USB MATCHBOX
USB<>XLR ULTRA-DEFINITION CODEC
DESCRIPTION
The USB Matchbox is a high-performance professional audio codec. Used in place of a computer “sound card”, it
provides audiophile-quality performance, XLR analog stereo inputs and outputs at professional studio levels, and
the convenience of USB interface to any PC. The USB Matchbox is compatible with virtually any audio
recording/editing software. No special software or driver is needed. A USB 1.1 (or higher) connection to the PC is
required. The USB Matchbox is USB powered, and complies with the AES-48-2005 grounding standard.
INSTALLATION
ANALOG LINE INPUTS/OUTPUTS:
Connect balanced analog inputs and output to the XLR connectors as follows:
Pin 1 = GND, Pin 2 = HI, Pin 3 = LOW.
NOTE:
Ground loops cause hum, buzz, and other noises that are created by the computer mouse, drives, fan, and
keyboard.
Prevent noise by connecting ground wires at one end only.
The unbalanced AUX IN jacks can also be used; connect them as usual. (White = LEFT; Red = RIGHT.)
NOTE: See important notes on reverse side regarding use of the unbalanced AUX IN jacks.
The SPEAKER outputs can be used to feed an amplified speaker system or “computer speakers”. Use a 3.5mm
TRS plug wired as follows: Tip = LEFT, Ring = RIGHT, Sleeve = GND. The Speaker output level is fixed. The
Speaker audio can be muted via a contact closure at the MUTE jack. Use a 3.5mm TRS plug. Connect an
external contact closure between the Tip and Sleeve.
COMPUTER CONNECTION:
First, close any audio-related programs. Use a USB cable to connect the USB
Matchbox to any USB port on the PC.
Warning! Do NOT use a “USB HUB”! Connect the cable from the USB
Matchbox
directly
to the USB port on the computer.
The computer should recognize the USB Matchbox as
“
USB Audio Codec”.
No additional software or drivers are needed. When audio software is started, it may be
necessary to change its Settings to select the
USB Audio Codec
as its default.
WINDOWS* VOLUME SETTING
BEFORE USING USB MATCHBOX, be sure to check the Windows “SPEAKER VOLUME” setting. The Speaker
Volume can be accessed via the Windows Control Panel under “Sound and audio devices” or “Adjust the system
volume”. Select “Volume” or “Set system volume”, then adjust the slider.
In most cases, the Speaker Volume
should be set to MAXIMUM.
*Windows is a registered trademark of Microsoft Corporation.
OUTPUT LEVEL CALIBRATION
The USB Matchbox is calibrated to operate with balanced I/O levels of +4 dBu. Output levels can be changed via
the recessed OUTPUT trimmers; use a small screwdriver to carefully adjust. NOTE: There is 15 dB of digital
headroom above +4 dBu: a calibration tone recorded at 0 dBfs will produce an output level of about +19 dBu.
OPERATION
Feed program audio into the unit, and set the RECord LEVel control as indicated by the software being used for
recording. The BAL trimmer can be used to fine-tune left/right channel balance. Use a small screwdriver to
carefully adjust.
To play a recording, simply play the file. Audio will be present on the XLR output jacks.
SPECIFICATIONS
Balanced analog inputs/outputs
Stereo, nom. +4 dBu @ -15 dBfs, 20K input imp; CMRR = 90 db @60 Hz; O24 dBu, 600 ohms
Unbalanced analog input
Stereo, -10 dBv, 10K input impedance
Speaker output
Stereo, compatible with computer speaker systems
Mute control
Contact closure will mute Speaker output
Phones output
For headphones, 24 ohms or higher. (Do not use older “8-ohm” headphones.)
Sample rates supported
48, 44.1, or 32 kHz, software defined
Resolution, dynamic range
16 bit stereo or mono, software defined
USB supported
USB 1.1 or higher, USB powered
HENRY ENGINEERING
503 Key Vista Drive
Sierra Madre, CA 91024
Tel: 626.355.3656
Fax: 626.355.0077
www.henryeng.com
TM
