Voltage processor

This is a voltage processor module based on designs by ARP and MFOS.

There are two sum sections: One has four inputs, two with attenuators (normaled to -10 V and +10 V) and two with fixed unity gain; the other has two inputs, one with attenuator (normaled to +10 V) and one with fixed unity gain. Each sum has two outputs, normal and inverted.

There also is a lag processor section. Switches allow selection of slow or fast ranges and RC or linear ramping, and a knob adjusts the lag time.

The sum sections are derived from the ARP 2600 schematics. Differences:

  • Obviously, this is a module, so there is no normal connection to keyboard CV; instead the second input of the first sum is normaled to +10 V.
  • Added second inverting stages for normal plus inverted outputs.
  • TL07x op amps in place of LM301.
  • Added series output resistors.

The lag processor is based on a section of the MFOS Multi Function Module. Differences:

  • Common input and output for both linear and RC circuits.
  • Shorter minimum linear lag time.
  • 1k series resistors on outputs.

Github repo:

Some boards and panels will go up on Tindie soon.

Blog post: Processing voltages – Analog Output


I m going to get at least one or 2 from Tindie, still trying to get the hang of doing gerbers and such. Ray Wilson would be proud , he was a mentor and a good friend of mine , I did him alot of business at nearby Jameco electronics , here in the Bay Area, your work too is fantastic and beautifully done . A given pat on your back.


What was Ray’s relationship to Jameco?

I bought parts and some special items that were IC’s made and rare in bay area.

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