MICROMIXER
FOUR INPUT STEREO MIXER
HENRY ENGINEERING
503 Key Vista Drive
Sierra Madre, CA 91024
tel: 626.355.3656
fax: 626.355.0077
website: www.henryeng.com
DESCRIPTION
MICROMIXER is a four-input, two-output stereo mixer/combiner for utility use. The unit has
balanced bridging inputs for four audio sources (two stereo pairs) which can be mixed to two
outputs (one stereo pair). A level control is provided for each input. Selectable 'assign'
switching permits any input to be fed to either or both outputs. DC coupled circuitry provides
excellent sonic performance.
INSTALLATION
All connections to the MicroMixer are made via plug-in connectors. Remove about 1/8” of
insulaton, insert wires into the plug, and tighten the screws. Be sure that no bare wires are
exposed.
Audio inputs to the MicroMixer should be connected to the balanced input terminals labeled 1, 2,
3, and 4. For unbalanced inputs, install a jumper between the (-) terminal and G (ground). All
inputs are bridging; it is not necessary to terminate the source unless required by the source
equipment.
Audio outputs from the MicroMixer are connected to the two outputs labeled L (Left) and
R (Right). The output circuitry will drive any load of 600 ohms or higher. It is not necessary to
terminate the outputs. For unbalanced outputs, connect to the (+) and G terminals only. DO
NOT short the (-) terminal to ground.
OPERATION
The input levels to the MicroMixer should be between -10 and +8 dBm. Adjust each input
channel using the INPUT LEVEL controls. Unity gain is achieved with these controls set to 10
o'clock; with nominal input levels of +4 dBm the Input Level controls should be run near this
setting. It is recommended that input levels be initially set with a level indicator (VU meter,
scope, VOM) temporarily connected to the MicroMixer's output to monitor output levels. The
average output level should not exceed +8 dBm to ensure adequate headroom.
Each output channel (L & R) has four ASSIGN switches that determine which of the four input
signals are fed to that output. Select the input sources desired by switching the appropriate
channels ON (down). For example, if inputs 1 and 3 should be fed to the LEFT output, set Left
output assign switches 1 and 3 ON, with 2 and 4 OFF.
SPECIFICATIONS
INPUTS -10 to +8 dBm; balanced 20K or unbalanced 10K
GAIN 10 dB maximum
OUTPUTS +4 dBm nominal, +26 dBm max; 600 ohms or higher, 4X
FREQ RESP DC to 20 kHz, +/- 0.25 Db
NOISE 80 dB below +4 dBm output
DISTORTION .008% IM/THD
