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ASM-2 V1
Analogue Synthesiser

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The ASM-2 expands upon the popular ASM-1 with a number of new features and enhancements as detailed below.

The ASM-2 brings the process of building a complete analog synthesiser closer to fruition.


Items in red are enhancements over the ASM-1
A number of these refinements are courtesy of Magnus Danielson

Power requirements

-18 Volts @ 220mA
+18 Volts @ 240mA

VCO (x2)
inputs 6 x Exponential FM
2 x linear FM. +/-25% modulation from -15V to +15V
2 x pulse width. 0-100% from -5V to +5V
1 x sync with adjustable trigger level
outputs 1 x sawtooth
1 x rectangular
1 x triangle
1 x sine

uses a +/-10V reference for higher stability
improved sync circuitry



inputs 4 x cutoff CV+
1 x cutoff CV-
4 x signal in
outputs 1 x low-pass
1 x band-pass
1 x high-pass
1 x notch
extras Includes series resistors on all outputs


transistor ladder

inputs 3 x signal in
3x cutoffl CV
outputs 1 x output
VCA (x2)
inputs 2 x +signal in
1 x -signal in
3 x amplitude control CV
outputs 1 x output
extras Includes option for de-oscillation capacitor
ADSR (x2)

1 x GATE
1 x Re-Trigger

outputs 1 x ADSR out
extras Includes GATE input diode protection and ATTACK current limit protection
VCLFO (x2)
outputs 1 x triangle out
1 x square out

Includes voltage control of frequency
LED status indication of frequency

outputs 1 x white noise out
1 x coloured noise out
1 x random voltage out
extras Includes red/blue control of coloured noise
inputs 1 x CV in
outputs 1 x CV out
extras Includes on-board/off-board jumper option for linear and exponential glide slopes
Sample & Hold

1 x CV in
1 x signal in


1 x CV out
1 x GATE out (optional)
1 x TRIGGER out (optional)

1 x Uncommited Inverter

Power Supply
  • Onboard fixed-regulator power supply providing up to 500mA per rail (capable of larger currents up to 1A but will require additional off-board heatsinking).
  • Includes 3 buss-connectors for powering additional circuit
Ring Modulator

1 x X input
1 x Y input

outputs Sum and Difference of X and Y
Main PCB
  • All of the connections for inputs, outputs and panel components are bought out to the edge of the board on a 0.1" pitch allowing for several termination options including:- hard-wiring, terminal-pin termination, crimped termination and screw-terminal connection.
  • All panel pot connections are bought out to 3-way connectors allowing the user to either wire common pot pins on the panel or wire all pot pins back to the pcb
  • All trimpots are bought out to the edge of the pcb

ASM2-Guide Constructing the ASM-2 PCB CorrectionsWiring Guide Bill Of Materials Design Guidelines for the ASM-2 Basic Module Connections 3D Model

Schematics and PCB Overlay

ASM-2 Builders Corner Demonstration 1 of an ASM-2 built by STRAT-1Demonstration 2 of an ASM-2 built by STRAT-1

Copyright 2000. All rights reserved.     Revised: January 15, 2019