Circuit Slices Preamp+ User manual

Circuit Slices, LLC
Preamp+
CS044
CS044-UM v2.0| www.circuitslices.com
1
The Circuit Slices Preamp+ (model number CS044) is a dual-function module for Eurorack-compatible
synthesizers. In this narrow module is a microphone preamp and an envelope follower with CV and gate
outputs. Use this module to process acoustic sources or to control functions in a modular synthesizer
using acoustic sound.
Features and Specifications for the CS044 Preamp+
All analog design using state of the art ICs and surface-mount construction
Microphone amplifier has a voltage gain of over 100 (+40dB)
Designed to use inexpensive Electret microphones
The Preamp output is “normal” patched to the envelope follower’s input
The preamp and follower can be used separately –patching to the follower IN disconnects the preamp
Gain control uses a panel-mounted 9mm potentiometer with a heavy-duty knob
Jumper selectable pull-up resistor to power Electret microphones
Dual-color LED indicates output signal level: above 2V peak (green) and above 5V peak (orange to red)
Green LED above the GATE jack indicates when the GATE output is high (5V)
Envelope follower tracks the input’s peak level from 0V to 5V and up to 10V
Envelope follower outputs a GATE signal (5V) used to trigger envelope generators or other devices
Gate threshold approximately 1.5V at follower’s input
Includes power cable and case screws
Reverse power protection
Power: +12 VDC @ 40 mA, -12 DC @ 9 mA, using a standard Eurorack 10-pin power connection
Connections: Standard 3.5mm jacks
Depth: 30 mm
Panel width: 4 HP

Circuit Slices, LLC
Preamp+
CS044
CS044-UM v2.0| www.circuitslices.com
2
Installation
Simply route the ribbon-cable power connector to your power bus and mount the panel using the
supplied screws. The red stripe on the ribbon cable must be toward the -12V pin on the power bus and
the module. We supply a cable without a strain-relief on the 10-pin connector, to keep the module’s
overall width narrow.
Using the Preamp and Envelope Follower
The preamp is designed for use with an electret microphone; however, you may try using an electric
guitar pickup or other low-level / high-impedance transducers as an input. Shorting jumper header, J11
on the PCB selects an electret microphone (marked “e-mic”) or non-electret device (marked “d-mic”).
The jumper is factory-set for use with electret microphones.
Now give it try. Starting with the gain control turned fully counterclockwise, plug a microphone into the
preamp IN jack. While speaking into the mic, turn the preamp knob clockwise until the top, dual-color
LED starts to light green, indicating a good signal level. Orange to bright red means you might be
clipping the signal. Note that a loud sound will clip, even if the gain control is at a low setting. You
should also see the green GATE LED turn on and then turn off when you stop speaking. Now, patch the
preamp output to a synth module that is ultimately patched to your external audio system, to hear your
amplified voice.
IN
OUT
IN
OUT
GATE
PREAMP+
Amplified signal to VCA, VCF, Ring Mod, etc.
Envelope output to VCA, VCF, etc.
Gate output to ADSR, sequencer, etc.
Gain control
LED output level indicator
Off = low signal
Green = good signal
Orange/red = high level signal
Microphone input
0V to 5V gate, when Follower input above +1.5V
OV to Peak value of signal output
+/- 5V signal with headroom
External input to Follower
Disconnects preamp

Circuit Slices, LLC
Preamp+
CS044
CS044-UM v2.0| www.circuitslices.com
3
--- The intended use for this module is not as a substitution for a lead vocal sound system, but rather to
use acoustic sources for control and as signal sources in a modular synthesizer rig. ---
With external acoustic-produced signals in the analog synthesizer world, you can modify the signal or
use the signal to control other functions in your synthesizer.
The envelope follower output produces a positive DC control voltage that tracks the peak level of the
follower input. This DC envelope can be patched to module CV inputs. This means you can use the
amplitude of your voice, or other acoustic source, to control functions in a synthesizer patch. Use your
voice to control a VCF and simultaneously, use the GATE signal to trigger an envelope generator. If you
have a ring modulator, such as the Circuit Slices CS045, you can patch the preamp to the modulator to
produce the classic, if not trite, robot-voice effect used in very old science fiction movies. Or try using
the beat from an acoustic drum to step a sequencer or trigger an envelope generator.
The patch examples described are simple preamp configurations and only scratch the surface of the
ways you might use this device. This module opens up the capabilities of any modular synthesizer
system.
This module is limited-warranted for one year with parts, under normal use –not including the
application of reverse or over-voltage power by customer. Return shipping to Circuit Slices from
customer not included. Return to Circuit Slices, LLC for repairs. Circuit Slices, LLC reserves the right to
replace the module if necessary. Please keep your receipt / packing slip for warranty information.
Circuit Slices, LLC
10028 Windjammer Trail
Aurora, OH 44202