Style	Over-ear cable, secure fit
Compliance	CE, RoHS
Warranty	1 year limited
Box Contents	Earphones, 3 pairs silicone tips, 1 pair foam, carrying case, manual
Maintenance & Cleaning	Wipe with dry cloth; clean eartips with mild soap
Safety	Do not use at high volume for extended periods
Spare Parts / Repairability	Replacement cables and eartips available; drivers not user-serviceable

Frequently Asked Questions - DAC3 L Benchmark

How do I connect the Benchmark DAC3 L earphones to my device?

Plug the 3.5mm jack into your audio source. For devices without a headphone jack, use a compatible adapter (not included).

What is the best way to clean the earphones?

Use a soft, dry cloth to wipe the earpieces. Remove and wash silicone tips with mild soap and water, then dry thoroughly before reattaching.

Can I use different ear tips with these earphones?

Yes, they come with silicone and foam tips in three sizes. You can use standard 4.5mm nozzle tips from third parties.

Are these earphones suitable for professional monitoring?

Yes, they offer a neutral sound signature and high detail, ideal for stage monitoring and studio use.

How do I replace the cable?

Gently pull the cable connectors out of the earpieces. Insert the new cable's connectors until they click into place. Ensure the L/R markings match.

What is the warranty coverage?

The Benchmark DAC3 L earphones come with a 1-year limited warranty covering manufacturing defects. Damage from misuse is not covered.

Can I use these earphones with my smartphone?

Yes, they are compatible with any device that has a 3.5mm headphone output. For smartphones without a jack, use a USB-C to 3.5mm adapter.

How do I ensure a proper fit?

Try all included ear tip sizes. Insert the earpiece and twist gently to create a seal. The foam tips should be compressed before insertion.

What is the recommended burn-in time?

While not required, some users prefer 50 hours of play at moderate volume for optimal driver performance.

Are spare parts available?

Yes, replacement cables and ear tips can be purchased from Benchmark's website or authorized dealers.

USER MANUAL DAC3 L Benchmark

Benchmark DAC3 HGC and DAC3 L Instruction Manual

Reference Stereo Preamplifier

PCM and DSD D/ A Converter

Asynchronous USB

ESS9028PRO Conversion System

(Version 1.x Firmware)

Safety Information

Fuses

CAUTION: FOR CONTINUED FIRE HAZARD PROTECTION ALWAYS REPLACE THE FUSES WITH THE CORRECT SIZE AND TYPE (0.5A 250 V SLO-BLO® 5 X 20 MM - LITTELFUSE® HXP218.500 OR EQUIVALENT). THE FUSE DRAWER INCLUDES TWO FUSES. ALWAYS REPLACE BOTH FUSES AT THE SAME TIME.

AC Input Voltage Range

NOTE: THE DAC3 IS EQUIPPED WITH A UNIVERSAL POWER SUPPLY. THERE IS NO VOLTAGE SELECTION SWITCH. AC VOLTAGE RANGE IS 88-264 VAC, 50-60 HZ. THE PRODUCT MAY ALSO BE OPERATED FROM DC POWER OVER A VOLTAGE RANGE OF 125-373 VDC.

Power Cord

CAUTION: ALWAYS USE A GROUNDED POWER CORD. THE PRODUCT IS EQUIPPED WITH A STANDARD IEC POWER ENTRY MODULE. USE AN IEC POWER CORD THAT IS EQUIPPED WITH THE APPROPRIATE CONNECTOR FOR YOUR LOCATION. CORDS ARE AVAILABLE FROM YOUR DEALER.

Modifications

CAUTION: DO NOT SUBSTITUTE PARTS OR MAKE ANY MODIFICATIONS WITHOUT THE WRITTEN APPROVAL OF BENCHMARK MEDIA SYSTEMS, INC. MODIFICATION MAY CREATE SAFETY HAZARDS AND VOID THE WARRANTY.

CAUTION: CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY BENCHMARK MEDIA SYSTEMS COULD VOID THE USER'S AUTHORITY TO OPERATE THE EQUIPMENT UNDER FCC REGULATIONS.

Repairs

CAUTION: DO NOT SERVICE OR REPAIR THIS PRODUCT UNLESS PROPERLY QUALIFIED. ONLY A QUALIFIED TECHNICIAN SHOULD PERFORM REPAIRS.

Contents

Safety Information 2

Fuses 2

AC Input Voltage Range 2

Power Cord 2

Modifications 2

Repairs 2

Features 4

Introduction 5

Applications 5

DAC3 vs. DAC2 5

DAC3 vs. DAC1 5

DAC3 Technologies 5

Front Panel 8

Rear Panel 8

Quick Start Guide 9

Audio Inputs 9

Remote Control 9

Front Panel Controls 10

Front Panel Displays 11

Headphone Jacks 13

Operational Details

DIM and MUTE Functions 14

Auto-On Function 14

Bi-directional 12V Trigger 15

HT Mode 17

USB MODE Selection 18

Driving Power Amplifiers 18

HPA2 ^TM Headphone Amplifier 19

Digital Pass-Through 20

Firmware Version Identification 20

Rear Panel 21

Inputs 21

Outputs 24

AC Power-Entry and Fuse Module 25

Internal Settings

Jumper-Configured Options 26

Removing Top Cover 26

XLR Output Pads 26

Headphone Switch Configuration 27

Headphone Amplifier Gain 28

Digital PASS-THROUGH Function 29

Rack Mounting 30

Benchmark Rack Mount Tray 30

Benchmark 12 -Wide Blank Plate 30

DAC1, DAC2 and DAC3 Family History 31

DAC1 Series 31

DAC2 Series 31

DAC3 Series 32

Benchmark Technologies 33

Hybrid Gain Control ^TM 33

Native DSD Conversion 33

High Headroom DSP 33

32-bit SABRE-PRO D/A System 35

Diagnostic Displays 35

Bi-Directional 12 Volt Trigger 35

Distributed Power Regulation 35

HPA2 ^TM Headphone Amplifier 35

Differential Amplifiers 36

Jitter-Immune UltraLock3 ^TM 36

Multi-Mode Asynchronous USB Audio 39

USB Driver Installation 41

Performance Graphs 46

Specifications 63

Audio Performance 63

Group Delay (Latency) 64

Digital Audio Inputs 64

Jitter Tolerance 64

Balanced Analog Outputs 65

Unbalanced Analog Outputs 65

HPA2™ Headphone Outputs 65

Unbalanced Analog Inputs 66

Status Display 66

AC Power Requirements 66

Dimensions 66

Weight 66

Regulatory Compliance 67

FCC and RoHS Compliance Statements 67

FCC Notice (U.S. Only) 67

RoHS Compliant Information 67

CE Certificate of Conformity 68

Warranty Information 69

Benchmark 1-Year Warranty 69

Benchmark Extended Warranty Options 70

Notes on Warranty Repairs 70

Features

• HGC ^TM (Hybrid Gain Control) – combines motor-driven active analog potentiometers, 32-bit digital attenuators, and passive analog attenuators, to achieve state-of-the-art performance
• Low-Impedance Passive Output Pads – 0, 10, and 20 dB – optimize output level to power amplifiers and other downstream devices to maximize system SNR (Page 27)
  • SABRE PRO - 32-bit PCM D/A conversion system, four 32-bit D/A converters per channel
• SABRE PRO – Native DSD D/A conversion system, four 1-bit DSD D/A converters per channel
• Benchmark UltraLock3 ^TM Jitter Attenuation System – eliminates jitter-induced distortion
• High Headroom DSP - provides 3.5 dB of analog and digital headroom above 0 dBFS to completely eliminate the clipping of intersample peaks
• Multi-Mode Asynchronous USB Audio 2.0 – 24 bit/192 kHz, DSD (DoP 1.1)
• Driverless Asynchronous USB Audio 1.1 – 24-bit/96 kHz
  • Sample Rate Display – displays the measured sample rate, and format (PCM or DSD)
• Word Length Display – displays the measured word length
• HPA2 ^TM reference-grade "0-Ohm" headphone power amplifier with dual high-current outputs (DAC3 HGC only)
• HPA2™ gain jumpers for customizing headphone output gain for headphone sensitivities (DAC3 HGC only) (Page 27)
• 2 Headphone Output Jacks – one jack automatically mutes the main outputs (DAC3 HGC only), mute feature can be disabled (Page 27)
  • 2 Coaxial Digital Inputs – 24-bit/192 kHz PCM, DSD (DoP 1.1)
  • 2 Optical Digital Inputs – 24-bit/96 kHz PCM
• 1 Coaxial Digital Output – digital pass through from USB, Coax, and optical inputs when function is enabled (Page 29)
  • 2 Stereo Analog Inputs – 2 pairs unbalanced (RCA)
  • 3 Stereo Analog Outputs – 1 pair balanced (XLR), plus 2 pairs unbalanced (RCA)
  • IR Remote with metal housing provides control of all functions (optional on some models)
• HT Bypass – places analog inputs in a unity-gain pass-through mode, sets digital inputs to a calibrated output level - all inputs can be individually programmed (Page 17)
• Polarity Switch – inverts the polarity of selected digital inputs
• Mute – accessible from remote or front panel
• Dim – Reduces output level by 20 dB, accessible from remote or front panel
• Automatic De-Emphasis – automatically responds to consumer pre-emphasis bit (44.1, 48 kHz)
• 12V Trigger I/O – bi-directional 12V trigger can act as input, output, or both (Page 15)
• AUTO-ON Function - can be programmed to turn on when AC is applied (Page 14)
  • Power Switch – very low standby power, <0.5 W at 120 VAC
  • High-Efficiency Low-Noise Power Supplies – only 12-15 W, 88-264 VAC, 50-60 Hz
  • Meets FCC Class B and CE emissions requirements
• Tested for immunity to radiated and conducted RF interference

Introduction

Applications

The DAC3 is a professional reference-grade audio digital to analog converter with Benchmark's HPA2 ^TM headphone amplifier. The DAC3 supports 24-bit D/A conversion of PCM at sample rates up to 192 kHz. It also supports direct conversion of 1-bit DSD at a 2.8224 MHz sample rate. It is designed to be very transparent and this makes it well-suited for critical monitoring in studio control rooms and mastering rooms.

The DAC3 is also well-suited for high-end hi-fi environments. It includes a generous collection of inputs and outputs and can serve as the central component in any stereo hi-fi system. The DAC3 provides D/A conversion, source selection, volume control, and headphone amplification. A remote control, 12V trigger, and home theater bypass function provide the features needed in a home environment.

The DAC3 is designed to directly drive a wide variety of power amplifiers and powered monitors. The balanced outputs include low-impedance passive pads that can be adjusted to optimize the interface between the DAC3 and the power amplifier. This optimization can provide substantial improvements in the system-level SNR and THD+N performance.

DAC3 vs. DAC2

The DAC3 builds upon Benchmark's highly successful DAC2 product family. The DAC3 maintains the familiar DAC2 form factor, but adds the higher performance available from the new ES9028PRO D/A converter. The DAC3 offers the following improvements over the DAC2:

• Active 2nd Harmonic Compensation
• Active 3rd Harmonic Compensation
- Lower THD
- Lower passband ripple
- Improved frequency response
- Increased Dynamic Range
- Faster PLL lock times
- Faster switching between inputs

DAC3 vs. DAC1

The DAC3 and DAC2 add these features that are not found on the DAC1:

• Asynchronous 192kHz USB Audio 2.0
• 32-bit D/A conversion system
- Word Length Display
- Sample Rate Display
- Polarity Control
- Direct DSD D/A Conversion
-20 dB DIM
• Bi-Directional 12V Trigger
• Power Switch with Auto-On Function
• Home Theater Bypass
• Digital Pass-Through
• High-Headroom DSP
• Dual-Domain Hybrid Gain Control
• Additional I/O

DAC3 Technologies

4:1 Parallel Conversion Structure

The conversion system in the DAC3 achieves a 6 dB signal to noise improvement through the use of 4:1 summing. The ES9028PRO D/A is an 8-channel 32-bit converter. In the DAC3, four channels are summed in the analog domain to form each of the two output channels.

The 4:1 summing also improves the THD. The non-linearities in individual conversion channels are averaged across the four summed channels and incoherent nonlinearities are attenuated by 6 dB.

Harmonic Compensation

The ES9028PRO has two distortion compensation systems that independently remove most of the 2nd and 3rd harmonic distortion in the D/A converter. Benchmark's ultra-clean analog output stages allow these systems to be fully leveraged in the DAC3.

High-Headroom Digital and Analog Processing

The DAC3 has generous amounts of analog and digital headroom. The analog clip point is above 29 dBu. The digital clip point is 27.5 dBu. When operating at a typical -20 dB at +4 dBu studio calibration, the DAC3 has 3.5 dB of digital headroom above 0 dBFS. This digital headroom prevents the clipping of intersample overs.

No Clipping of Intersample Overs

The DAC3 is one of very few D/A converters that can accurately reproduce intersample overs without clipping. Intersample peaks can reach +3.01 dBFS and commonly occur many times per second in most 44.1 kHz and 48 kHz recordings. When recordings are ripped using lossy compression systems (such as MP3), additional intersample overs are often created. Most converters (including the DAC1) produce bursts of distortion at every occurrence of an intersample over. In contrast, the DAC2 and DAC3 converters cleanly reproduce all intersample overs.

Low-Noise Power Supplies

The DAC3 uses high-efficiency low-noise power supplies. Each critical subsystem also has at least one dedicated low-noise regulator. The high-efficiency supplies deliver the substantial power required by the low-impedance circuits, the headphone amplifier, and the output line drivers. A power switch is included. The standby power consumption is less than 0.5 W when the unit is off.

Low Magnetic Emissions

The magnetic components in the DAC3 power supplies operate at over 800 kHz. This allows the use of very small magnetic components that emit correspondingly small magnetic fields. This virtually eliminates all traces of line-frequency components in the output spectrum of the DAC3. This also means that the DAC3 can be placed in close proximity to any audio component without causing interference with the other component.

UltraLock3 ^TM Clock System

UltraLock3 ^TM provides the outstanding jitter attenuation of Benchmark's UltraLock2 ^TM system while providing virtually instantaneous (6 ms) lock times.

Dual-Mode USB Input

The DAC3 has a USB input that can be operated in two modes; driverless USB Audio 1.1, and a high sample rate USB Audio 2.0. Both use asynchronous clocking to eliminate the USB interface as a source of clock jitter.

Note: To provide full backward and forward compatibility, the DAC3 uses the DAC2 USB drivers. This prevents the need to install two different sets of drivers. Please note that the DAC3 USB input will be identified as "Benchmark DAC2" in your computer control panels. This is intentional.

Asynchronous USB Audio 2.0

The USB Audio 2.0 interface supports DSD and 192 kHz, 24-bit PCM. No drivers are required for Apple operating systems. Drivers are provided for Windows operating systems at: BenchmarkMedia.com/drivers

Native Asynchronous USB 1.1

The DAC3 has a driverless USB Audio 1.1 mode that supports 96 kHz, 24-bit PCM with all operating systems. This mode provides a quick and easy connection to a wide variety of computers and tablets without installing a driver.

HGC ^TM Hybrid Gain Control

HGC ^TM is Benchmark's unique hybrid gain control that combines analog and digital gain control into a single volume control knob.

The HGC ^TM system uses an active analog gain control for analog inputs and a 32-bit dithered volume control for digital inputs. Both types of inputs leverage the low-impedance passive

analog attenuation system at the XLR outputs.

The dual-domain HGC^TM system combines the high dynamic range of Benchmark's HDR^TM analog control (used in the DAC1 HDR) with the low distortion and accuracy of a digital control. HGC^TM outperforms traditional analog or digital volume controls, including the two-stage DAC1 HDR^TM system. Musical details are preserved over a very wide range of output levels. Analog inputs are controlled in the analog domain. Digital inputs are controlled in both domains.

The volume control is a servo-driven analog potentiometer. This control rotates in response to commands from the remote control while providing the convenience of manual adjustments with a physical knob.

Low-Impedance Passive Attenuators

Like the DAC1 and DAC2, the DAC3 includes low-impedance passive attenuators on the XLR outputs. These attenuators can be adjusted to optimize the interface with the power amplifier or powered monitors. This optimization places the volume control in its best operating range. This exclusive Benchmark feature can provide substantial improvements in the performance of the playback signal chain.

Native DSD Conversion

The DAC3 supports native DSD conversion. This feature was not available on the DAC1. DSD signals can be delivered to the USB or Coaxial inputs in DoP 1.1 format. The DSD signal is then routed directly to a bank of 1-bit DSD D/A converters. Four balanced 1-bit converters are summed together for each balanced output.

Digital Pass-Through

The second coaxial input (D4) can be reconfigured as a digital output. When operating as an output, any selected digital input is passed through to D4 without any processing. Optical, coaxial, and USB inputs can be passed through to the D4 connector. This even includes special signals such as DoP, DTS, Dolby Digital, even when these signals cannot be decoded by the DAC3.

Polarity Control

Each digital input can be inverted, to correct polarity problems. Some listeners report that polarity is incorrect on some recordings, and that they enjoy an improved listening experience when this is corrected. To toggle, use the POLARITY button on the front panel or press and hold the ON button on the remote.

HT Mode

The HT mode sets the volume control to a calibrated level that is near its maximum setting. In HT mode the analog gain is set to 0 dB (unity gain). Likewise the digital attenuation is set to 0 dB (maximum output). The HT light is illuminated when the HT mode is active.

The HT mode is similar to the CALIBRATED switch setting on the DAC1 except that it is programmable per input. This flexibility allows seamless integration into home theater systems where the DAC3 handles the main left and right channels.

Bi-directional 12V Trigger

The 12 Volt trigger can be connected to other audio components so that an entire audio system can turn on and off in a sequenced fashion. The DAC3 trigger I/O can be connected to a preamplifier, power amplifier, or both. The DAC3 will pull the trigger I/O to 12 volts DC while the DAC3 is on. If the DAC3 is off and an external device pulls the trigger I/O to 12 volts, the DAC3 will turn on.

Auto-On Function

The DAC3 can be programmed to automatically turn on when AC power is applied. (Page 14)

Front Panel

DAC3 HGC

DAC3 L

Rear Panel

DAC3 HGC and DAC3 L

Quick Start Guide

Audio Inputs

The DAC3 features two stereo RCA analog inputs and five stereo digital inputs (2 coaxial, 2 optical, and 1 USB). The coaxial and optical inputs accept professional (AES) and consumer (S/PDIF) data formats at word lengths up to 24-bits.

Tip: We recommend using the coaxial or USB inputs for sample rates above 96 kHz. Optical interfaces are not always reliable at sample rates above 96 kHz.

Remote Control

The remote control is designed to have a long operating range. In most applications it is not necessary to point the remote directly at the DAC3.

The chart at the right summarizes the functions of the IR remote control.

OFF	Turns the unit off. Any devicesslaved to the 12V TRIGGER willalso turn off in a controlledsequence.Press and hold the OFF button for3 seconds to force the 12VTRIGGER off (only necessarywhen another device is acting as aTRIGGER BUS MASTER).
ON	Turns the unit on. Any devicesslaved to the 12V TRIGGER willalso turn on in a controlledsequence.Press and hold the ON button for3 seconds to toggle thePOLARITY function.
VOLUME	Turns the volume up or down.
DIM	Toggles the -20 dB DIM function.
MUTE	Toggles the MUTE function.Press and hold the MUTE buttonfor 3 seconds to toggle the HTmode on the selected input.
INPUT	Selects the inputs.
D1	Selects optical digital input D1.
D2	Selects optical digital input D2.
D3	Selects coaxial digital input D3.
D4	Selects coaxial digital input D4.
USB	Selects USB input.Press and hold the USB button for3 seconds to toggle between theUSB 1.1 and USB 2.0 modes.
Analog	Selects analog input A1 and thentoggles between A1 and A2.

Front Panel Controls

Close-up of a mechanical control panel with two circular buttons and a black dial (no visible text or symbols)

The front panel controls duplicate all of the functions that are available from the remote control.

One additional function, AUTO-ON, is only controllable from the front panel. The AUTO-ON function keeps the DAC3 on whenever AC line voltage is supplied.

Tip: When AUTO-ON is enabled, a switched AC outlet can be used to turn your system on and off. The 12V TRIGGER I/O can be used as a trigger output to control the power state of additional components.

The chart at the right summarizes the functions of the front-panel controls.

POWER	Turns the unit on or off. Any devices slaved to the 12V TRIGGER will also turn on or off in a controlled sequence.Press and hold the POWER button for 3 seconds to force the 12V TRIGGER off (only necessary when another device is acting as a TRIGGER BUS MASTER).Starting with the unit off, press and hold the POWER button for 3 seconds to set the AUTO-ON function.Starting with the unit on, press and hold the POWER button for 3 seconds to clear the AUTO-ON function.If AUTO-ON is set, the POWER button will toggle MUTE on and off (the unit will remain on).
DIM/ MUTE	Press once to toggle the -20 dB DIM function.Double tap to set the MUTE function.
INPUT	Selects the inputs.Press and hold both input buttons for 3 seconds to toggle between the USB 1.1 and USB 2.0 modes.
VOLUME (knob)	This motor-driven knob can be turned by hand at any time (even when being driven by the motor).If HT mode is off, the motor drive will release when the knob is held or turned by hand. If HT mode is on, the motor drive will attempt to return the volume control to the HT setting.

Front Panel Displays

There are sixteen status indicator lights on the front panel. At least one light will be illuminated whenever power is on.

Input Indicators

The input indicators show which input is selected.
A flashing light indicates an error on a digital input.
The HT light shows that HT mode is active.

A1	A solid blue light indicates that analog input A1 is selected.
A2	A solid blue light indicates that analog input A2 is selected.
U	A solid blue light indicates that the USB input is selected and operating normally. A blinking blue light indicates that the input is selected but a connection to a computer has not been established.
D1	A solid blue light indicates that optical input D1 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
D2	A solid blue light indicates that optical input D2 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
D3	A solid blue light indicates that coaxial input D3 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.
D4	A solid blue light indicates that coaxial input D4 is selected and operating normally. A blinking blue light indicates that the input is selected but audio data is not being received.

Note: D4 cannot be selected if the Digital Pass Through function is enabled. Instructions for configuring this jumper-selected function can be found in the Internal Settings section of this manual (Page 29).

Input Error Codes

The input indicators flash when errors are present on the selected digital input. There are no error indications for analog inputs. Use the following table to diagnose the problem:

Slow Flash (2Hz)	No digital signal (output muted)
Med. Flash (7Hz)	Data transmission errors or Non-PCM (output muted)
Rapid flashes (14Hz)	Non-audio data is being received (output muted)
Intermittent flashes	Some data corruption is occurring, converter may be interpolating to replace invalid samples, check the cable.

Tip: Common causes of input errors:

• Disconnected or faulty cable
• Use of excessively long digital cables
• Use of analog cables for digital signals
- Use of optical cables for sample rates exceeding 96 kHz
• Incompatible data type (AC3, ADAT, etc.)
• Non-audio data is being received

HT Indicator

HT

A solid light indicates that the HT mode is active on the selected input and the volume control is in the factory calibrated position (near full clockwise). A blinking light indicates that the HT mode is active but the volume control has not yet reached its calibrated position. The HT light and DIM/ MUTE light will blink together if the unit is muted while HT mode is active.

DIM, MUTE, and POLARITY Indicators

DIM/ MUTE	A solid red light indicates that the unit is in DIM mode. A slow flashing red light indicates that the unit is in MUTE mode. A rapidly flashing red light indicates that the remote control is sending commands.
POLARITY	Yellow light indicates that the POLARITY inversion function is active.

Digital Format Indicators

Two lights indicate the measured word length of the selected digital input.

Four lights indicate the sample rate and format of the selected digital input.

Tip: Computers, disk players, and streaming devices often subject the digital signal to sample rate conversion, changes in word length, PCM to DSD conversions, and other forms of digital processing that may degrade the quality of the audio. This display makes it easy to detect these processes.

Word Length Indicators

The 16 and 24 lights indicate the measured word length of the selected digital input. The DAC3 detects active data bits and displays the results as follows:

16 Only	Measured input word length is 16 bits.
16 and 24	Measured input word length is 17 to 23 bits.
24 Only	Measured input word length is 24 bits.
Both Off	Measured input word length is less than 16 bits.

Format indicators

The 44, 48, 2X, 4X, and DSD lights indicate the sample rate and format of the selected digital input as follows:

44 Only	The input format is PCM at a sample rate of 44.1 kHz (CD sample rate).
48 Only	The input format is PCM at a sample rate of 48 kHz (often used with video).
44 and 2X	The input format is PCM at a sample rate of 88.2 kHz (high-resolution audio format).
48 and 2X	The input format is PCM at a sample rate of 96 kHz (high-resolution audio format).
44 and 4X	The input format is PCM at a sample rate of 176.4 kHz (high-resolution audio format).
48 and 4X	The input format is PCM at a sample rate of 192 kHz (high-resolution audio format).
DSD(4x and 2X)	The input format is 1-bit DSD at a sample rate of 2.8224 MHz (high-resolution audio format). Note: DSD must be streamed in DoP format.
All Off	Digital signal is not present or is not in a supported format.

Headphone Jacks

(DAC3 HGC only)

The left-hand jack mutes the XLR and RCA outputs.

The right-hand jack keeps all outputs active.

Headphone Mute Switch

The left-hand headphone jack includes a switch that mutes the main analog outputs (XLR and RCA) when a headphone plug is inserted. This feature allows the listener to switch from loudspeaker to headphone playback seamlessly. This Auto-Mute feature can be disabled with internal jumpers.

Note: Instructions for setting the Auto-Mute jumpers can be found in the Internal Settings section of this manual (Page 27).

Tip: Use the left-hand jack to mute your loudspeaker system. Use the right-hand jack to keep all outputs active.

Driving Two Sets of Headphones

The HPA2 ^TM is specifically designed with enough power to drive two sets of headphones.

Tip: The Volume Control simultaneously adjusts the level for both jacks. If two listeners will be simultaneously using the headphone outputs, we recommend using headphones with identical or similar voltage sensitivities.

HPA2™ Headphone Power Amplifier

The headphone jacks are driven by Benchmark's HPA2™ headphone power amplifier. This small and very clean power amplifier can deliver the current and voltage required by some of the most demanding headphones. The output impedance of the HPA2™ is very close to 0 Ohms. This low output impedance delivers a high damping factor so that the amplifier can maintain precise control over the headphone transducers.

Headphone voltage sensitivities vary substantially, so we have equipped the HPA2™ with Gain-Range jumpers that can be used to customize the headphone amplifier to your favorite headphones. If you find that you have too much output (volume control set below 11 o'clock), there are internal jumpers that can be adjusted to decrease the output level by 10 dB or 20 dB relative to the factory default setting.

Note: Instructions for setting the headphone Gain-Range jumpers can be found in the Internal Settings section of this manual.

Tip: For optimal performance, the headphone Gain-Range jumpers should be set so that comfortable listening levels occur when the volume control is set above the 11 o'clock position.

Operational Details

DIM and MUTE Functions

Definition: If the DIM, MUTE, and HT modes are all off, the DAC3 is in NORMAL mode.

Definition: The NORMAL volume setting is the last volume setting that was in use before the DIM, MUTE, or HT modes were activated.

DIM Function

The DIM function reduces the output level by 20 dB. To toggle between NORMAL and DIM volume, press the DIM button on the remote or the DIM/ MUTE button on the front panel.

The red DIM/ MUTE light will turn on whenever DIM is active.

When DIM is activated, the NORMAL volume setting is stored in memory while the volume control ramps down by 20 dB. When DIM is deactivated, the volume control ramps back to the NORMAL volume setting that was stored in memory.

The DIM function makes it convenient to fade back and forth between normal and background playback volume levels.

TIP: In the studio, the DIM function allows a temporary reduction in level without losing the volume setting that was being used for monitoring.

Tip: In home applications the DIM function allows temporary reductions in volume during TV commercial breaks, phone calls, or other interruptions, without losing the volume setting that was being used for normal listening.

If the volume is adjusted while DIM is active, it will not change the NORMAL setting unless the DIM volume is turned up above the last NORMAL setting. If the volume control is turned up by more than 20 dB after DIM is activated, the DIM mode will automatically deactivate, the DIM light will turn off, and the saved NORMAL setting will be replaced by the current volume setting.

DIM cannot be activated when HT mode is enabled.

With digital inputs, DIM will reduce the output level by exactly 20 dB. With analog inputs, DIM will reduce the output level 20 dB +/- 0.5 dB.

MUTE Function

The MUTE function immediately mutes all outputs. To toggle this function, press the MUTE button on the remote or double-tap the DIM/ MUTE button on the front panel.

The red DIM/ MUTE light will flash at a 1 Hz rate whenever MUTE is active.

When MUTE is activated from a NORMAL listening mode, the audio will immediately mute while the motor-driven volume control ramps down to the -20 dB DIM position. When MUTE is released, the output will unmute at the DIM volume position and then ramp back up to the previous setting. This movement of the motor-driven volume control provides a soft unmute when MUTE is released. It also allows immediate transitions between MUTE and DIM.

Tip: If the unit is in MUTE, press the DIM key to immediately enter the DIM mode.

Tip: If the unit is in MUTE, press the ON key to enter the NORMAL mode.

Tip: if the unit is in DIM, press the MUTE key to toggle between DIM and MUTE.

Auto-On Function

The DAC3 can be programmed to automatically turn on whenever AC power is applied. This function allows automation using switched AC outlets. When AUTO-ON is

enabled, the DAC3 cannot be turned off without removing AC power.

The AUTO-ON function is programmed by pressing and holding the POWER button on the front panel for three seconds. It is the only function that cannot be programmed from the remote control. This limitation prevents accidental access to this special feature.

Enabling AUTO-ON

Starting with the DAC3 off, press and hold the POWER button for 3 seconds.

If AUTO-ON has been successfully enabled, the POWER button will now function as a MUTE button. The OFF button on the remote will also function as a MUTE button when AUTO-ON is enabled.

Disabling AUTO-ON

Starting with the DAC3 on, press and hold the POWER button for 3 seconds. At the end of 3 seconds the DAC3 will power down if the AUTO-ON mode has been successfully disabled.

Bi-directional 12V Trigger

Benchmark has reinvented the 12 volt trigger by adding bi-directional signaling. The trigger connection on the DAC3 can be used as an input, an output, or both. It is compatible with any common 12 volt trigger input or output. The 12V TRIGGER I/O can be used to turn other audio components on when the DAC3 turns on. The DAC3 can also turn on and off in response to other connected components. The Benchmark bi-directional 12V Trigger is compatible with virtually all trigger systems.

The 12V TRIGGER I/O can be connected to the trigger input or output ports on a preamplifier, power amplifier, or both.

The DAC3 can send a 12 Volt DC trigger signal to start other components in the system, or it can wake up in response to an externally generated trigger signal. The DAC3 automatically configures its trigger I/O port as an input (slave) or output (master).

Trigger Output (DAC3 is Master)

When the DAC3 is turned on using the POWER button (on the front panel), or the ON button (on the remote), the DAC3 configures itself as a trigger master and will drive the 12V TRIGGER I/O to 12 volts DC and hold it there while the DAC3 is on. The trigger output signal generated by the DAC3 is delayed so that the DAC3 can stabilize before downstream devices (such as power amplifiers) turn on. When powering down, the DAC3 will mute before allowing the trigger line to drop low. The DAC3 keeps the internal power supplies running for 10 seconds after dropping the trigger. This delay gives other triggered components ample time to mute and shut down.

If the AUTO-ON function is enabled, the DAC3 will automatically turn on when AC power is applied, configure itself as a trigger master, and ignore any external signaling on the 12V TRIGGER I/O line. In AUTO-ON mode, the DAC3 will always drive the 12V TRIGGER I/O line to 12 V (after a short start-up delay).

Trigger Input - (DAC3 is Slave)

If the DAC3 is off and an external device pulls the trigger I/O to 12 volts, the DAC3 will configure itself as a trigger slave and will follow the actions of the trigger input. The DAC3 will then turn off when the external device stops sending the 12 V trigger.

Typical Trigger Applications

In most systems, the 12V TRIGGER will be used to connect the DAC3 to one other device. The DAC3 can be connected to the first trigger input at the beginning of a trigger chain, or it can be connected to the last trigger output at the end of the chain (less common).

Typical trigger applications:

• DAC3 → Amplifier
• DAC3 → Amplifier → Amplifier
• DAC3 → Preamplifier → Amplifier
- AVR → DAC3, and AVR → Amplifier (AVR with 2 trigger outputs controls DAC3 and power amplifier)

Trigger Bus Applications

The Benchmark bi-directional trigger system also supports multiple trigger ports wired together on a bus.

A group of Benchmark trigger ports can be connected to a group of non-Benchmark trigger input ports to form a single trigger bus. A bus should never be connected to more than one non-Benchmark trigger output port. If an output port is connected to the bus, this device should be used to start the audio system.

A 3.5 mm (1/8") TRS "Y" cable can be used to split the trigger output of the DAC3 to feed more than one trigger input.

Benchmark AHB2 power amplifiers have two trigger I/O ports that are wired in parallel. This makes it easy to connect more than one power amplifier to a trigger bus (without the use of a "Y" cord). Connect a trigger cable between the DAC3 and the first amplifier. Use another trigger cable to connect this amplifier to the next amplifier. Any number of Benchmark amplifiers can be added to the trigger bus. The DAC3 will turn on first, and after a delay, all of the amplifiers will turn on together.

Bi-Directional Trigger Applications

Benchmark products support bi-directional communications over a trigger bus. Any Benchmark product connected to the bus can turn the entire system on or off. Because of the bi-directional design, any power button on a Benchmark DAC3 or AHB2 can be used to start or stop the system.

The Benchmark device that starts the system will become the trigger master. If the trigger master is turned off, all slave devices will follow. If a slave device is turned off, all other devices will stay on.

If the DAC3 is used to turn the system on, any connected AHB2 amplifiers will become slave devices and they can be turned off without shutting down the DAC3. This feature makes it easy to turn the AHB2 amplifier(s) off when listening to headphones.

Slave devices can force the entire trigger bus to shut down if the POWER button or OFF button is pressed and held for 3 seconds.

Tip: Press and hold the POWER button on any Benchmark device for 3 seconds to force a shutdown of the entire trigger-connected system.

Trigger Specifications

The Benchmark 12V TRIGGER I/O has a wide operating range to allow interfacing with most other DC trigger systems. It should only be used with trigger inputs that are designed to tolerate 12 VDC.

• 12 VDC 200 mA current-limited output
- Input responds to 3.3 V logic and higher
• Maximum input voltage = 30 VDC
• Maximum reverse input voltage = -0.3 VDC
- Input Impedance = 20 k Ohms
• 1/8" (3.5 mm) TRS jack
• Tip = 12 Volt Trigger I/O
- Ring = no connection
- Sleeve = chassis ground

HT Mode

The HT mode sets the volume control to a calibrated level that is near its maximum setting.

The HT mode has three distinct applications:

• Volume Control Bypass - useful when the system has an upstream digital volume control or a downstream analog volume control
- Home Theater Bypass - allows high-quality stereo playback on a system that is also used for surround applications
- Calibrated Output - useful in studio applications where calibrated levels are needed

In HT mode the analog gain is set to 0 dB (unity gain, RCA to RCA). Digital inputs are calibrated to +24 dBu at 0 dBFS (+4 dBu at -20 dBFS) measured at the XLR outputs, and 2 Vrms measured at the RCA outputs. The HT light is illuminated when the HT mode is active.

Each input channel can be programmed individually by pressing and holding the mute button for three seconds. The HT mode is similar to the CALIBRATED switch setting on the DAC1 except that the HT mode can be programmable separately for each input. This flexibility allows seamless integration into home theater systems where the DAC3 handles the main left and right channels.

HT Mode - Volume Control Bypass

The HT mode is useful whenever the system volume will be controlled before or after the DAC3. It is usually best to avoid having two cascaded volume controls in a playback system. Dual controls will usually degrade the noise performance of the system and they can lead to confusion.

If the DAC3 feeds a preamplifier, the preamplifier will provide a downstream analog volume control for the system and the DAC3 should be placed in HT mode for all inputs.

If the DAC3 is directly feeding an amplifier, but one or more sources have volume controls, the sources with volume controls can be set to HT mode.

Example 1: The USB input is fed from a computer that has an internal digital volume control. If you wish to use the volume control in the computer exclusively, you will want to program the USB input with the HT mode on. All other inputs will have the HT mode turned off. If you do not wish to use the computer volume control, leave the HT mode off and disable the computer volume control (or set it to maximum).

Example 2: One of the analog inputs on the DAC3 is fed from a preamplifier and the preamplifier is being used to control the system playback. Set this analog input to HT mode on.

HT Mode - Home Theater Bypass

The home theater bypass is useful when you have a home theater system that will also be used for playing stereo recordings. The DAC3 will directly drive the left and right power amplifiers while the AVR drives all other speakers. The analog left and right line-level outputs of the AVR will be connected to one set of analog inputs on the DAC3 (usually A1). Stereo sources will be connected directly to the digital inputs on the DAC3. Surround sources will be connected directly to the inputs on the AVR.

When playing stereo recordings, digital feeds are sent directly to the DAC3 and the volume control on the DAC3 is used to control the playback level (HT mode must be off on all digital inputs). This configuration gives the best-possible performance for stereo applications because it eliminates the AVR from the stereo playback chain. If the stereo system includes a turntable and an outboard phono preamplifier, the outputs of the phono preamplifier can be connected directly to the

second set of analog inputs on the DAC3 (HT mode off, analog input A2).

When playing movies and other surround sources, analog signals from the AVR would pass through the DAC3 at unity gain (HT mode on, analog input A1).

For stereo applications, digital sources would feed the DAC3 and the volume control on the DAC3 would control the playback level (HT mode off, digital inputs).

HT Mode - Calibrated Output

Any digital input can be set to the factory-calibrated fixed-gain by turning the HT mode on. In HT mode, the analog audio outputs are set to factory calibrated levels. This mode is useful in studio applications where calibrated interface levels are used between various pieces of equipment. (Note: This function is similar to the calibrated mode on the DAC1.)

USB MODE Selection

The DAC3 supports two USB MODES:

• USB Audio 1.1 mode - up to 24 bits at 96 kHz
- USB Audio 2.0 mode - up to 24 bits at 192 kHz plus DSD in DoP 1.1 format

Caution: Close all USB audio playback applications before changing the USB MODE. If an audio application is playing while the USB MODE is changed, the audio application may freeze.

Note: The computer and DAC3 must be connected and both must be on before the USB MODE can be changed.

To change the USB MODE, select the USB (U) input on DAC3 and then press and hold the USB button on the remote control for 3 seconds. If a remote control is not available, simultaneously press and hold both INPUT buttons on the front panel for 3 seconds.

After holding the button(s) for 3 seconds, either the 4X lamp or the 2X lamp will flash once indicating the new USB MODE. A flash of the 4X lamp indicates that the unit is now in USB Audio 2.0 mode. A flash of the 2X lamp indicates that the unit is now in USB Audio 1.1 mode.

Tip: The 4X or 2X lamp will flash once every time the USB input is selected. This flash provides a convenient indication of the current USB MODE.

Tip: Avoid any unnecessary switching between USB MODES. Rapid switching between modes can confuse some operating systems.

Driving Power Amplifiers

The DAC3 is designed to directly drive virtually any audio power amplifier or powered monitor. This direct connection provides the cleanest and shortest path from the digital source to the monitor output.

Tip: Benchmark does not recommend placing audio devices between the DAC3 and the power amplifier unless these devices are providing an indispensable system function. A direct connection between the DAC3 and the power amplifier will always provide the best system-level performance (SNR and THD+N).

The RCA and XLR outputs on the DAC3 are equipped with low-impedance high-current drivers. These robust outputs are well equipped to drive a wide variety of input impedances. The DAC3 outputs remain clean when driving amplifiers that present difficult loads (high input capacitance and/or low input impedance).

The XLR outputs on the DAC3 are equipped with jumper-configured passive low-impedance output pads. These pads can be set to an attenuation of 0 dB (pad off), 10 dB, or 20 dB. The pads should be used to match the output level of the DAC3 to the input sensitivity of the power amplifier. Most power amplifiers and powered monitors will require the use of the 10 dB or 20 dB pads.

Use the 0 dB setting when driving a Benchmark AHB2 power amplifier.

Tip: The Benchmark AHB2 power amplifier has a unique low-gain topology that allows it to accept full studio-level input signals. This high-level interconnection provides a very low-noise connection between the DAC3 and the AHB2. Set the input SENSITIVITY switch on the AHB2 to 22 dBu (all the way down). This places the AHB2 full-power output point at an input level of 22 dBu. This level is exactly 2 dB lower than the calibrated HT output level of the DAC3 (when the pads are set to 0 dB). This configuration optimizes the gain-staging between the DAC3 and the AHB2 while placing the DAC3 volume control in the proper range.

Tip: If you are using a DAC3 with non-Benchmark power amplifiers, the XLR pads should be set so that comfortable listening levels occur when the VOLUME control is set above 11 o'clock. This will optimize the gain-staging between the DAC3 and your power amplifier.

Tip: Increase the pad setting if a comfortable listening level is reached at a VOLUME control setting below the 11 o'clock position.

Tip: Decrease the pad setting if a comfortable listening level cannot be reached when the VOLUME control is fully clockwise.

Instructions for setting the XLR pad jumpers are detailed in the Internal Settings section of this manual. The DAC3 is shipped with the XLR pads disabled (set to 0 dB). No adjustments will be necessary if you will be using a Benchmark AHB2 power amplifier.

HPA2 ^TM Headphone Amplifier

(DAC3 HGC model only)

The left headphone jack has a mute switch that mutes all of the analog outputs on the back of the DAC3. The right headphone jack does not have a mute switch. The audio output on both jacks is wired in parallel and is driven by Benchmark's HPA2 ^TM headphone power amplifier.

The HPA2 ^TM is one of the most transparent headphone amplifiers available. It also is able to deliver high current and/or high signal levels making it well suited for a wide variety of headphones. The near 0-Ohm output impedance provides outstanding damping of headphone drivers. This damping reduces distortion while maintaining precise control of the frequency response at the output of the amplifier.

The HPA2 ^TM has a set of 3-position gain-range jumpers that can be used to increase or decrease the gain by 10 dB relative to the factory calibrated setting.

The jumpers change the gain of the HPA2 ^TM headphone amplifier without changing the output impedance. This keeps the output impedance of the HPA2 ^TM constant and very near 0 Ohms. External attenuators should never be inserted after a headphone amplifier as this would change the output impedance and alter the frequency response of the headphones.

Proper gain settings are important for maximizing the SNR of the headphone monitoring system. With proper settings, the full performance of the DAC3 can be delivered to the headphones for critical monitoring tasks and for maximum musical enjoyment.

Tip: When the headphone gain jumpers are set properly, a normal listening level will be achieved at a VOLUME control setting above the 11 o'clock position.

Tip: If a normal listening level is achieved below an 11 o'clock VOLUME setting, the headphone gain is too high, and the gain should be decreased.

Tip: If the level is too low at the maximum VOLUME setting, the headphone gain is too low, and the gain should be increased.

Digital Pass-Through

The second coaxial input (D4) can be reconfigured as a digital output. When operating as an output, any selected digital input is passed through to D4 without any processing.

Optical, coaxial, and USB inputs (U, D1, D2 and D3) can be passed through to the D4 connector. The signals are buffered but are not processed in any way. For this reason, any data format can be passed through to the D4 connector, even when these formats cannot be decoded by the DAC3. Surround formats, such as DTS, Dolby Digital, cannot be decoded by the DAC3, but they can be passed to a surround system using the digital pass-through function.

The digital pass-through can also be used to provide the following digital signal conversions:

• Optical to Coaxial
• USB to Coaxial
  • Coaxial to Coaxial (buffering)

DoP encapsulated DSD can also be passed through D4. DSD files on a computer can be sent in DoP to the USB input on the DAC3. The USB input can be routed to coaxial output D4. This output can be recorded by any 24-bit, 176.4 kHz digital recorder with a coaxial input. The PCM digital recorder can then be used to play the DSD recordings.

Firmware Version Identification

The firmware version is displayed during the lamp test while the DAC3 is turning on. At least one lamp in the INPUT INDICATOR will flash rapidly while the remaining lamps will be on. The flashing lamps identify the firmware version. The values of each lamp

Digit 1			Digit 2
8	D1		D2	.8
4	U		D3	.4
2	A2		D4	.2
1	A1		HT	.1

are shown in this chart. Add the values of all flashing lamps to determine the version number. If no lamp flashes in the

second column, the second digit is a 0.

Example 1: The A1 lamp is the only lamp that flashes. The firmware version is 1.0.

Example 2: The A1 and HT lamps flash. The firmware version is 1.1.

Rear Panel

DAC3 HGC and DAC3 L

Inputs

There are seven stereo inputs on the DAC3:

• A1 - RCA L & R Analog Inputs
• A2 - RCA L & R Analog Inputs
• USB - USB Audio 1.1 or 2.0 Input
• D1 - Optical Digital Input
• D2 - Optical Digital Input
• D3 - Coaxial Digital Input
• D4 - Coaxial Digital Input or Output*

These inputs are selected using the INPUT buttons on the front-panel or on the remote-control.

* D4 can be jumper-configured as a digital PASS-THROUGH output. When enabled, the selected digital input will be routed to the internal D/A converter and to output D4. The selected input will be buffered and sent to output D4 even if the format cannot be decoded by the DAC3.

The digital inputs support PCM stereo AES/EBU and SPDIF digital formats. Maximum

word length is 24-bits. Maximum sample rate is 192kHz.

The digital inputs also support DSD stereo at a sample rate of 2.8224 MHz using DoP 1.1 encapsulation.

The USB input has two operating modes:

• USB Audio 1.1 - PCM up to 24-bits at 96 kHz
• USB Audio 2.0 - PCM up to 24-bits at 192 kHz and DSD (DoP 1.1 format)

Caution: The optical inputs (D1 and D2) are not recommended for DSD or for sample rates above 96 kHz. Optical connections may be unreliable at sample rates above 96 kHz.

Tip: The DAC3 will not decode multichannel digital formats such as AC3, and Dolby Digital. The audio will mute and the INPUT INDICATORS will flash whenever an incompatible format is connected to the selected digital input. If the PASS-THROUGH mode is enabled, these multichannel formats can be sent to a surround processor using connector D4 as a digital output.

Caution: The 12V TRIGGER I/O is not an audio connection! This is a 12V DC connection for synchronizing the on and off sequencing of an entire audio system.

Analog Inputs – RCA Unbalanced

The DAC3 has two sets of unbalanced stereo analog inputs with female RCA connectors.

The analog inputs can be used for devices such as:

• Phono preamplifiers
• FM Tuners
• Tape Transports
• Analog VCR outputs
• iPod and MP3 devices
  • Outputs from analog mixing consoles

Digital Inputs - Overview

All of the digital inputs on the DAC3 use Benchmark's UltraLock3™ system to remove virtually all of the interface jitter. The result is that all digital inputs deliver identical audio performance. The USB, optical, and coaxial digital inputs will all sound identical if they receive identical data.

Computer Input - USB

The USB input accepts a Type-B male USB connector. A Type-A to Type-B USB cable is provided with the DAC3. The USB cable connects the DAC3 directly to a computer's USB output.

The USB input supports 44.1, 48, 88.2, 96, 176.4, and 192 kHz PCM sample rates at word lengths up to 24-bits. The USB input also accepts DSD in DoP 1.1 format.

The DAC3 can be configured as a USB Audio 1.1 or USB Audio 2.0 device. Press and hold the USB button on the REMOTE for three seconds to toggle the USB MODE. If a remote is not available, simultaneously press and hold both input buttons on the front panel for three seconds.

The USB AUDIO 1.1 mode does not require the installation of a driver. It allows a quick driverless connection to windows machines when playing sample rates of 96 kHz or less. In this mode, Windows machines can begin streaming audio within seconds after the DAC3 is connected for the first time. No software or hardware configuration is usually required.

USB Audio 2.0 is required for DSD and for all PCM sample rates exceeding 96 kHz. Windows computers require a driver to support the USB Audio 2.0 mode.

The USB Audio 1.1 mode was tested for compatibility with Windows XP, Vista, 7, 8 and 10, Mac OS X, and iPads using the 30-pin to USB Camera Kit. No driver installation is required for any of these systems when operating in USB Audio 1.1 mode.

The USB Audio 2.0 mode was tested for compatibility with Windows XP, Vista, 7, 8 and 10 (driver installation is required for all Windows versions). It was also tested for compatibility with Mac OS X starting with version 10.6 (operation is driverless for all OS X versions).

Optical Digital Inputs - D1 and D2

The optical input connectors (D1 and D2) are commonly known as TOSLINK connectors. The TOSLINK optical connectors used on the DAC3 are designed to work well at sample rates up to 96 kHz. Maximum word length is 24-bits. All sample rates between 28 and 96 kHz are supported. The optical inputs may be unreliable at sample rates above 96 kHz. The optical inputs will accept professional AES/EBU data formats or consumer S/PDIF data formats.

Tip: The optical inputs include dust caps. Keep these in place if the input is not being used.

Coaxial Digital Inputs - D3 and D4

The coaxial digital inputs (D3 and D4) use female RCA connectors. The input impedance is 75 Ohms. Maximum word length is 24-bits. All sample rates between 28 and 195 kHz are supported. The coaxial digital inputs will accept professional AES/EBU data formats or

consumer S/PDIF data formats. The coaxial inputs also accept DSD in DoP 1.1 format.

The coaxial digital inputs are DC isolated, current limited, and diode protected. The RCA body is bonded directly to the chassis to prevent currents in the internal ground system. This direct bonding also maximizes RF shielding.

Caution: Use 75-Ohm coaxial cables for digital audio connections D3 and D4. Digital interfaces require the use of matched impedances. Do not use 50-Ohm coaxial cables, twisted pair cables, or any non-coaxial cables for digital audio. The digital inputs may not function, or may be unreliable if the incorrect cable is used.

Tip: The RCA analog inputs and outputs have no restrictions on cable type. To avoid confusion, we recommend using 75-Ohm coaxial cables for all RCA connections. 75-Ohm coaxial cables are compatible with digital audio, analog audio, and video.

Note: The Coaxial inputs (D3 and D4) accept professional or consumer digital audio formats. The AES3-id and SMPTE 276M standards specify a 75-Ohm, 1 Vpp, professional format which is also known as AES/EBU and is commonly used in video production facilities. The IEC 609588-3 standard specifies a 75-Ohm, 0.5 Vpp, consumer format which is also known as S/PDIF, and is commonly used in hi-fi equipment. The coaxial inputs are designed to accept either type of signal.

12V TRIGGER I/O

The Benchmark bi-directional 12V TRIGGER is compatible with virtually all trigger systems. The 12V TRIGGER I/O connection on the DAC3 can be used as an input, an output, or both. It is compatible with most 12 volt trigger inputs and outputs. The 12V TRIGGER can be used to turn other audio components on when the DAC3 turns on. The DAC3 can also turn on and off in response to trigger signals sent from other components.

The 12V TRIGGER I/O can be connected to the trigger input or output ports on a preamplifier, power amplifier, or both.

The DAC3 can send a 12 Volt trigger signal to start other components in the system, or it can wake up in response to an externally generated trigger signal. The DAC3 automatically configures the 12V TRIGGER I/O port as an input (slave) or output (master). See the Bi-directional 12V Trigger section for more information.

The Benchmark 12V TRIGGER I/O has a wide operating range to allow interfacing with most other DC trigger systems. It should only be used with trigger inputs that are designed to tolerate 12 VDC.

• 12 VDC 200 mA current-limited output
- Input responds to 3.3 V logic and higher
• Maximum input voltage = 30 VDC
• Maximum reverse input voltage = -0.3 VDC
- Input Impedance = 20 k Ohms
• 1/8" (3.5 mm) TRS jack
• Tip = 12 Volt Trigger I/O
- Ring = no connection
- Sleeve = chassis ground

Caution: The 12V TRIGGER I/O is not an audio connection! This is a 12V DC connection for synchronizing the on and off sequencing of an entire audio system.

Outputs

Analog Outputs

Close-up of an analog output panel with four gold-colored connectors and labeled ports (no readable text beyond labels)

The DAC3 has one pair of balanced XLR outputs and two pairs of unbalanced RCA outputs.

The DAC3 features high-current output drivers that are capable of driving 300-Ohm loads without an increase in distortion. They are also well suited for driving long cables or high-capacitance loads.

Balanced XLR Analog Line Outputs

Close-up of an analog output device showing two gold pins with labeled ports (R and L), no readable text or symbols beyond labels.

The Left and Right balanced outputs use Neutrik™ gold-pin male XLR jacks. The XLR shell and pin 1 (ground) are both directly bonded to the chassis to prevent currents in the internal ground system. This direct bonding also maximizes RF shielding.

The XLR outputs have passive attenuators that allow direct connections to a wide variety of audio devices without a loss of dynamic range. The 10 or 20 dB pads are usually required for direct interfacing to power amplifiers and powered speakers. The DAC3 ships with the pads disabled (0 dB setting). Use the 0 dB setting with the Benchmark AHB2 power amplifier. A full description of the output attenuators and instructions for

configuration is located in the Internal Settings section of this manual.

Industry-Standard XLR Wiring

• XLR pin 2 = + Audio Out
• XLR pin 3 = - Audio Out
• XLR pin 1 = Cable Shield

Caution: If the balanced XLR outputs are wired to an unbalanced input (using a special adapter cable), pin 3 must be left floating. Shorting pin 3 to ground will increase the temperature of the output drivers, will increase power consumption, and may cause distortion.

Unbalanced RCA Analog Outputs

Close-up of analog output ports with labeled pins (P, L) and four circular components, no readable text or symbols beyond labels

The Left and Right unbalanced outputs use female RCA jacks. The ground connections are bonded to chassis ground at the location where analog ground is bonded to the chassis. This minimizes the effects of ground loops caused by AC currents in the cable shield. The RCA output impedance is very low (30 Ohms). This makes these outputs well suited for driving high-capacitance loads and/or high-capacitance cables.

Caution: Mono summing with an RCA 'Y' cable is not recommended as this will cause high amounts of distortion. Mono summing with a 'Y' cable can be accomplished with the use of a modified cable by implementing a 1k Ohm series resistor in each leg of the 'Y'.

Note: The XLR pads do not have any effect on the level of the RCA outputs.

AC Power-Entry and Fuse Module

Input Voltage Range

Note: The DAC3 is equipped with a universal power supply. There is no voltage selection switch. AC voltage range is 88-264 VAC, 50-60 Hz.

Power Cord

Note: The AC power input uses a standard IEC type connector. One USA-compatible power cord is included with DAC3 converters. IEC style power cords in country-specific configurations are available in your locality.

Caution: Always use a grounded power cord. The DAC3 is equipped with a standard IEC power entry module. Use an IEC power cord that is equipped with the appropriate connector for your location. Cords are available from your dealer.

Fuses

Caution: For continued fire hazard protection always replace the fuses with the correct size and type (0.5A 250 V Slo-Blo® 5 x 20 mm - Littelfuse® HXP218.500 or equivalent). The fuse drawer includes two fuses. Always replace both fuses at the same time.

Internal Settings

Jumper-Configured Options

The following functions are jumper configured:

• XLR Output Pads
  • Headphone Mute Switches
• Headphone Gain
  • Digital Pass-Through

Removing Top Cover

The DAC3 cover must be removed to gain access to the jumpers. Do not attempt to remove the faceplate or rear panel.

Caution: The DAC3 contains static sensitive components. Static discharge may cause component failures, may affect the long-term reliability, or may degrade the audio performance. Use a static control wrist strap when changing jumper settings.

• Disconnect AC power by unplugging the power cord at the back of the DAC3.
• Remove the 8 screws holding the cover (4 on each side).
• Do not remove any screws on the front, rear, or bottom panels!
• Never remove the power entry safety cover in the rear corner of the DAC3.
• Always connect a static-control wrist strap to the chassis before touching any internal component.

XLR Output Pads

The XLR outputs are equipped with low-impedance passive pads that may be used to reduce the output levels while preserving the full dynamic range of the DAC3. The DAC3 ships with the pads disabled (0 dB setting).

Tip: To set the XLR outputs are factory-preset to deliver professional studio levels. Most home installations will require the use of the 10 dB or 20 dB pads.

Tip: Use the factory-default 0 dB setting with Benchmark's AHB2 power amplifier. When directly driving most other power amplifiers (or powered speakers), start with the 10 dB pad setting. If necessary, change the pads so that normal listening levels are achieved when the VOLUME control is between the 11 o'clock and 3 o'clock positions.

When the output pads are enabled, the output impedance changes slightly, and the maximum recommended XLR cable length is reduced as shown in Table 1. The table assumes a cable capacitance of 32 pF/foot and a maximum allowable loss of 0.1 dB at 20 kHz.

Table 1 - Cable Drive Capability

Balanced Output Drive Capability:
Attenuator	Output	Maximum Loss in dB
Setting (dB)	Impedance	Cable (ft) at 20 kHz
0	60 680	0.1
10 425 96		0.1
20 135 302		0.1

Unbalanced Output Drive Capability:

Output Maximum	Loss in dB
Impedance Cable (ft) at 20 kHz
30 1360 0.1

XLR Output Pad Jumpers

Four jumpers on four 6-pin headers (P8, P9, P10, and P11) allow selection of the output level at the XLR jacks. The jumpers are properly configured if a normal playback level is achieved when the VOLUME control is set above the 11 o'clock position.

One pair of 6-pin headers control the attenuation at each XLR jack as follows:

• 0 dB - (Attenuator disabled) - (Jumper plug between pins 1 and 2 of each header) - Factory Default
• -10 dB – (Jumper plug between pins 3 and 4 of each header)
• -20 dB – (Jumper plug between pins 5 and 6 of each header)

Figure 1 - Attenuators set to -10 dB

Headphone Switch Configuration

(DAC3 HGC only)

The left-hand headphone jack is equipped with a switch that will mute the analog outputs when a headphone plug is inserted. The right-hand headphone jack does not have a mute switch. In most cases it is convenient to have one jack that mutes the outputs and one that does not mute the outputs. If your

requirements are different the HEADPHONE SWITCH can be defeated.

Headphone Switch Disable

The HEADPHONE SWITCH on the left-hand headphone jack can be defeated by adding jumpers at JP1 and JP2.

• HEADPHONE SWITCH enabled (no jumpers at JP1 or JP2) - Factory Default
• HEADPHONE SWITCH disabled (jumpers installed at JP1 and JP2)

Figure 2 - Headphone Switch Enabled (Factory Default)

Figure 3 - Headphone Switch Disabled

Headphone Amplifier Gain

(DAC3 HGC only)

The gain range of the HPA2™ can be set using jumpers JP3 and JP4:

• Gain = 0 dB - see Figure 4
• Gain = -10 dB - see Figure 5 (Factory Default)
• Gain = - 20 dB - see Figure 6

The jumpers change the gain of the HPA2 ^™ headphone amplifier without changing the output impedance. This keeps the output impedance of the HPA2 ^™ constant and very near 0 Ohms. External attenuators should never be inserted after a headphone amplifier as this would change the output impedance and alter the frequency response of the headphones.

Proper gain settings are important for maximizing the SNR of the headphone monitoring system. With proper settings, the full performance of the DAC3 can be delivered to the headphones for critical monitoring tasks and for maximum musical enjoyment.

Tip: When the headphone gain jumpers are set properly, a normal listening level will be achieved at a VOLUME control setting above the 11 o'clock position.

Tip: If a normal listening level is achieved below an 11 o'clock VOLUME setting, the headphone gain is too high, and the gain should be decreased.

Tip: If the level is too low at the maximum VOLUME setting, the headphone gain is too low, and the gain should be increased.

Figure 4 - HPA2™ Gain is 0 dB

Figure 5 - HPA2™ Gain is - 10 dB

Close-up of a green printed circuit board with electronic components and a red arrow pointing to a component (no readable text or symbols)

Figure 6 - HPA2™ Gain is - 20 dB

Digital PASS-THROUGH Function

The digital PASS-THROUGH function can be enabled by moving both P14 jumpers toward the faceplate shown in Figure 7. Once the jumpers are moved into the position shown in Figure 7, D4 is configured as a digital audio output. When the PASS-THROUGH function is enabled, D4 cannot be selected as an input. Any other selected digital input will be routed to both the internal D/A converter and to output D4. The digital output at D4 is buffered, but is not processed. Many digital audio formats can be passed through to D4 (even when these formats cannot be decoded by the DAC3).

By default, D4 functions as a digital input and the jumpers are set according to Figure 8.

Close-up of a green printed circuit board with various electronic components and connectors, no visible text or symbols.

Figure 7 – Digital PASS-THROUGH Enabled

Close-up of a green printed circuit board with various electronic components and connectors (no readable text or symbols)

Figure 8 - Digital PASS-THROUGH Disabled (Factory Default)

Rack Mounting

An optional rack mount tray allows the mounting of any two 12 -wide Benchmark products in a single rack space. A blank plate can be added when only one unit is installed in the rack mount tray.

The Benchmark Rack Mount Tray and Benchmark 12 -Wide Blank Plate are available from Benchmark.

Benchmark Rack Mount Tray

Black metal shelf panel with mounting holes and a central mounting bracket (no text or symbols visible)

The Benchmark Rack Mount Tray mounts up to two 12 -wide Benchmark products in a single race space. The tray accepts any combination of 12 -wide Benchmark products (with or without rack-mount type faceplates).

Benchmark 12 -Wide Blank Plate

Black rectangular metal plate with four circular holes, no text or symbols visible

The Benchmark 12 -Wide Blank Plate is a 12 -wide 1-RU anodized aluminum panel for covering an unused slot in the Benchmark Rack Mount Tray. It is available in black or silver. The silver panel includes an engraved Benchmark logo.

Visit BenchmarkMedia.com for a complete selection of cable, accessories, and replacement parts.

DAC1, DAC2 and DAC3 Family History

The pristine audio performance of the award-winning DAC1 made it the 'Benchmark' of stand-alone D/A converters. The DAC1 USB, DAC1 PRE, and DAC1 HDR added many features to the basic DAC1 platform. Benchmark converters are in use in many of the world's top studios.

The following is a brief overview of the various Benchmark DAC1, DAC2 and DAC3 models:

DAC1 Series

DAC1

Benchmark's original DAC1 converter.

The DAC1 features included:

• Three digital inputs
  • XLR outputs with passive pads
• RCA outputs
• Analog volume control
• HPA2 ^TM headphone amplifier
• UltraLock ^TM jitter-attenuation system

DAC1 USB

The DAC1 USB introduced these improvements:

• AdvancedUSB™ computer input
- Mute switch on the left headphone jack
- Two headphone gain ranges
- High-current LM4562/LME49860 output stages - designed to drive difficult loads
• Lower output impedances

Benchmark's AdvancedUSB™ computer input was the first USB audio interface to support 96 kHz audio without the need to install special drivers.

DAC1 PRE

The DAC1 PRE added these improvements:

• Three coaxial digital inputs
• Three Headphone Gain Ranges
• LM4562/LME49860 opamps throughout
- Premium bulkhead-mounted RCA connectors

In order to provide room for the analog inputs, we removed the XLR digital input and replaced it with two additional coaxial digital inputs.

DAC1 HDR

The DAC1 HDR added:

• IR Remote Control
• HDR-VC™ (high dynamic range volume control).

The HDR-VC ^TM features a custom-made, motor-driven Alps potentiometer. The motor-driven control provides the audio performance of a manual control while adding the convenience of remote control.

DAC2 Series

DAC2 HGC

The DAC2 HGC maintains the familiar 12 -wide DAC1 form factor, but the entire product was redesigned from the ground up.

The DAC2 HGC features:

• Four 32-bit converters per channel
• Native 24-bit/192kHz PCM conversion
• Native 64X DSD conversion
• High-headroom digital processing
• UltraLock2 ^TM jitter attenuation
- Multi-mode asynchronous USB audio input
• Sample rate and word length displays
- Polarity control
• Home theater bypass
• Digital pass-through
• Bi-directional 12V trigger
- Two stereo analog inputs
• Three stereo analog outputs
- Two optical inputs
- High-efficiency low-noise power supplies

DAC2 L

The DAC2 L is identical to the DAC2 HGC except that the DAC2 L has no headphone amplifier.

DAC2 D

The DAC2 D is identical to the DAC2 HGC except that the DAC2 D has no analog inputs and no 12V trigger.

DAC2 DX

The DAC2 DX replaced the DAC2 D. The new model added an XLR digital input and the 12V trigger. It also added a second output bus so that one set of outputs could be placed in calibrated mode while the other was controlled by the volume knob.

DAC3 Series

On the surface, the DAC3 series converters look exactly like the DAC2 converters. They have the same controls, the same connectors, and even the similar-looking circuit boards. The difference is that many critical components and systems have been upgraded. The new DAC3 delivers lower THD, improved digital filtering, and faster PLL lock times.

The firmware, digital signal processing, and UltraLock™ clock system have all been upgraded in the new DAC3. Most notably, the DAC3 series includes the new ES9028PRO D/A converter. This groundbreaking D/A converter IC offers several significant improvements over the ES9018 converter used in the DAC2 series. Until the ESS PRO series was introduced, the ES9018 was the highest performance D/A converter IC available. The ESS PRO series converters are now setting this benchmark. The Benchmark DAC3 is one of the first products to feature this new 32-bit D/A converter.

Benchmark's ultra-clean analog stages, low-jitter UltraLock3 ^TM clock system, and high-headroom DSP leverage the full capabilities of the new ESS PRO series converters.

DAC3 vs. DAC2

The DAC3 series adds the following improvements over the DAC2 series:

• ESS SABRE-PRO D/A Conversion
• UltraLock3 ^TM clock system
- Instantaneous lock
- Instantaneous input switching
• THD reduction system
- 2nd-harmonic compensation
- 3rd-harmonic compensation
- Improved digital filters
- Lower passband ripple
- Flatter frequency response
• Higher maximum output level
- Increased Dynamic Range

Benchmark Technologies

Hybrid Gain Control™

HGC^TM is Benchmark's unique Hybrid Gain Control ^TM system. The DAC3 combines active analog gain control, passive low-impedance attenuators, a 32-bit digital gain control, and a servo-driven volume control.

All inputs are controlled by the rotary volume control. This volume control moves in response to commands from the remote control. Analog inputs are never converted to digital, and digital inputs never pass through an analog potentiometer. Digital inputs are precisely controlled in the 32-bit DSP system. The DSP system preserves precise L/R balance, and precise stereo imaging, while avoiding any source of noise and distortion.

Benchmark's unique passive output attenuators provide distortion-free gain reduction without reducing the dynamic range of the converter. The attenuators optimize the gain staging between the DAC3 and the power amplifier. This optimization is absolutely essential for maximizing the dynamic range of the entire playback system. Much of the success of the DAC1 and DAC2 converters can be attributed to the passive output attenuators. Musical details can be obscured by system noise whenever a preamplifier and power amplifier are improperly matched. The HGC™ system in your DAC3 will make full use of your power amplifier's dynamic range. Experience newly revealed details in your favorite recordings.

The front-panel volume control is a servo-driven gain control built around a custom-made Alps potentiometer. The custom Alps pot is equipped with a remote-controllable motor drive.

This potentiometer is equipped with a clutch which prevents damage from overriding the motor drive. If the pot is driven beyond the end of its range, it will not damage the motor. Also, if the pot is manually overridden, it will not damage the motor.

Native DSD Conversion

The digital coaxial inputs and the USB Audio 2.0 input on the DAC3 support native DSD conversion. DoP 1.1 DSD encapsulation is automatically detected on all digital inputs. The system seamlessly switches to native DSD conversion when DoP is detected. DoP 1.1 DSD encapsulation is supported by many media players. DSD downloads are now available from several sources.

Visit our website for an up-to-date list of DSD and PCM high resolution download sites.

High Headroom DSP

All of the digital processing in the DAC3 is designed with a headroom of 3.5 dB above 0 dBFS. A sinusoid that just reaches the maximum positive and negative digital codes has a level of 0 dBFS. If the peaks of the sinusoid occur between samples, higher signals can be captured without clipping. For a pure tone, the maximum intersample peak that can be represented by a PCM system is +3.01 dBFS.

Benchmark's high-headroom DSP can handle intersample peaks without overloading or clipping. Intersample peaks are cleanly rendered by the DAC3 and are delivered to the analog outputs without clipping or distortion. Very few D/A converters can make this claim!

In most D/A conversion systems, intersample peaks cause overloading of the upsampling interpolators and digital filters that are found in all sigma-delta converters. When overloads occur, bursts of non-harmonic distortion are produced. These bursts of high-frequency distortion may occur many times per second and may add a false brightness and harshness to the sound. This defect impacts PCM formats but does not impact 1-bit DSD formats. The absence of intersample clipping may explain some people's preference for DSD. The DAC3 delivers clean PCM conversion that meets or exceeds the clarity of DSD.

Intersample Overs
(1 = Maximum Digital Code)

Intersample overs are common in low sample rate (44.1 kHz and 48 kHz) commercial releases. Due to the mathematics and the bandwidth of typical input signals, intersample overs are less of a problem in high sample rate recordings. The reason for this is that the worst-case (+3.01 dB) intersample overs occurs for pure tones that are exactly 1/4 of the sample rate (as shown in the figure above). At the 44.1 kHz CD sample rate, the worst case occurs at 11.025 kHz. It turns out that many recordings have substantial peaks near this frequency. In contrast, at a sample rate of 88.2 kHz, the worst-case intersample overs occur at a frequency of 22.1 kHz where most musical sources have insufficient energy to produce significant intersample overs. The 88.2 kHz sample rate is still susceptible to intersample overs, but the magnitude of the worst-case overs tends to be much lower. For example, at 1/8th of the sample rate (11.025 kHz), the maximum intersample peak is about +0.66 dB instead of the 3.01 dB worst case at a sample rate of 44.1 kHz.

The biggest advantage of higher sample rates may be the immunity to intersample overs. If higher sample rates sound better, this difference may be entirely due to the absence of DSP overloads caused by intersample overs. Benchmark's high-headroom DSP renders low sample rates with the clarity and detail normally associated with high sample rates.

Conventional Interpolation
(Intersample Overs are Clipped)

PCM systems can accurately capture peaks that exceed 0 dBFS, but these peaks will overload the oversampling interpolators in most delta-sigma D/A converters. The solution is not to eliminate the interpolation process; the solution is to build interpolators with more headroom.

High-Headroom Interpolation (Intersample Overs are Not Clipped)

The interpolation process is absolutely necessary to achieve 24-bit state-of-the-art conversion performance. Unfortunately, intersample overs cause clipping in most interpolators. This clipping produces distortion products that are non-harmonic and non-musical. We believe these broadband distortion products often add a harshness or false high-frequency brightness to digital reproduction. The DAC3 avoids these problems by maintaining at least 3.5 dB of headroom in the entire conversion system. We believe this added headroom is a groundbreaking improvement.

32-bit SABRE-PRO D/ A System

Four balanced 32-bit D/A converters deliver audio to Benchmark's low-impedance current to voltage converters. The 4:1 redundancy reduces noise by 6 dB. The redundancy also reduces the THD. The conversion system at the core of the DAC3 is as good as it gets. The analog circuits that follow the D/A converter are carefully designed. Benchmark has leveraged its long history of building reference analog audio equipment to create an outstanding output stage.

Diagnostic Displays

Ever wonder why that 192 kHz 24-bit download on your computer just doesn't sound right? Your media player or computer may be downsampling to 44.1 kHz and/or truncating to 16-bits. Many media players and computer operating systems apply poor-quality sample rate conversion and/or truncation. Fortunately these problems can be eliminated with the selection of a good frequency-agile media player.

Many disk players also downsample all sources to 44.1/16. This processing can do significant damage to the audio quality.

The sample-rate and word-length displays on the DAC3 confirm the proper operation of your disk player, media player, and computer.

Bi-Directional 12 Volt Trigger

Benchmark has re-invented the 12 volt trigger. The trigger connection on the DAC3 can be used as an input or output or both, and is compatible with any common 12 volt trigger input or output. The trigger can be used to turn a power amplifier on or off automatically. The DAC3 will also respond to a 12 volt trigger and follow the actions of another audio component.

Benchmark components can communicate bidirectionally on the trigger I/O ports. This bidirectional communication provides greater flexibility. In a given system, the power button on any Benchmark device can be used to start or stop the entire audio system in a sequenced manner.

Distributed Power Regulation

To achieve the lowest possible noise, the DAC3 uses distributed power supply regulation. Each critical subsystem has at least one dedicated low-noise voltage regulator.

We have created a discrete ultra low-noise regulator for the ES9028PRO D/A converter. This Benchmark exclusive feature improves the noise performance of the already-outstanding ES9028PRO.

HPA2 ^TM Headphone Amplifier

The DAC3 headphone output is driven by Benchmark's signature HPA2™ headphone power amplifier. This high-current, high-output amplifier has an output impedance that is nearly 0 Ohms. It is designed to drive loads as low as 30 Ohms without any increase in distortion. It also has sufficient amplitude to drive low-sensitivity 600-Ohm headphones.

The HPA2 ^™ includes current-limiting circuits that fully protect against damage from short circuits. This is important because the right channel of a headphone amplifier will experience a short whenever a mono phone plug is inserted into the stereo headphone jack. Shorts may also occur when a plug is partially inserted.

"0-Ohm" Output Impedance

Most headphone amplifiers use series resistors to maintain stability and protect against short-circuit conditions. These resistors are usually at least 30 Ohms, and have a negative impact on performance. A headphone amplifier with series resistors may measure very well on a test bench when driving resistive loads. However, the same amplifier will measure very poorly when driving a headphone load. Unfortunately, most manufacturers do not measure or specify headphone amplifier performance

when loaded with real headphones. The measurements use ideal resistive loads. Our measurements show that headphones do not behave like resistive loads.

Headphone Performance

In our tests we have measured substantial distortion across resistors that are wired in series with headphones. We have conducted measurements with a variety of headphones. In general, distortion increases as headphone impedance decreases. This distortion can be eliminated with a properly designed "0-Ohm" headphone amplifier.

The performance of the HPA2 ^™ does not change when headphones are driven. THD+N measurements for no-load, 30-Ohm resistive loads, 30-Ohm headphone loads, and 600-Ohm headphone loads are virtually identical. The HPA2 ^™ will substantially improve the sound of 30 and 60-Ohm headphones. It will make very noticeable improvements with 600-Ohm headphones.

Differential Amplifiers

Differential amplifiers remove common-mode distortion components from the D/A converter outputs. This feature is critical for achieving low-distortion in down-stream devices. Benchmark addresses common-mode distortion so that it will not cause distortion in power amplifiers and other connected devices. Common-mode distortion can cause audible distortion while escaping the scrutiny of an audio analyzer. The balanced and unbalanced outputs on the DAC3 deliver very similar performance.

Many D/A converters omit the differential amplifiers after the converters. Specifications usually ignore common-mode distortion. A balanced signal with high common-mode distortion can measure just fine when feeding a precisely balanced input on a high-quality audio analyzer. However, any imbalance in a downstream device will expose the common-mode distortion.

Jitter-Immune UltraLock3 ^TM

UltraLock3 ^TM is an improved version of the UltraLock2 ^TM clock system used in the DAC2. The new UltraLock3 ^TM system provides faster lock times than the older UltraLock2 ^TM and UltraLock ^TM systems. The DSP processing is 32-bits, DSP headroom is 3.5 dB, sample rate is 211 kHz, and jitter-induced distortion and noise is at least 160 dB below the level of the music - well below the threshold of hearing. Benchmark's UltraLock3 ^TM system eliminates all audible jitter artifacts.

The Importance of Eliminating Jitter

Accurate 24-bit audio conversion requires a very low-jitter conversion clock. Jitter can very easily turn a 24-bit converter into a 16-bit converter (or worse). There is no point in buying a 24-bit converter if clock jitter has not been adequately addressed.

Jitter is present on every digital audio interface. This type of jitter is known as 'interface jitter' and it is present even in the most carefully designed audio systems. Interface jitter accumulates as digital signals travel down a cable from one digital device to the next. If we measure interface jitter in a typical system we will find that it is 10 to 10,000 times higher than the maximum allowable level for accurate 24-bit conversion. Fortunately, interface jitter has absolutely no effect on the audio unless it influences the conversion clock in an analog-to-digital converter (A/D), the conversion clock in a digital-to-analog converter (D/A), or the rate estimator in an asynchronous sample rate converter (ASRC).

Many converters use a single-stage Phase Lock Loop (PLL) circuit to derive their conversion clocks from AES/EBU, wordclock, or superclock reference signals. Single-stage PLL circuits provide some jitter attenuation above 5 kHz but none below 5 kHz. Unfortunately, digital audio signals often have their strongest jitter components at 2 kHz. Consequently, these converters can achieve their rated performance only when driven

from very low jitter sources and through very short cables. It is highly unlikely that any converter with a single-stage PLL can achieve better than 16 bits of performance in a typical installation. Specified performance may be severely degraded in most installations.

Better converters often use a two-stage PLL circuit to filter out more of the interface jitter. In theory, a two-stage PLL can remove enough of the jitter to achieve accurate 24-bit conversion (and some do). However, not all two-stage PLL circuits are created equal. Many two-stage PLLs do not remove enough of the low-frequency jitter. In addition, two-stage PLL circuits often require several seconds to lock to an incoming signal. Two-stage PLL circuits may fail to lock when jitter is too high, or when the reference sample frequency has drifted.

UltraLock ^TM converters exceed the jitter attenuation performance of two-stage PLL converters while achieving near instantaneous lock time. They are free from the slow-lock and no-lock problems that can plague two-stage PLL designs. UltraLock ^TM converters have extremely high immunity to interface jitter under all operating conditions.

The UltraLock ^TM system is so effective that no jitter-induced artifacts could be detected using an Audio Precision System 2 Cascade test set while the inputs to the DAC3 were exposed to high levels of interface jitter. The measurement limits included the ability to detect artifacts as low as -144 dBFS, but none could be detected, even while applying jitter amplitudes as high as 12.75 UI, over a frequency range of 2 Hz to 200 kHz. Any AES/EBU signal that can be decoded by the AES/EBU receiver in the DAC3 will be reproduced without the addition of any measurable jitter artifacts.

Benchmark's UltraLock™ technology eliminates jitter-induced performance problems. UltraLock™ technology isolates the conversion clock from the digital audio interface clock. Jitter on a D/A digital audio input, or an A/D reference input can never have any measurable effect on the conversion clock of an UltraLock ^TM converter. In an UltraLock ^TM converter, the conversion clock is never phase-locked to a reference clock. Instead the converter oversampling-ratio is varied with extremely high precision to achieve the proper phase relationship to the reference clock. The clock isolation of the UltraLock ^TM system ensures that interface jitter can never degrade the quality of the audio conversion. Specified performance is consistent and repeatable in any installation with cables of any quality level!

How does conversion clock jitter degrade converter performance?

Problem #1: Jitter phase-modulates the audio signal. This modulation creates sidebands (unwanted tones) above and below every tone in the audio signal. Worse yet, these sidebands are often widely separated from the tones in the original signal.

Jitter-induced sidebands are not musical in nature because they are not harmonically related to the original audio. Furthermore, these sidebands are poorly masked (easy to hear) because they can be widely separated above and below the frequencies of the original audio tones. In many ways, jitter induced distortion resembles intermodulation distortion (IMD). Like IMD, jitter induced distortion is much more audible than harmonic distortion, and more audible than THD measurements would suggest.

Jitter creates ‘new audio’ that is not harmonically related to the original audio signal. This ‘new audio’ is unexpected and unwanted. It can cause a loss of imaging, and can add a low and mid frequency ‘muddiness’ that was not in the original audio.

Jitter-induced sidebands can be measured using an FFT analyzer while the converter plays a pure high-amplitude tone. We typically use a full-scale 10 kHz test tone to test for the presence of jitter-induced side bands (see Graph 16). This FFT shows that the DAC3 is free from any jitter-induced sidebands to a measurement limit of about -144 dB relative to the level of the test tone.

The graph plots the output spectrum of the DAC3 when exposed to 31 different jitter frequencies ranging from 100 Hz to 100 kHz. All 31 output spectra are identical and are free from any signs of jitter-induced distortion.

Problem #2: Jitter can severely degrade the anti-alias filters in an oversampling converter. This is a little known but easily measurable effect. Most audio converters operate at high oversampling ratios. This allows the use of high-performance digital anti-alias filters in place of the relatively poor performing analog anti-alias filters. In theory, digital anti-alias filters can have extremely sharp cutoff characteristics, and very few negative effects on the in-band audio signal. Digital anti-alias filters are usually designed to achieve at least 100 dB of stop-band attenuation. But, digital filters are designed using the mathematical assumption that the time interval between samples is a constant. Unfortunately, sample clock jitter in an A/D or D/A varies the effective time interval between samples. This variation alters the performance of these carefully designed filters. Small amounts of jitter can severely degrade stop-band performance, and can render these filters useless for preventing aliasing.

The obvious function of a digital anti-alias filter is the removal of audio tones that are too high in frequency to be represented at the selected sample rate. The not-so-obvious function is the removal of high-frequency signals that originate inside the converter box, or even originate inside the converter IC. These high-frequency signals are a result of crosstalk between digital and analog signals, and may have high amplitudes in a poorly designed system. Under ideal (low jitter) conditions, the digital anti-alias filter may remove most of this unwanted noise before it can alias down into lower (audio) frequencies. These crosstalk problems may not become obvious until jitter is present.

Stop-band attenuation can be measured very easily by sweeping a test tone between 24 kHz and at least 200 kHz while monitoring the output of the converter.

Put UltraLock ^TM converters to the test:

We encourage our customers to perform the above tests on UltraLock ^TM converters (or let your ears be the judge). There will be absolutely no change in performance as jitter is added to any digital input on an UltraLock ^TM converter. Try the same tests on any converter using conventional single or two-stage PLL circuits. Tests should be performed with varying levels of jitter and with varying jitter frequencies. The results will be very enlightening. Jitter related problems have audible (and measurable) effects on A/D and D/A devices. Practitioners of Digital Audio need to understand these effects.

Is it possible to eliminate all of the effects of jitter in an entire digital audio system?

Interface jitter will accumulate throughout even the most carefully designed digital audio system. Fortunately, interface jitter can only degrade digital audio if it affects the sampling circuit in an analog-to-digital or digital-to-analog converter. Any attempt to cure jitter outside of an A/D or D/A will prove expensive and, at best, will only partially reduce jitter-induced artifacts. Dedicated clock signals (word clock, and super clock, etc.) are often distributed to A/D converters and D/A converters in an attempt to reduce jitter. Again, these are only partial solutions because jitter even accumulates in these clock distribution systems. Furthermore, a poor quality master clock generator can degrade the performance of the entire system (if converter performance is dependent upon reference clock quality). Jitter-free A/D and D/A converters are the only true insurance against the ill effects of jitter. UltraLock™ converters are jitter-immune under all operating conditions (they will never add audible jitter-induced artifacts to an audio signal).

What UltraLock ^TM converters cannot do:

UltraLock™ converters cannot undo damage that has already been done. If an A/D with a jitter problem was used to create a digital

audio signal, then there is nothing that can be done to remove the jitter-induced distortion that happened inside the A/D converter. Jitter-induced sidebands are extremely complex and cannot be removed with any existing audio device. Therefore, it is very important to attack jitter at both ends of the audio chain. The DAC3 is a great start, as it will allow accurate assessment of various A/D converters. It is impossible to audibly evaluate A/D performance without a good D/A. The consistent performance delivered by the DAC3 eliminates one major variable - jitter.

Multi-Mode Asynchronous USB Audio

Plug it in and Start Listening... Immediately

Benchmark's Advanced USB Audio system supports the industry standard USB Audio 1.1 and USB Audio 2.0 protocols. These audio protocols should not be confused with USB port speeds. The USB Audio 1.1 protocol requires at least a USB 1.0 (Full Speed) port. USB Audio 2.0 requires at least a USB 2.0 (High Speed) port.

Benchmark's USB Audio 1.1 and USB Audio 2.0 modes are frequency agile. This means that the sample rate is controlled by the computer. The DAC3 will follow sample rate changes initiated by the computer and/or the media playback software.

Tip: The USB Audio 1.1 protocol will run on any USB port, but if it is run on a USB 1.0 (Full Speed) port, it will require all of the available bandwidth to support 96 kHz sample rates. If a USB 1.0 port is the fastest port available, make sure that there are no other devices sharing the USB hub that services the port. When possible, connect the DAC3 to a port that supports USB 2.0 or higher.

Tip: The USB Audio 2.0 protocol is required for sample rates above 96 kHz. This protocol will not run on USB 1.0 ports. When possible, connect the DAC3 to a port that supports USB 2.0 or higher.

Asynchronous USB

In all modes the USB communications are asynchronous. An ultra low jitter conversion clock is generated inside the DAC3. The asynchronous USB interface pulls data from the computer without using computer-generated clocks. The D/A conversion in the DAC3 is completely isolated by the asynchronous USB interface and by the UltraLock3 ^TM jitter-attenuation system.

The DAC3 has a low-jitter master clock which controls the transfer of audio data from the computer to the USB sub-system. The computer asynchronously transfers audio data to a buffer in the DAC3. The contents of the buffer are then asynchronously transferred to the D/A conversion sub-system. This second asynchronous transfer eliminates any traces of jitter that accumulate as the data is transferred between the USB and conversion subsystems. No traces of jitter-induced distortion are detectable at our measurement limits (about -144 dBFS). This truly represents the state-of-the-art. Enjoy the convenience of computer playback without compromise.

The Asynchronous USB system supports USB Audio 2.0 for high-resolution 192kHz, and DSD playback. No drivers are required for MAC operating systems. An easy-to-install driver adds 192 kHz and DSD capabilities to Windows operating systems.

The asynchronous driverless USB Audio 1.1 mode supports sample rates up to 96 kHz. This USB mode can be selected from the front panel or from the remote control. The driverless USB Audio 1.1 mode allows quick plug-and-play connections to Windows, MAC, iOS, and Linux operating systems without installing drivers. Just plug in the USB, and the DAC3 becomes an available audio device. In many cases, audio will automatically be routed to the newly connected device. If not, it can be selected as the current or default playback device.

The industry-standard USB Audio Mode 2.0 mode is not yet natively supported by the

current Windows operating systems. For this reason, a driver is required for Windows operating systems. The driver supports Windows XP, Vista, or 7, 8 and 10. This driver is required for DSD and sample rates above 96 kHz when using Windows.

The USB subsystem is computer powered (through the USB cord) and it remains active

when the DAC3 is powered down. This feature prevents interruptions to the computer playback operations and eliminates the need to reconfigure the computer every time the converter is turned on.

The Windows USB Audio 2.0 driver is available at:

BenchmarkMedia.com/drivers

USB Driver Installation

Windows Operating Systems

Note: The DAC2/ DAC3 driver is available for download at: BenchmarkMedia.com/drivers

Note: To provide full backward and forward compatibility, the DAC3 uses the DAC2 USB drivers. This prevents the need to install two different sets of drivers. Please note that the DAC3 USB input will be identified as "Benchmark DAC2" in your computer control panels. This is intentional.

Before you install the driver, make sure the USB cable is unplugged.

1. In the DAC2 Driver folder, double click "setup.exe."

1. A welcome screen will pop-up. Click "Next."

1. When you see the following screen, turn on the DAC3, plug in the USB cable, and select the USB input on the DAC3. By default, the DAC3 is shipped in USB Audio 1.0 mode. Do not proceed to the next step until the USB Audio 2.0 mode has been enabled. You can enable the USB Audio 2.0 mode using one of the following two methods:

- METHOD 1 - REMOTE CONTROL: Using your remote control, press and hold USB button for 3 seconds (the 4X light should flash once). If the 2X light flashes instead of the 4X light, repeat this step.

- METHOD 2 - FRONT PANEL: From the front panel, simultaneously press and hold both INPUT buttons for three seconds (the 4X light should flash once). If the 2X light flashes instead of the 4X light, repeat this step.

1. You will now be prompted to select a location to install the driver. It will default to your Program Files folder. If you wish to install it another location, you can change the location. We suggest keeping it in the default location. Click "Install".

1. When the installation begins you will see the following screen. Please be patient while the driver installs. Installation may require several minutes.

1. When the installation finishes a message at the top will say "Installation Complete." Click "Next" to continue.

1. Click "Finish." The Setup will close automatically. This completes the installation process. You can now enjoy music over the USB Audio 2.0 connection at sample rates up to 192 kHz. DSD can also be played in DoP 1.1 format.

Performance Graphs

Audio Precision

DAC3 - FFT Idle Channel Noise at Max Gain, 0 dBr = 0 dBFS = 27.5 dBu

Sweep	Trace LineStyle			Thick	Data	Axis	Comment
1	1	Green Solid		4	Flt.Ch.1	Ampl Left
1	2	Red	Solid	4	Flt.Ch.2	Ampl Right

DAC3 - FFT Idle Channel Noise.at27

Graph 1 - FFT Idle Channel Noise

The extraordinary performance of the DAC3 is demonstrated by the FFT plot shown above. There is no sign of any AC hum, there are no idle tones, and there are no spurious tones detected at a measurement limit of -160 dBFS.

The rise at 0 Hz is normal in an FFT analysis and is not an indication of noise. This 32k point FFT analysis uses a Blackman-Harris window with 16x power averaging, and spans a frequency range of DC to 32 kHz.

Sweep Trace Line				Thick Data Axis			Comment Cursor1 Cursor2
1	1	Green	Solid	4	Ft.Ch.1 Ampl	Left	Left Channel *-160.182 dBr *-158.092 dBr
1	2	Red	Solid	4	Ft.Ch.2 Ampl	Right	Right Channel -159.850 dBr A	-160.611 dBr A

DAC3 - FFT Idle Channel Noise - Low Frequency.at27

Graph 2 - Low Frequency FFT - AC Line-Related Hum

The DAC3 shows no evidence of AC line-related hum to a measurement limit of about -160 dBFS. The cursors are placed at 60 Hz and 180 Hz (frequencies where we would expect to see interference from the 60 Hz AC input. In the idle channel noise spectrum there is absolutely no sign of any AC hum! At full output, these line-related frequencies still measure better than -133 dB (see Graph 4).

This graph demonstrates one of the advantages of switching power supplies. The switching power supplies in the DAC3 operate at frequencies above the audio band and this eliminates the strong line-frequency magnetic fields that would have been created by line-frequency power transformers.

	Trace	Color	Sw	Lape Style	Thick	Data	Axis	Comment	Source 2	Cursor1	Cursor2
1	2	Green	Solid	4	Ft.Ch.1	Ampl	Left		:1.00000 =Swr.Ch. A Input	*-111.013 dBr	*-124.989 dBr
2	2	Red	Solid	4	Ft.Ch.1	Ampl	Left		:2.00000 =Swr.Ch. A Input	-111.241 dBr A	-127.362 dBr A

DAC3 - FFT 10 kHz.at27

Graph 3 - FFT 10 kHz

The 10 kHz FFT analysis is an excellent test for detecting sample clock jitter. Jitter will create sidebands (unwanted tones) above and below the 10 kHz test tone. For example, a jitter frequency of 1 kHz would create two sideband tones; a lower sideband at 9 kHz, and an upper sideband at 11 kHz. Similarly, a jitter frequency of 2 kHz would produce sideband tones at 8 kHz and 12 kHz. The above plot shows no evidence of jitter-induced sidebands to a measurement limit of about -149 dB relative to the amplitude of the 10 kHz test tone.

Note the very low harmonic distortion; the 2nd harmonic (20 kHz) measured -111 dB, and the 3rd harmonic (30 kHz) measured -125 to -127 dB.

This 32k point FFT analysis uses a Blackman-Harris window with 16x power averaging. The 10 kHz fundamental has been removed by a notch filter in order to increase the resolution of the A/D converter in the AP2722 test set.

	Trace Li6o8Sr3weep		Thick Data	Axis	Comment	Source 2 Cursor1	Cursor2
1	2	Green Solid	4 Ft.Ch.1 Ampl Left		Left Channel : 1.00000 =Swr.Ch. A Input	-125.680 dBRA -123.514 dBRA
2	2 Red	Solid 4	Ft.Ch.1 Ampl	Left Right Channel : 2.00000 =Swr.Ch. A Input	*139.647 dBRA *122.546 dBRA

DAC3 - FFT 1 kHz.at27

Graph 4 - FFT 1 kHz

The 1 kHz FFT analysis demonstrates the very low harmonic distortion of the DAC3. The second harmonic distortion (2 kHz) measured better than -126 dB, while the 3rd harmonic distortion measured better than -122 dB relative to the amplitude of the 1 kHz test tone.

This 32k point FFT analysis uses a Blackman-Harris window with 16x power averaging. The 1 kHz fundamental has been removed by a notch filter in order to increase the resolution of the A/D converter in the AP2722 test set.

Note that under this full-output condition, the AC line-related hum frequencies (60 Hz, 180 Hz, and 240 Hz) measure better than -133 dB.

Sweep	Trace	Color	Line Style	Thick	Data	Axis	Comment	Cursor1	Cursor2
1	1	Red	Solid	4	Anlr.Level A	Left		*-0.015 dBr	*-0.031 dBr

DAC3 - Frequency Response.at27

Graph 5 - Frequency Response

This plot demonstrates the ruler-flat frequency response of the DAC3. Note that the frequency response measures - 0.015 dB at 10 Hz and -0.031 dB at 40 kHz. The extreme low-frequency extension of the DAC3 virtually eliminates the phase shifts that often occur at low frequencies (near 20 Hz). Bass is rendered in the proper timing relative to high-frequency content.

Audio Precision

DAC2 - Differential Phase

Fs = 96 kHz

Sweep Trace Line Goyte				Thick Data Axis Comment				Cursor1 Cursor2
1	1	Green	Solid	4	Anlr.Phase	Left	Left to Right	^*+0.24 deg	^*+0.42 deg
2	1	Red	Solid	4	Anlr.Phase	Left	Right to Left	-0.25 deg	-0.43 deg

DAC3 - Differential Phase.at27

Graph 6 - Differential Phase

This plot demonstrates the inter-channel phase accuracy of the DAC3. This is a highly expanded scale, spanning only +/- 1 degree at 45kHz . From this plot, the inter-channel phase accuracy is calculated to be +/- 0.25 degrees at 20kHz , and +/- 0.43 degrees at 40kHz .

The phase accuracy of the DAC3 approaches the phase accuracy of the Audio Precision AP2722 test set. For this reason, the phase error in the AP must be subtracted from the measurement. The green trace assigns the left channel to channel 1 of the AP, and the right channel to channel 2 of the AP. The red trace reverses the inputs. The two traces must be averaged to remove the phase errors of the AP test set.

DAC3 converters are phase-accurate between boxes. Three DAC3 converters can be used as a group to form a phase-accurate 5.1 surround system. Four DAC3 converters can be combined to form a 7.1 system. The phase accuracy between any two channels will match the typical phase accuracy shown above.

	Trace	Color	Wideep Style	Thick	Data	Avis	Comment
1	1 Red	Solid	4	Distortion,Ch.1 Harm Sum1	Left	THD
1 2 Black		Solid 4		Anir.THD+N Ampl Right		THD+N

DAC3 - THD and THD+N vs Amplitude.at27

Graph 7 - THD and THD+N vs. Amplitude (Balanced Outputs)

These plots demonstrate the very low harmonic distortion produced by the DAC3 with digital input signal levels ranging from -30 dBFS to 0 dBFS. These plots show that THD should never reach the threshold of hearing in most listening environments. This is proof that the DAC3 is virtually uncolored by any traces of harmonic distortion.

The black curve is a plot of THD+N, band limited to 22 kHz, and was acquired using the analog analyzer in the AP2722 test set. The red curve is a plot of THD (harmonic distortion only) and was acquired using the analog notch filter, A/D converter, and digital harmonic distortion analyzer in the AP2722 test set. This THD curve includes all harmonics falling below 32 kHz. The steps near -3 dBFS and -9 dBFS are due to the auto ranging of the AP2722 test set and are an indication that the THD performance of the DAC3 is very close to the measurement limits of the AP2722.

	Trace	Color	S widely Style	Thick	Data	Axis	Comment
1	1 Red	Solid	4	Distortion. Ch.1 Harm Sum1 Anlr. THD+N Ampl Right		Left	THD Only
1 2 Black		Solid 4					THD+N

DAC3 - THD and THD+N vs Amplitude Unbalanced.at27

Graph 8 - THD and THD+N vs. Amplitude (Unbalanced Outputs)

This plot shows the THD and THD+N performance of the unbalanced outputs.

Note that the THD performance of the unbalanced outputs approaches that of the balanced outputs. The THD+N levels are slightly higher on the unbalanced outputs. This is due to the relatively low (2 Vrms) signal levels used on unbalanced interfaces. This noise difference highlights one advantage of professional-level balanced interconnects.

	Trace	Color	Sweep	Style	Thick	Data	Axis	Comment Source 2
1	3	Black	Solid	4	Distortion.Ch.1	Harm Sum1	Right	THD Balanced Output : 2.00000 =Swr.Ch. A Input
2	2	Red	Solid	4	Distortion.Ch.1	Harm Sum1	Left	THD Unbalanced	Out-Swr.Ch. A Input

DAC3 - THD vs Amplitude Balanced vs Unbalanced.at27

Graph 9 - THD vs. Amplitude - Balanced vs. Unbalanced Outputs

This plot demonstrates that the balanced and unbalanced analog outputs on the DAC3 have very similar THD performance. The unbalanced outputs (red curve) closely match the performance of the balanced outputs (black curve) at high signal levels. The separation between the curves at signal levels below -10 dBFS is due to the improved SNR provided by the balanced interfaces. At 0 dBFS, the balanced interfaces were calibrated to +24 dBu (12.28 Vrms) while the unbalanced interfaces were calibrated to +8.24 dBu (2 Vrms). The higher signal levels used with the balanced interfaces make it easier to achieve high signal to noise ratios. This is just one reason why Benchmark recommends balanced interconnects.

The DAC3 includes differential amplifiers that remove common-mode THD from the balanced outputs of the SABRE-PRO converters. These differential amplifiers give the unbalanced outputs the ability to approach the THD performance of the balanced outputs. Please note that the differential amplifiers also eliminate common-mode distortion on the balanced outputs.

Top-quality D/A conversion chips (such as the ES9028PRO) are equipped with balanced outputs. These balanced outputs allow a significant reduction of THD if they are followed by precision differential amplifiers. Conversion chips tend to produce significant common-mode distortion products that should be removed by a differential amplifier. The DAC3 includes precision differential amplifiers following the outputs of the ES9028PRO. Many competing products omit these differential amplifiers. The omission of the differential amplifiers would make the THD much higher on the unbalanced outputs. The differential amplifiers also improve the system performance when the balanced outputs are driving balanced inputs that are not precisely trimmed.

The THD measurements shown above confirm the effectiveness of the differential amplifiers in the DAC3. Additional confirmation can be obtained by measuring the THD of either side of the balanced outputs relative to ground.

Audio Precision

DAC3 - Headphone Amplifier - THD+N vs Power at 1 KHZ (w/20 kHz LPF unweighted) Headphone outputs into 300 Ohms, both channels driven

	Trace	ColorSwIsep Style	Thick	Data	Axis	Comment	Cursor1	Cursor2
1	1	Red Solid	4	AnIr.THD+N Ratio	Left		^* -80.976 dB	^* -102.254 dB

DAC3 - HEADPHONE - THD+N vs Power - 300 Ohm Load.at27

Graph 10 - Headphone Amplifier into 300 Ohms - THD+N versus Power

This plot shows the THD+N performance of the headphone outputs when driving a typical 300-Ohm load. Note that the THD+N performance of the headphone outputs approaches that of the balanced outputs (-110 dB at 20 mW). Benchmark's HPA2 ^TM headphone amplifier can cleanly deliver 21.5 dBu (9.2 Vrms) into a 300-Ohm load.

This graph shows that the HPA2 ^TM has the voltage required to drive high-impedance headphones. The following graph shows that the HPA2 ^TM has the power required to drive low-impedance headphones. In either case, the near 0-Ohm output impedance provides outstanding control and damping of the headphone drivers.

The HPA2 ^TM includes 3 jumper-programmable gain ranges that can be configured to match the voltage sensitivity of your favorite headphones. The gain-range settings do not change the output impedance or the THD of the headphone amplifier.

Audio Precision

DAC3 - Headphone Amplifier - THD+N vs Power at 1 KHZ (w/20 kHz LPF unweighted) Headphone outputs into 30 Ohms, both channels driven

		ColorSwase Style		Thick	Data	Axis	Comment	Cursor1 Cursor2
1	1	Red	Solid	4	Anlr.THD+N Ratio	Left		*-80.867 dB	*-87.006 dB

DAC3 - HEADPHONE - THD+N vs Power - 30 Ohm Load.at27

Graph 11 - Headphone Amplifier into 30 Ohms - THD+N versus Power

This plot shows the THD+N performance of the headphone outputs under a very heavy load (30-Ohms). Note that the THD+N performance of the headphone outputs still approaches that of the balanced outputs (-110 dB at 20 mW).

This graph demonstrates that Benchmark's HPA2 ^TM headphone amplifier can cleanly deliver 1.25 W into 30 Ohms, both channels driven.

Sweep	Trace	Color	Line Style	Thick	Data Axis	Comment
1	1	Green	Solid	4	Anlr.THD+N Ratio Left	Left Channel
1	2 Red		Solid 4		Anlr.THD+N Ratio Left	Right Channel

DAC3 - THD+N vs FREQUENCY 80kHz.at27

Graph 12 - THD+N vs. Frequency 80 kHz

The analog output stages on the DAC3 have high slew rates and are capable of maintaining low THD levels at high frequencies even when driven to 0 dBFS. Note that the THD+N remains very low at 20 kHz, even when operating at maximum output levels.

Audio Precision
DAC3 - THD and THD+N vs. Frequency, 1 kHz, 0 dBFS, 24 dBu Digital In to Balanced Analog Out

	Trace	Color	S widely	Style	Thick	Data	Axis	Comment Cursor1	Cursor2
1	1	Black	Solid	4	Anlr.THD+N Ampl Left			THD+N, 80 kHz LPF-109.838 dBr A -107.584 dBr A
1	2	Red	Solid		4 Distortion.Ch.1 Harm Sum1		Right	THD, 48 kHz LPF*-117.274 dBr *-111.274 dBr

DAC3 - THD and THD+N vs Frequency Digital to Analog.at27

Graph 13 - THD and THD+N vs. Frequency

These plots demonstrate that the harmonic distortion of the DAC3 is lower than the THD+N numbers would suggest. This black curve is a plot of THD+N. The red curve is a plot of THD only. Below about 10 kHz, the THD is so low that the THD+N measurement is dominated by noise.

Audio Precision
DAC3 - THD+N vs Sample Rate, 1 kHz at 0 dBFS (w/20 kHz LPF unweighted)

Sweep	Trace	Color	Line Style	Thick	Data Axis	Comment	Cursor1	Cursor2
1	1	Green	Solid	4	Anlr.THD+N Ratio Left	Left Channel	-113.043 dB	-113.041 dB
1	2	Red	Solid	4	Anlr.THD+N Ratio Left	Right Channel	*-113.209 dB	*-113.208 dB

DAC3 - THD+N vs Sample Rate.at27

Graph 14 - THD+N versus Sample Rate

The THD+N performance of the DAC3 is identical at all Sample Rates.

Trace Line Style Break Data			Axis Comment
1	1 Red Solid 4		Anlr.THD+N Ratio Left
1	2	Black Solid 4 Dio.Interface Jitter	Right

DAC3 - JITTER TOLERANCE.at27

Graph 15 - Jitter Tolerance

The Audio Engineering Society (AES) has created a jitter tolerance template for testing digital audio devices. The black curve shows the AES jitter tolerance template (see right-hand vertical axis). Induced jitter approaches 5 UI at 200 Hz, and is reduced to 0.125 UI above 8 kHz. The red trace shows the THD+N of the DAC3 (left-hand vertical axis) while being driven with the jitter shown on the black curve. Over the entire range of the AES jitter tolerance test, the THD+N performance of the DAC3 is unchanged. The DAC3 easily passes the AES jitter tolerance test, and it does so without any performance degradation.

		ColorSweetLitterStyle		Thick	Data	Axis	Comment	Source 2
1	2 Blue		Solid	1	Ft.Ch.1 Ampl	Left		:100.000 Hz=Dio.Jitter Freq
2	2 Cyan		Solid	1	Ft.Ch.1 Ampl	Left		:125.893 Hz=Dio.Jitter Freq
3	2	Green	Solid	1	Ft.Ch.1 Ampl	Left : 158.489 Hz=Dio.Jitter Freq
4	2	Yellow	Solid 1		Ft.Ch.1 Ampl Left			:199.526 Hz=Dio.Jitter Freq
5	2 Red Solid			1 Ft.Ch.1 Ampl		Left : 251.189 Hz=Dio.Jitter Freq
6	2	Magenta Solid		1	Ft.Ch.1 Ampl Left			:316.228 Hz=Dio.Jitter Freq
7	2	Blue	Solid	1	Ft.Ch.1 Ampl	Left		:398.107 Hz=Dio.Jitter Freq
8	2	Cyan	Solid	1	Ft.Ch.1 Ampl	Left		:501.187 Hz=Dio.Jitter Freq
9	2	Green	Solid	1	Ft.Ch.1 Ampl	Left		:630.957 Hz=Dio.Jitter Freq
10	2 Yellow		Solid	1	Ft.Ch.1 Ampl	Left		:794.328 Hz=Dio.Jitter Freq
11	2	Red	Solid	1	Ft.Ch.1 Ampl	Left		:1.00000 kHz=Dio.Jitter Freq
12	2	Magenta	Solid	1	Ft.Ch.1 Ampl	Left		:1.25893 kHz=Dio.Jitter Freq
13	2	Blue	Solid	1	Ft.Ch.1 Ampl	Left		:1.58489 kHz=Dio.Jitter Freq
14	2	Cyan	Solid 1		Ft.Ch.1 Ampl Left : 1.99526 kHz=Dio.Jitter Freq
15	2	Green	Solid	1	Ft.Ch.1 Ampl Left : 2.51189 kHz=Dio.Jitter Freq
16	2	Yellow	Solid	1	Ft.Ch.1 Ampl	Left		:3.16228 kHz=Dio.Jitter Freq
17	2	Red	Solid	1	Ft.Ch.1 Ampl	Left		:3.98107 kHz=Dio.Jitter Freq
18	2	Magenta	Solid	1	Ft.Ch.1 Ampl	Left		:5.01187 kHz=Dio.Jitter Freq
19	2 Blue		Solid	1	Ft.Ch.1 Ampl	Left		:6.30957 kHz=Dio.Jitter Freq
20	2	Cyan	Solid	1	Ft.Ch.1 Ampl	Left : 7.94328 kHz=Dio.Jitter Freq
21	2	Green	Solid	1	Ft.Ch.1 Ampl	Left		:10.0000 kHz=Dio.Jitter Freq
22	2	Yellow	Solid 1		Ft.Ch.1 Ampl Left : 12.5893 kHz=Dio.Jitter Freq
23	2	Red	Solid	1	Ft.Ch.1 Ampl	Left : 15.8489 kHz=Dio.Jitter Freq
24	2 Magenta Solid			1	Ft.Ch.1 Ampl	Left		:19.9526 kHz=Dio.Jitter Freq
25	2	Blue	Solid	1	Ft.Ch.1 Ampl	Left		:25.1189 kHz=Dio.Jitter Freq
26	2	Cyan	Solid	1	Ft.Ch.1 Ampl	Left		:31.6228 kHz=Dio.Jitter Freq
27	2	Green	Solid	1	Ft.Ch.1 Ampl	Left		:39.8107 kHz=Dio.Jitter Freq
28	2	Yellow	Solid	1	Ft.Ch.1 Ampl	Left		:50.1187 kHz=Dio.Jitter Freq
29	2	Red	Solid	1	Ft.Ch.1 Ampl	Left : 63.0957 kHz=Dio.Jitter Freq
30	2	Magenta	Solid	1	Ft.Ch.1 Ampl	Left		:79.4328 kHz=Dio.Jitter Freq
31	2	Blue	Solid	1	Ft.Ch.1 Ampl	Left : 100.000 kHz=Dio.Jitter Freq

DAC3 - JITTER TOLERANCE FFT.at27

Graph 16 - Jitter Tolerance FFT

This figure shows a series of FFTs that were acquired while running the AES jitter tolerance test. This is the ultimate jitter-immunity test.

Note that none of the 31 FFTs show any signs of jitter-induced sidebands. Note that the plots are identical to the plots shown in Graph 3.

The DAC3 shows no change in performance when the AES jitter tolerance test is applied to the digital inputs. No jitter-induced sidebands are visible anywhere in this measurement.

Please note that the 10 kHz fundamental needed to be notched out in order to make this very high-resolution measurement. If the fundamental was not notched out, the spurious tones, produced by the A/D converter in the AP2722 test set, would have obscured the virtually-perfect results.

Graph 17 - IMD 11k 12K

This plot demonstrates that the DAC3 has very low IMD distortion. The 1 kHz difference frequency measures -131 dB, and the 10 kHz and 13 kHz products measure about -125 dB. The actual IMD may be better. The results shown are partially limited by the performance of the AP2722 test set.

All IMD distortion products should be well below audible levels.

Specifications

Audio Performance
Fs = 44.1 to 96 kHz, 20 to 20 kHz BW, 1 kHz test tone, 0 dBFS = +24 dBu (unless noted)
SNR - A-Weighted, 0 dBFS = +27.5 dBu	128 dB
SNR - Unweighted, 0 dBFS = +27.5 dBu	126 dB
Dynamic Range - A-Weighted at maximum volume	128 dB
Dynamic Range - Unweighted at maximum volume	126 dB
THD+N, 1 kHz at 0 dBFS	-113 dBFS, -113 dB, 0.00022%
THD+N, 1 kHz at -1 dBFS	-114 dBFS, -113 dB, 0.00022%
THD+N, 1 kHz at -3 dBFS	-119 dBFS, -116 dB, 0.00016%
THD+N, 20 to 20 kHz sweep at -3 dBFS	-113 dBFS, -110 dB, 0.000032%
Frequency Response at Fs=192 kHz	+0 dB, -0.015 dB (20 to 20 kHz)-0.015 dB at 10 Hz-0.005 dB at 20 kHz-0.031 dB at 40 kHz-0.15 dB at 80 kHz
Frequency Response at Fs=48 kHz	+0 dB, -0.015 dB (20 to 20 kHz)-0.015 dB at 10 Hz-0.005 dB at 20 kHz
Crosstalk	-116 dB at 20 kHz-130 dB at 1 kHz-137 dB at 20 Hz
Maximum Amplitude of Jitter Induced Sidebands (10 kHz 0 dBFS test tone, 12.75 UI sinusoidal jitter at 1 kHz)	<-144 dB
Maximum Amplitude of Spurious Tones with 0 dBFS test signal	<-138 dB
Maximum Amplitude of Idle Tones	<-147 dB
Maximum Amplitude of AC line related Hum & Noise	<-133 dB
Inter-channel Differential Phase (Stereo Pair - any sample rate)	+/- 0.25 degrees at 20 kHz
Inter-channel Differential Phase (Between DAC3 Units Fs<110 kHz) Any sample rate.	+/- 0.25 degrees at 20 kHz
Maximum Lock Time after Fs change	6 ms
Soft Mute Ramp Up/Down Time	9.6 ms
Mute on Receive Error	Yes
Mute on Lock Error	Yes
Mute on Idle Channel	No
50/15 us De-Emphasis Enable	Automatic in Consumer Mode
De-Emphasis Method	Digital IIR
De-Emphasis Supported at	Fs = 32, 44.1, 48 kHz
Group Delay (Latency)
Delay – Digital Input to Analog Output (function of sample rate)	1.36 ms at 44.1 kHz
	1.27 ms at 48 kHz
	0.90 ms at 88.2 kHz
	0.82 ms at 96 kHz
	0.51 ms at 176.4 kHz
	0.47 ms at 192 kHz

Digital Audio Inputs
Number of Digital Inputs (switch selected)	5 (1 USB, 2 Optical, 2 Coaxial)
Number of Channels	2
Input Sample Frequency Range	28 to 210 kHz (Coaxial Inputs)28 to 96 kHz (Optical Inputs)44.1, 48, 88.2, 96, 176.4, 192 kHz (USB Input)
Maximum Input Word Length	24 bits
Digital Input Impedance	75 Ohms (Coaxial Inputs)
DC Blocking Capacitors on Digital Inputs	Yes (Coaxial Inputs)
Transient and Over-Voltage Protection on Digital Inputs	Yes (Coaxial Inputs)
Minimum Digital Input Level	250 mVpp (Coaxial Inputs)

Jitter Tolerance
(With no Measurable Change in Performance)	>12.75 UI sine, 100 Hz to 3 kHz
	>1.5 UI sine at 20 kHz
	>1.5 UI sine at 40 kHz
	>1.5 UI sine at 80 kHz
	>1.5 UI sine at 90 kHz
	>0.25 UI sine above 160 kHz
Jitter Attenuation Method	BenchmarkUltraLock3TM- all inputs
Balanced Analog Outputs
Number of Balanced Analog Outputs	2
Output Connector	Gold-Pin NeutrikTM male XLR
Output Impedance	60 Ohms (Attenuator off)425 Ohms (Attenuator = 10 dB)135 Ohms (Attenuator = 20 dB)
Analog Output Clip Point	+29 dBu
Factory Set Bypass Level (with 0 dBFS digital input)	+24 dBu (Attenuator = 0 dB)
Volume Control Range (with 0 dBFS digital input)	Off to +27.5 dBu (Attenuator off)Off to +17.5 dBu (Attenuator = 10 dB)Off to +7.5 dBu (Attenuator = 20 dB)
Output Level Variation with Sample Rate	< +/- 0.006 dB

Unbalanced Analog Outputs
Number of Unbalanced Analog Outputs	4
Output Connector	RCA
Output Impedance	30 Ohms
Analog Output Clip Point	+13.5 dBu (3.7 Vrms)
Factory-Set Home Theater Bypass Output Level (with 0 dBFS digital input)	+8.2 dBu (2 Vrms)
Output Level Range (with 0 dBFS digital input)	Off to +11.7 dBu (3 Vrms)
Output Level Variation with Sample Rate	< +/- 0.006 dB

HPA2TM Headphone Outputs
Number of Headphone Outputs	2
Output Connectors	1/4" TRS with switch on left-hand jack
Output Impedance	< 0.11 Ohms
Output Level Control	Stereo Control on Front Panel
Output Level Range (with 0 dBFS digital input)	Off to +21.5 dBu (9.2 Vrms)
Output Power	1.25 W into 30 Ohms
Maximum Output Current	250 mA
Overload Protection (independent per channel)	Current limited at 300 mA, Thermal
Bandwidth	>500 kHz, -0.35 dB at 200 kHz
THD+N at 20 mW	-108 dB (0.0004%) into 300 Ohms,-100 dB (0.0010%) into 30 Ohms
Unbalanced Analog Inputs
Number of Unbalanced Analog Inputs	4
Input Connector	RCA
Input Impedance	20 K Ohms
Analog Input Clip Point	+18.5 dBu (6.5 Vrms)
Input Sensitivity	+8.2 dBu (2 Vrms)
Bandwidth	>500 kHz, -0.6 dB at 200 kHz
THD+N (Analog to Analog, 2 Vrms in, +24 dBu out)	-110 dB (0.00032%)

Status Display
Indicators - Type and Location	16 LEDs on Front Panel
Selection/ Status Indication	1 – Dim/Mute1 - Polarity7 – Input1 – Bypass/Calibrated Output2 – Word length4 – Sample Rate

AC Power Requirements
Nominal Operating Range	100 – 240 VAC, 50 - 60 Hz
Min/Max Operating range	90 – 260 VAC, 47 - 63 Hz
Power	< 0.5 Watts Standby12 Watts Typical Program15 Watts Maximum
Fuses (2 required)	5x20 mm, 0.5 A 250 V Slo-Blo® Type

Dimensions
Form Factor	12 Rack Wide, 1 RU High
Depth behind front panel	8.5" (216 mm)
Overall depth including connectors	9.33" (237 mm)
Width	9.5" (249 mm)
Height	1.725" (44.5 mm)

Weight
DAC3 only	3 lb.
DAC3 with accessories and manual	4 lb.
Shipping weight	7 lb.

Regulatory Compliance

FCC and RoHS Compliance Statements

FCC Notice (U.S. Only)

NOTICE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.

This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions:

1. This device may not cause harmful interference.
2. This device must accept any interference received including interference that may cause undesired operation.

Instructions to Users: This equipment complies with the requirements of FCC (Federal Communication Commission) equipment provided that following conditions are met:

• RCA Digital Connections: Shielded 75-Ohm coaxial cable must be used.

NOTICE: Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.

RoHS Compliant Information

This statement clarifies Benchmark Media Systems, Inc. product compliance with the EU's (European Union) directive 2002/95/EC, or, RoHS (Restrictions of Hazardous Substances).

As of July 01, 2006, All Benchmark Media Systems, Inc. products placed on the European Union market are compliant (containing quantity limit weight less than or equal to 0.1% (1000 ppm) of any homogeneous Lead (Pb), Mercury (Hg), Hexavalent Chromium (Cr VI), and flame retardant Polybrominated Biphenyls (PBB) or Polybrominated Diphenyl Ethers (PBDE)).

Certificate of Conformity

Diversified T.E.S.T. Technologies, Inc. has tested the product to the current appropriate standards and finds that the product is in compliance with those requirements.

EMC Directive:

Generic Emissions Standard:

Product Specific Emissions:

Generic Immunity Standard:

Immunity:

2004/108/EC

EN 61000-6-3: 2007/A1:2011

EN 55011 Class A

EN 61000-6-1: 2007

EN 61000-4-2

EN 61000-4-3

EN 61000-4-6

Electrostatic Discharge

Radiated Susceptibility

Conducted Susceptibility

Manufacturer's Name:

Manufacturer's Address:

Product:

Model Number:

This Certificate of Compliance issued September 21, 2012 is valid for the test sample of the product specified above and that it conforms to the Directive(s) and Standard(s).

Signature:

Annelle Frierson

Vice President

Diversified T.E.S.T. Technologies, Inc.

4675 Burr Drive

Liverpool, NY 13088

Phone: [phone]

Fax: [phone]

Warranty Information

Benchmark 1-Year Warranty

The Benchmark 1-Year Warranty

Benchmark Media Systems, Inc. warrants its products to be free from defects in material and workmanship under normal use and service for a period of one year from the date of delivery.

This warranty extends only to the original purchaser. This warranty does not apply to fuses, lamps, batteries, or any products or parts that have been subjected to misuse, neglect, accident, modification, or abnormal operating conditions.

In the event of failure of a product under this warranty, Benchmark Media Systems, Inc. will repair, at no charge, the product returned to its factory. Benchmark Media Systems, Inc. may, at its option, replace the product in lieu of repair. If the failure has been caused by misuse, neglect, accident, or, abnormal operating conditions, repairs will be billed at the normal shop rate. In such cases, an estimate will be submitted before work is started, if requested by the customer.

Attempts to deliberately deface, mutilate, or remove the product's label will render this warranty void. Benchmark will not honor warranties for any products disingenuously purchased on the US or Canadian markets for export.

The foregoing warranty is in lieu of all other warranties, expressed or implied, including but not limited to any implied warranty of merchantability, fitness or adequacy for any particular purpose or use. Benchmark Media Systems, Inc. shall not be liable for any special, incidental, or consequential damages, and reserves the right to change this information without notice. This limited warranty gives the consumer-owner specific legal rights, and there may also be other rights that vary from state to state.

The Benchmark Extended 5-Year Warranty \*

Benchmark Media Systems, Inc. optionally extends the standard 1-year warranty to a period of five years from the date of delivery.

* For the extended warranty to become effective, the original purchaser must register the product at the time of purchase either by way of the enclosed registration card or through the product registration section of the Benchmark Media Systems, Inc. website. This optional warranty applies only to products purchased within the US and Canada and is extended only to the original purchaser.

Attempts to deliberately deface, mutilate, or remove the product's label will render this warranty void. Benchmark will not honor warranties for any products disingenuously purchased on the US or Canadian markets for export. The terms of the extended warranty are subject to change without notice. For products purchased outside the US and Canada, please refer to the Extended Two 2-Year International Warranty.

The Benchmark Extended 2-Year International Warranty \*\*

Benchmark Media Systems, Inc. optionally extends the standard 1-year warranty to a period of two years from the date of delivery.

** For the extended warranty to become effective, the original purchaser must register the product at the time of purchase either by way of the enclosed registration card or through the product registration section of the Benchmark Media Systems, Inc. website. This optional warranty applies only to products purchased outside the US and Canada and is extended only to the original purchaser.

Attempts to deliberately deface, mutilate, or remove the product's label will render this warranty void. Benchmark will not honor warranties for any products disingenuously purchased on the US or Canadian markets for export. The terms of the extended warranty are subject to change without notice. For products purchased in within the US and Canada, please refer to the Extended Five 5-Year Warranty.

Notes on Warranty Repairs

An RMA (return merchandise authorization) number, issued by our Customer Service Department, is required when sending products for repair.

They must be shipped to Benchmark Media Systems prepaid and preferably in their original shipping carton with the RMA number clearly visible on the exterior of the packaging. A letter should be included giving full details of the difficulty.

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Benchmark Media Systems, Inc.

All rights reserved.

Benchmark Media Systems, Inc.

Benchmark Media Systems, Inc.

203 East Hampton Place, STE 2

Syracuse, NY 13206

USA

PHONE: [phone]

FAX: [phone]

benchmarkmedia.com