Xonar Essence STU - Hi-Fi System ASUS - Free user manual and instructions

Product Type	External USB DAC & Headphone Amplifier
Model	Xonar Essence STU
Brand	ASUS
Dimensions (W x D x H)	130 x 120 x 50 mm
Weight	Approximately 300 g
Power Supply	USB powered, 5V DC
Audio Resolution	Up to 24-bit / 192 kHz
Headphone Output	6.3 mm stereo jack, up to 300 mW
Line Output	RCA stereo, 2 Vrms
Input Interface	USB 2.0 (Type B)
Sample Rate	44.1, 48, 88.2, 96, 176.4, 192 kHz
Dynamic Range	120 dB (DAC)
Signal-to-Noise Ratio	117 dB
Chipset	ASUS AV100 high-definition audio processor
Features	Hi-Fi grade components, replaceable op-amps
Compatible Systems	Windows XP/Vista/7/8/10, Mac OS X
Cleaning & Maintenance	Wipe with dry cloth; avoid liquids
Safety	Operating temperature: 0-40°C; do not expose to moisture
Spare Parts & Repairability	Replaceable op-amp sockets; consult ASUS service centers
General Information	External USB sound card for high-fidelity audio

Frequently Asked Questions - Xonar Essence STU ASUS

How do I connect the Xonar Essence STU to my computer?

Connect the device using the included USB cable to a USB 2.0 port. The computer will automatically detect it. For optimal performance, install the latest driver from the ASUS website.

Does the Xonar Essence STU support headphone impedance up to 600 ohms?

Yes, the Xonar Essence STU is designed to drive high-impedance headphones up to 600 ohms, delivering clean and powerful audio.

Can I use the Xonar Essence STU as a standalone DAC?

Yes, it functions as an external DAC via USB input, outputting analog audio through the RCA line outputs. You can connect it to an amplifier or active speakers.

How do I change the operational amplifier (op-amp) on the Xonar Essence STU?

The device features socketed op-amps. Power down, open the casing, and gently remove the existing op-amp. Insert a compatible one, ensuring correct orientation. Refer to the manual for details.

Is the Xonar Essence STU compatible with macOS?

Yes, it works with macOS without additional drivers for basic playback. For advanced features, check ASUS support page for macOS drivers.

What is the maximum sample rate supported?

The device supports sample rates up to 24-bit/192 kHz via USB, providing high-resolution audio playback.

Does the Xonar Essence STU require an external power supply?

No, it is USB-powered. However, for optimal performance, connect it to a powered USB port or a USB hub with external power.

Can I use the line output and headphone output simultaneously?

Yes, both outputs can be used at the same time. The headphone output has its own volume control, while the line output is fixed or controlled via software.

How do I clean the Xonar Essence STU?

Use a soft, dry cloth to wipe the exterior. Do not use any liquids or solvents. Keep the device away from dust and moisture.

What should I do if the device is not recognized by my computer?

Try a different USB port, restart the computer, or reinstall the drivers. If the issue persists, check the cable or contact ASUS support.

USER MANUAL Xonar Essence STU ASUS

User manual

Copyright © 2015 ASUSTeK Computer Inc. All Rights Reserved.

No part of this manual, including the products and software described in it, may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form or by any means, except documentation kept by the purchaser for backup purposes, without the express written permission of ASUSTeK COMPUTER INC. ("ASUS").

Product warranty or service will not be extended if: (1) the product is repaired, modified or altered, unless such repair, modification of alteration is authorized in writing by ASUS; or (2) the serial number of the product is defaced or missing.

ASUS PROVIDES THIS MANUAL "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL ASUS, ITS DIRECTORS, OFFICERS, EMPLOYEES OR AGENTS BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF PROFITS, LOSS OF BUSINESS, LOSS OF USE OR DATA, INTERRUPTION OF BUSINESS AND THE LIKE), EVEN IF ASUS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES ARISING FROM ANY DEFECT OR ERROR IN THIS MANUAL OR PRODUCT.

SPECIFICATIONS AND INFORMATION CONTAINED IN THIS MANUAL ARE FURNISHED FOR INFORMATIONAL USE ONLY, AND ARE SUBJECT TO CHANGE AT ANY TIME WITHOUT NOTICE, AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY ASUS. ASUS ASSUMES NO RESPONSIBILITY OR LIABILITY FOR ANY ERRORS OR INACCURACIES THAT MAY APPEAR IN THIS MANUAL, INCLUDING THE PRODUCTS AND SOFTWARE DESCRIBED IN IT.

Products and corporate names appearing in this manual may or may not be registered trademarks or copyrights of their respective companies, and are used only for identification or explanation and to the owners' benefit, without intent to infringe.

Contents

Introduction......4

Package contents......4

Safety Information....5

Driver installation....6

Functionality 7

1. USB DAC (Digital-to-Analog Converter)....7
2. Stand alone DAC....8
3. Headphone amplifier....8

Front Panel....9

Rear Panel....10

Hardware Introduction ...... 12

Connections....13

Input 13

1. NB/PC-USB connections ....13
2. Digital audio input connections .....14

Output....15

1. With Amplifier and Passive Speaker System....15
2. With Active Speaker directly 16
3. With Headphone/Headset....16

Specifications 17

Introduction

The Xonar Essence STU USB DAC is ASUS Xonar's innovative response to the worldwide trend of PC Hi-Fi. With the number of PC audiophiles growing fast due to the convenience and high resolution of digitalized audio content, the Xonar Essence product line is committed to providing solutions for their needs to enjoy extreme high-fidelity music with any PC.

The Xonar Essence STU provides the best solution for any PC audiophile or aspiring audiophile to enjoy their music with extreme clarity, detail, and hassle-free controls, helping to rediscover one's music collection.

Package Contents

This package should contain the following:

• ASUS Xonar Essence STU Hi-Fi USB DAC x1 • USB cable (Type B-A) x1 • Power cord x1 (some versions may include 2 power cords for different countries) • Power adapter x1 • User manual x1 • Installation driver CD x1 • Product stand x1

Safety Information

For your own safety, please read the following important safety instructions carefully before attempting to connect this unit to the mains power supply. They will also help you get the best performance from the unit and prolong its life.

1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean the machine surface with a cloth (without any detergent).
7. Do not block any ventilation openings. Install in accordance with the manufacturer's instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding-type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.

1. Unplug this apparatus during lightning storms or when unused for long periods of time.
2. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as the power-supply adaptor having been damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.

Driver installation

After connecting ASUS Xonar Essence STU with your computer by the bundled USB cable, you need to install the device driver that enables the Xonar Essence STU to work with Windows operating system.

NOTES:

• The driver is only needed when you connect ASUS Xonar Essence STU with PC/NB.
• The version and content of the support CD are subject to change without notice.

To install the device driver:

1. Insert the ASUS Xonar Essence STU support CD into your optical drive. If Autorun is enabled, the ASUS Xonar Essence STU driver screen appears automatically. Go to step 4. If Autorun is not enabled in your computer, perform step 2.
2. Click My Computer on your desktop and double-click the optical drive icon.
3. Double-click the setup.exe icon located on the optical drive.
4. Follow the on-screen instructions to complete the installation. Read the END USER LICENSE AGREEMENT in the process and make sure that you understand and accept it before continuing the installation.
5. When the installation finishes, you may be prompted to restart your computer. You can choose to restart the computer later if desired.

System requirements

To ensure a successful installation of the ASUS Xonar Essence STU USB DAC, your computer must meet the following requirements:

- IBM compatible PC with one USB2.0 (or higher) compatible port for the USB audio device

- Microsoft Windows 10 / 8.1 / 8 (32/64bit) / Windows 7 (32/64bit) / Windows XP (32/64bit) / MCE2005

- Intel Pentium 4 1.4GHz or AMD Athlon 1400 CPU or faster CPU

- 256 MB DRAM system memory

- 60 MB available HDD space for driver installation package

- CD-ROM drive (or DVD-ROM drive) for software installation

- High-quality headphones or powered analog speakers to enjoy the ultra-high fidelity sound of the card

Functionality

1. USB DAC (Digital-to-Analog Converter)

Clear, detailed, life-like sound for your digital music collection in PC/NB, with all the connections (XLR, RCA) you need for end devices.

Steps:

• Connect PC/NB with a USB cable
• Need to install driver in your PC/NB to work
• Select "USB" in front panel as the input source

Desktop PC Notebook PC

2. Stand alone DAC

With S/PDIF in and input select, it also serves as an independent DAC which connects with digital inputs such as CD audio source and then plays to the end devices.

Steps:

• Connect with other audio resource with S/PDIF input (by Coaxial/Optical cable)
• Select COA (coaxial input) or TOS (optical input) in the front panel as the input source

3. Headphone amplifier

Grants 100% performance of ALL hi-end headphones, even with impedance up to 600ohms, providing extra dynamics and sound details.

Steps:

- Connect with high-quality headphones/headsets

Front Panel

1. Power On/Off

Press to turn on and again to turn off.

2. Input selection

Press to select audio input source: USB, Toslink, Coaxial, or AUX audio input.

3. Input selection/Bit perfect indicator

The corresponding LED will light up to show which audio source has been selected.

4. Speaker volume control

The volume control adjusts the output level of unbalanced RCA output.

5. Headphone volume control

The volume control adjusts the output levels of the headphone jack.

6. Headphone Gain indicator

The LED will light up based on the selected headphone gain setting.

7. Headphone output

Connect your high-quality headphones/headsets with 6.3 mm connector. Use a 6.3 mm/3.5 mm connector if your headphones/headsets have 3.5 mm ports.

Rear Panel

1. Headphone Gain Selection

Toggle the switch to change between low or high headphone gain settings.

NOTE: If you have a low impedance headset/headphone, please do not switch to high gain setting. When switching between high and low gain settings, please remove the headphone/headset connected before proceeding.

2. Unbalanced RCA Output (line-out)

Conventional stereo outputs for connection to the line-level phono/RCA inputs of a speaker.

3. Aux In

Connect iDevices such as iPhone, iPod, or iPad into this port.

4. Coaxial S/PDIF Input

Connect your digital source, such as CD/DVD players or computer with S/PDIF output, to digital input. Use either S/PDIF coaxial or Toslink optical type, each being of equal quality.

5. Toslink Optical Input

This port is for Toslink Optical Input.

NOTE: This unit only accepts two-channel LPCM digital audio (e.g. Dolby Digital 2.0). You cannot connect a Dolby Digital 5.1 or a DTS signal as they will not be recognized. If you wish to connect a DVD or similar device, please ensure that the sound output of your player is set to two-channel PCM.

6. USB port

Connect a PC via a Type B to Type A USB lead.

NOTE: You need to install the device driver that enables the Xonar Essence STU to work with Windows operating system.

7. Power port (AC in)

Plug the supplied power adapter into the Xonar Essence STU once you have completed all connections.

Hardware Introduction

1. USB Audio processor: C-Media CMI6631A (for USB input)
2. S/PDIF receiver: TI PCM9211 (for digital input)
3. DAC: TI PCM1792A
4. Swappable Op-amps: LME49720 x2
5. Swappable Op-amps: LM4562 x1
6. Swappable Op-amps: OPA2132 x1
7. Film Cap (red ones): WIMA FKP2
8. Op-amps: LM4562 (for Speaker out)
9. Headphone Amplifier: TPA6120A2 (for Headphone out)

Connections

Input

1. NB/PC-USB connections

NOTE: Do not turn on the machine until all connections have been made.

(1) Connect a USB 'B-A' type lead (as illustrated at left) from the Xonar Essence STU's USB input to one of the USB ports on the PC/NB. (2) Turn on the Xonar Essence STU using the front panel On/Off switch and make sure that the USB input is selected (USB LED lit). (3) Install the device driver that enables the Xonar Essence STU to work with Windows operating system.

NOTES:

- The PC's previous audio output device should now be temporarily disabled and the Xonar Essence STU becomes the default audio playback device for the PC/NB. This can be confirmed in the Control Panel's Sounds, Speech and Audio Devices properties window under the Volume tab.

- If you wish to disconnect your Xonar Essence STU and return to using your previous soundcard, etc., simply disconnect it or switch off the power on the front panel. If the PC fails to disable the Xonar Essence STU and automatically re-enable your default soundcard, you can manually disable the Xonar Essence STU in the hardware device manager. To do this, navigate to the Device Manager (click Start — Control Panel — (Vista: Performance and Maintenance —) System — Hardware— Device Manager in Windows XP). Scroll down the device manager window and expand the heading Sound, Video and Game Controllers to display a list of the connected devices. Click on this description to highlight in blue and then click on the Disable icon at the top of the window. A warning message will appear: “Disabling this device will cause it to stop functioning. Do you really want to disable it?” Click Yes to disable the Xonar Essence STU. The previous audio playback device will now be re-instated by Windows.

2. Digital audio input connections

(1) Connect your digital source (ex. CD/DVD players or some PC/NB with SPDIF output) to Digital Input. Either S/P DIF Coaxial or Toslink optical types can be used, each being of equal quality.

NOTE: Both Coaxial and Toslink Inputs can be used to connect and run equipment at the same time.

Output

1. With Amplifier and Passive Speaker System

Amplifier

(1) Connect the unbalanced input of an amplifier to the unbalanced (RCA/Phono) output of the Xonar Essence STU. (2) Connect the amplifier to a Passive Speaker System.

2. With Active Speaker directly

(1) Connect Xonar Essence STU with a set of active speakers directly.

3. With Headphone/Headset

Headphones/headsets

(1) Connect Xonar Essence STU with high-quality headphones/headsets directly.

Specifications

Items Description
Audio Performance
Output Signal-to-Noise Ratio(A-Weighted):	Line Out: 120dBHeadphone: 117dB
Output Total Harmonic Distortion + Noise at 1kHz@-3dB (A-Weighted):	Line Out: -108dBHeadphone: -101dB
Output Full-Scale Voltage	Line Out: 2VrmsHeadphone: 7Vrms
Frequency Response (-3dB, 24-bit/192kHz output):	<10Hz to 48kHz
Bus Compatibility
USB USB 2.0 High speed
S/PDIF IEC 61937
Main Chipset
Audio Processor C-Media CM6631A
S/PDFI Receiver PCM9211
D-A Converter for Analog Inputs TI PCM1792A
OP Amp
Balanced / Un-balanced I/V LME49720
Balanced / Un-balanced LFP LM4562
Headphone TPA6120A2
Output impedance
Line out 100 ohm
Headphone out 10 ohm
Clock
Crystal clock 12MHz
Oscillator 45.1584MHz (for 44.1KHz sample rate)

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Specifications

Sample Rate and Resolution
Analog Playback Sample Rate and Resolution	44.1K/48K/88.2K/96K/176.4K/192KHz @ 16/24bit
Power consumption (Max) 12W I/O Ports
Output Jack:	Line Out (Dual RCA)
	6.3mm Jack headphone output
	Metal with plated gold, black housing
Input Jack:	USB jack
	Coaxial / Toslink jack
	AUX in phone jack
	Metal with plated gold, black housing
Power Input Jack: DC in 12V
Volume controller	Balanced Output: Taper A Potentiometer
	Headphone Output: Taper A Potentiometer
Power input range AC 90~264V
LED Indicator
One color LED ∅3mm Lamp LED White color
Button
Push Button 2-pin Tact switch
Accessories
Accessories	Power cord x1
	Power adaptor x1
	USB cable x1
	Product Stand x1
	6.3mm to 3.5mm adaptor x1
	User manual x1
	Installation driver CD x1

* Specifications are subject to change without notice.