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ASM "Ultra" VCO



The idea with this VCO design was to made a very "musical" and warm module like ASM1 VCOs but with a much better stability and more vwaveform outputs

First prototype picture (was not fitted with the Hard Sync stage at this time...)


It is the core of the ASM1/Electronotes VCO, but with an improved "ultra stable" CV expo stage and wave shapers to get Triangle and sine waveforms from the saw output...


  • coarse & fine tune pots
  • Pulse Width and PWM pot
  • 1PWM input
  • 1/VOct input
  • 2 CV FM inputs
  • 4 waves outputs ( saw, pulse with pwm, triangle, sine)
  • 2 sync modes ( hard & soft) with one sync input

From the same pcb it is also possible to build 3 basic kind of VCOs : depending part soldered or ignored it can be wired as :

  • clone of the ASM1 VCO
  • clone of the Electronotes VCO
  • ASM ultra VCO ( improved cv expo + waveshaper+ Hard sync )

The pcb has been routed to get best perfs on a single side pcb...

This VCO sound as good as the Electronote /ASM1 VCO ... Normal somewhere because it is the same core but with a "slightly" better stability :)




ASM "Ultra" VCO pcb + Construction manual
are available on order


© Marc Bareille 2005