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All circuits are for personal use only
© Marjan Systems/Marjan Urekar 1999.-2001. All rights reserved.
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Familiar SEM style State Variable Filter LP/BP/HP
with discrete components instead OTAs.
Triple Waveshaper Module
Triple WS and one part of Serge Waveform
use this scheme, just one opamp from LM3900,
it takes saw VCO input and rectify it to triangle/sine
output, but can also be timbre modulator for any signal.
#194 Fixed Bandpass Filter Not
very exotic module, but it might come handy.
Splits input signal into four bands 200/200-900/
900-4000/4000 Hz, using just few transistors.
Polysix Ensemble LFO
Dual fixed three phase LFO used for modulating triple
BBD delay lines in Ensemble effects. Uses single CD4069
and has CV control of Intensity (amplitude).
Simple discrete VCA with 9 transistors. Crucial part
Mini's sound, together with it's VCOs, VCF and fast EGs.
#291 Dual Bandpass VCF
VCBPF with Vactrols and lots of control/process power.
VC center freq (30Hz-15kHz) with offset, VC bandwidth
(1 semitone-4 octaves) with offset, resonance, FM,
input level, could be trimmed for selfosc.
Low noise and high dynamic range.
Sequential Pulse Source
10-step gate/trigger sequencer with CD4017. (updated)
Matrix-6 White Noise
Simple but nice sounding noise generator from polysynth.
IR Light Controller with CV (thanks to D.F.)
Superb LFO with waveshape and range controls.
UpSaw/Triangle/DownSaw and Pulse waveforms. (updated)
Standard CA3080 based design. (updated)
SH-09 Noise and S/H
My favourite! Simple transistor white/pink noise generator
and S/H with two FETs. Add it to your boring LFO section!
VCS3 Type Ring Modulator
Neat RM based on famous VCS Synthi. Very low parts count,
but distinctive sound. Looks like discrete MC1496 chip!
Source VC LFO
Modification of standard tri/square LFO, with additional VCA.
VC and manual controls of speed and level parameters.
OTA design, based on VCA, reliable stuff. (updated)
Scans of (in)famous EML 101 schematics. Expo convertors, Oscillators
1,2 & 3 and VCF are here. Interesting "lo-end" approach.
Contact me if you have the rest of the schematics for this beast.
Based on Roland JX-3P and Korg MS10/20/Polysix VCAs.
Transistor and opamp, simple, noisy, strange, but works after all!
Marjan Systems and ForceMajeure
by Marjan Urekar