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BLACET RESEARCH MODEL SB2780 Splitter
BLACET RESEARCH MODEL SB2790 Mixer
User Manual
Blacet Research 15210 Orchard Rd Guerneville CA 95446
info@blacet.com http://www.blacet.com 707-869-9164
Contents Copyright.
Reproduction by any means including the Internet prohibited without permission.
This document contains proprietary and trade secret information of Blacet Research and is provided
as a service to the module owner. Any unauthorized duplication or transferral may violate trade secret laws.
Contents subject to change without notice.
Buffered Splitter/Mixer
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Introduction
The Blacet SB2780 Splitter and SB2790 Mixer are fully buffered precision modules designed for processing control
voltages and audio signals.
The Splitter is a “One to Three” module, taking one input and splitting it into three outputs. Channel A features an
attenuator. Channel B has a phase reversing attenuator, which will change the polarity of a CV or the phase of an
audio signal. Channel C is “straight thru” with no controls.
The Mixer is a “Three to One” module, mixing up to three input signals and providing one output. Channel A
features an attenuator. Channel B has a phase reversing attenuator, which will change the polarity of a CV or the
phase of an audio signal. Channel C is “straight thru” with no controls, although a trimmer on the PCB allows
setting the level from 50% to 100%. The factory setting is midpoint ( 75%.).
Channel A
Attenuator
Channel A
Output
Channel B
Output
Channel C
Output
Channel B
Attenuator &
Phase Control
Input
Operation Tips
A Splitter is similar to a “Multi” but with
more control options.
For example, if you have only one EG1
(ADSR), you can split the EG output to
drive both a filter and a VCA. Use the “C”
out to control the VCA.
Use the “B”out for the filter frequency as
this allows you to fine tune the sound as
well as reversing the sweep with the “B”
pot phase control.
You can also use the “A” out to control the
VCO octave, filter Q, etc.
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Channel A
Attenuator
Channel A
Input
Channel B
Input
Channel C
Input
Channel B
Attenuator &
Phase Control
Mixer Output
Operation Tips
Use this mixer to spot mix CVs and audio
in your patches.
It may be helpful to assign the softest sound
or smallest CV to the “C” input as the other
larger inputs can be attenuated by the pots.
Note that the “C” level can also be
adjusted from 50 to 100% by the on board
trimmer if “full on” is not the best setting
for your typical use.
One typical application is to mix several
CV sources and apply them to a VCO or
filter frequency input.
For example, a mixture of noise and LFO
triangle sent to the VCO octave input can
be adjusted for an octave jump with some
uncertainty.
Power Input Connector JPWR: This PCB connector requires a source of regulated +15Vdc and -15Vdc power to
run the module. Use a Blacet PS500 supply or the equivalent.
Connections to this connector should be made only when the power supply is OFF and the connector must be
positioned correctly on the pins. As using the wrong supply can cause damage to the unit, please contact us if you
have any questions! Do not attempt to use “wall warts” to power the module.
Calibration: Both PCBs have a “Null” trimmer for the “B” Channel (RT1). Adjust this with the B channel front
panel control at center detent position for minimum output, using an audio signal input (“IN” Splitter or “IN B
Mixer).
The Mixer also has a “C Level” trimmer (RT2) which can be adjusted from 50% to 100%. The center position is 75%.
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Specifications
Front Panel Size: 5.25” H x 1.5" W
Module Depth (Splitter): 2.3”
Module Depth (Mixer): 2.7”
Input/Output Jacks: 3.5 mm (1/8”)
Input/Output Range: +/-13.5V
Power (Splitter): +/-15 Vdc @+9/-9mA
Power (Mixer): +/-15 Vdc @+13/-13mA
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