MD1 Pro - Audio Equipment SAMSON - Free user manual and instructions

Type	Passive mono direct box
Frequency response	18 Hz to 40 kHz ±0.1 dB
Maximum input	+20 dB (0.35% THD)
Dynamic range	Greater than 100 dB (balanced output)
Noise floor	-117 dB
Total harmonic distortion	Less than 0.03% from 20 Hz to 40 kHz
Input impedance	400 kΩ
Output impedance	250 Ω ±20%
Transformer	Faraday shielded, ratio 15:1
Attenuator switch (PAD)	0 dB, -15 dB, -30 dB
Ground Lift	Disconnects XLR pin 1 (output)
Input connectors	6.35 mm unbalanced jack (In and Thru)
Output connector	Balanced male XLR
Construction	14-gauge steel chassis
Dimensions	127 x 86 x 49.6 mm (5 x 3.38 x 1.95 in)
Weight	667 g (1.47 lb)
Power	Passive, no power required
Maintenance	Clean with a dry, soft cloth

Frequently Asked Questions - MD1 Pro SAMSON

How to connect a guitar to the MD1 Pro?

Plug your guitar (or other instrument) into the 6.35 mm INPUT jack. The BALANCED OUTPUT XLR connects to a microphone input on the mixing console. Use the THRU output to send the signal to an amp or monitor if necessary.

What is the attenuator switch (PAD) used for?

The PAD switch attenuates the input signal by -15 dB or -30 dB to prevent distortion when connecting high line-level or speaker-level sources. Always start with the -30 dB position with power amplifier outputs.

When to use the ground lift?

Set the GROUND LIFT switch to the LIFT position if you hear a hum or buzz (ground loop). This disconnects the ground from the input shield to eliminate interference.

Can I connect a guitar amplifier output to the MD1 Pro?

Yes, but set the PAD switch to -30 dB before connecting. The MD1 Pro can accept up to 40 V. The table in the manual indicates maximum power according to impedance (e.g., 400 W into 4 Ω).

What is the difference between the THRU and BALANCED OUTPUT?

The THRU output is a direct copy of the input signal (unbalanced) that can be sent to an amp or stage monitor. The BALANCED OUTPUT is a low-impedance balanced signal for long distances without noise, typically to the console.

Does the MD1 Pro require power?

No, the MD1 Pro is completely passive: it requires no batteries or phantom power. The transformer provides balancing without an external power source.

How to use the MD1 Pro with a keyboard or drum machine?

Connect your keyboard output to the INPUT jack. If the signal is too loud (distortion), use the PAD at -15 dB. Connect the XLR output to the console. You can also use the THRU output for a monitoring amp.

What to do if the signal is too weak after the MD1 Pro?

Check that the PAD switch is set to 0 dB (no attenuation). The MD1 Pro does not amplify; it adapts impedance. Make sure the console receives the signal and increase input gain if necessary.

Does the MD1 Pro work with long XLR cables?

Yes, the low-impedance balanced output allows for long distances (over 30 m) without signal loss or excessive noise, thanks to common-mode rejection.

How to maintain the MD1 Pro?

Clean the chassis with a dry, soft cloth. Avoid solvents. Store in a dry place. No user-serviceable internal parts; contact Samson for repairs.

USER MANUAL MD1 Pro SAMSON

MD1 Pro Mono Passive Direct Box

SAMSON MD1 PRO Mono Direct Passive Box

Quick Start Guide

SAMSON®

If you want to dispose this product, do not mix it with general household waste. There is a separate collection system for used electronic products in accordance with legislation that requires proper treatment, recovery and recycling.

Private household in the 28 member states of the EU, in Switzerland and Norway may return their used electronic products free of charge to designated collection facilities or to a retailer (if you purchase a similar new one).

For Countries not mentioned above, please contact your local authorities for a correct method of disposal. By doing so you will ensure that your disposed product undergoes the necessary treatment, recovery and recycling and thus prevent potential negative effects on the environment and human health.

Copyright 2016, Samson Technologies Corp.

v3

Samson Technologies Corp.

45 Gilpin Avenue

Hauppauge, New York 11788-8816

Phone: 1-800-3-SAMSON (1-800-372-6766)

Fax: [phone]

www.samsontech.com

Introduction

A direct insertion box, or DI box, converts unbalanced high impedance signals to balanced low impedance signals. This provides the facility to run long cables without deterioration of the signal, as well as connecting audio signals to a mixer's microphone input.

Samson's S-Max Direct Boxes combines premium sound circuitry with durable, roadworthy construction to provide high-quality signal connection solutions for live and studio applications. The Samson MD1 Pro Professional Mono Passive Direct Box offers a variety of DI solutions for live sound and recording applications. You can connect all kinds of audio signals like those from keyboards, drum machines, mixers, guitars, outboard signal processors and even from the powered speaker output from an amplifier.

Samson's STLX Faraday shielded transformer delivers an extended, flat frequency response, ultra-low distortion, and eliminates hum and RF interference. The MD1 Pro balanced output provide a clean signal, that is less susceptible to noise when compared to an unbalanced cable, which allows for running longer lengths of cables. Another benefit from a balanced connection is CMR (Common Mode Rejection), which provides cancellation of interference (hums and buzzes), while leaving the original signal pure.

The THRU jack enables you to tap off the signal from the input and pass the signal to an amplifier or monitor without affecting the original sound. This can eliminate the need for miking the guitar amplifier, which in many cases is preferable, especially as more bands are using in-ear monitors.

With proper care and maintenance, your MD1 Pro will operate trouble-free for many years. Should your direct box ever require servicing, a Return Authorization (RA) number must be obtained before shipping your unit to Samson. Without this number, the unit will not be accepted. Please call Samson at 1-800-3SAMSON (1-800-372-6766) for an RA number prior to shipping your unit. If your direct box was purchased outside of the United States, contact your local distributor for warranty details and service information.

Callouts

12 INPUT THRU -5dB -30dB 4 GROUND BALANCED OUTPUT LIFT 5

1. INPUT - 1/4" hi-Z input jack for connecting for instrument, line level, or speaker level audio signals.
2. THRU - 1/4" output for passing the input signal through to a stage amplifier or monitor system.
3. -15dB / -30dB Pad switch – When engaged, the input level is attenuated by either -15dB or -30dB to prevent distortion or when connecting to a speaker level output.
4. GROUND LIFT – When the switch is engaged, the input ground (shield) is disconnected.
5. BALANCED OUTPUT – Male XLR low-Z connector.

Setup

The MD1 Pro can be quite useful on stage or in the studio for connecting unbalanced audio sources or instruments with pickups. By utilizing the MD1 Pro, the signal can be sent cleanly for long distances while benefiting from the low noise and common mode rejection provided by the balanced low-level output. The diagram following shows a typical hook-up for an acoustic guitar connected to an acoustic guitar amplifier and a PA system.

graph TD
    A["Music Player"] -->|Signal| B["MP3 Interface"]
    B --> C["Speaker 1"]
    B --> D["Speaker 2"]
    B --> E["Speaker 3"]
    C --> F["Output"]
    D --> F
    E --> F
    F --> G["Audio Display"]
    style A fill:#f9f,stroke:#333
    style B fill:#ccf,stroke:#333
    style C fill:#cfc,stroke:#333
    style D fill:#fcc,stroke:#333
    style E fill:#cff,stroke:#333

• Set the volume controls of your audio system to the off position.
• Connect your instrument or other audio source to the MD1 Pro INPUT jack.
• Connect the THRU output to a monitor speaker or sub-mixer.
• Connect the BALANCED OUTPUT to the microphone input of a mixer or other audio device.
• Raise the level of the audio system to the appropriate level.
• If you hear a hum or buzz set the GROUND LIFT switch to the LIFT position.
• If you hear distortion, set the pad switch to either the -15dB or -30dB position. You may need to adjust the input level of the mixer to make up for the attenuated signal.

Connecting Speaker Level Signals

The MD1 Pro provides the capability of tapping off the signals from amplifiers, such as the output of a guitar amp or any power amplifier. You can even use MD1 Pro to connect to the speaker output of a consumer stereo system to a mixer or PA system.

WARNING: Be sure that the pad switch is set to the -30dB position before connecting the signal from the output of any amplifier.

The following diagram shows how to connect the powered output of a guitar amplifier to a mixer.

graph TD
    A["Guitar Amplifier"] -->|Signal Flow| B["Front Panel"]
    B -->|Link Outputs| C["Rear Panel"]
    C -->|Balanced Output| D["Mixer"]
    D -->|Signal Flow| E["Speaker Cabinet"]
    E -->|Signal Flow| A
    style A fill:#f9f,stroke:#333
    style B fill:#ccf,stroke:#333
    style C fill:#ccf,stroke:#333
    style D fill:#cfc,stroke:#333
    style E fill:#fcc,stroke:#333

The MD1 Pro can accept signals up to 40 volts when the pad switch is in the -30dB position. Please use the following chart to calculate the maximum power output based on output impedance that will safely work with the MD1 Pro:

Power Impedance
800 Watts 2Ω
400 Watts 4Ω
200 Watts 8Ω
100 Watts 16Ω

Specifications

Type Mono Passive Direct Box

Frequency Response 18Hz to 40kHz ±0.1dB

Maximum Input +20dBu 0.35% THD

Dynamic Range >100dB @ Balanced Output

Noise Floor -117dB

Total harmonic distortion <0.03% from 20Hz to 40kHz

Input impedance 400kΩ

Output Impedance 250Ω ±20%

Transformer Faraday Shielded Transformer

Transformer Ratio 15:1

Input PAD Switch 0dB, -15dB, -30dB

Ground Lift Disconnects XLR pin-1 (Output)

Connectors 1/4" Phone Jack, unbalanced (In & Thru)

XLR, balanced (Output)

Construction 14 gauge steel chassis

Dimensions 5" x 3.38" x 1.95"

127mm x 86mm x 49.6mm

Weight 1.47lb

667g

ENFR ESIT

Block Diagram

graph LR
    A["Input"] --> B["Thru"]
    B --> C["Pad"]
    C --> D["0dB"]
    C --> E["-15dB"]
    C --> F["-30dB"]
    D --> G["Transformer"]
    E --> G
    F --> G
    G --> H["Balanced Output"]
    H --> I["Ground Lift"]

Samson Technologies Corp.

45 Gilpin Avenue

Hauppauge, New York 11788-8816

Phone: 1-800-3-SAMSON (1-800-372-6766)

Fax: [phone]

www.samsontech.com