www.switchtrix.co.uk

Here are custom made(not by EMS)  VCS3/Synthi A Board A,B and C.

Ideal replacement/upgrade for VCS3/SYNTHI or custom build for clone,modular etc
Fully populated,calibrated and tested.Professionlly made 1.6mm FR4 HASL lead PCB.Sound and function identical to the originals.See last pic for a waveform comparison between an original VCS3 and these pcb's

BOARD C


Built with BC169/184 and BC258B/212 transistors as per the original.BCM847DS used for expo convertor with 1K tempco resistor.
Molex KK connector for added functions.Oscillator High/Low,Oscillator sync in,CV input for direct -0.32 V/oct and shape cv.
Oscillator x3
Noise Generator
Meter amplifier

BOARD B


Built with BC169/184 and BC258B/212 transistors and discreet TAB101 as per the original
Molex KK connector for added functions Fiter slew,Pre/post 1974 filter response and slow/medium/fast Envelope shaper times.

Features the following modules

Inverting amplifiers x2
Ring Modulator(TAB101)
Envelope shaper(Trapezoid/VCA)
Voltage controlled Filter(Diode Ladder)


BOARD A


Built with BC169/184 and BC258B/212 transistors as per the original.Upgraded power supply..

Features the following modules

REGULATOR CIRCUIT NOW USING LM317/337 PROVIDING UP TO 1.5 AMPS.PERFECT FOR MARK 1 MACHINES SO THEY CAN USE THE KS SEQUENCER

OUTPUT AMPLIFIERS(MATCHED FETS FOR CHANNEL BALANCE)

REVERB DRIVER

Power supply +12v/-9V DC

Wiring diagrams included

Here are some sound samples.

https://www.dropbox.com/sh/rv9px4u2778sizi/AAAApmtJ2iM013pdKRdrmxOia?dl=0

Any questions please ask
Thanks for looking