There are sexy, unusual modules that can be very interesting. Then there’s utility modules.
Not so interesting, but useful.
Here’s one:
The design for this started out as a clone of the voltage processor from the ARP 2600 synthesizer. There are two voltage summing sections and a lag circuit.
One thing that always bugged me about the ARP version is it had only inverted outputs. So my biggest modification was to add inverting stages to get un-inverted outputs too. The op amps were changed to TL07x, series resistors were added to the outputs, and since normaling to the keyboard CV can’t be done in a modular, I made the normal for the second input of the first summer +10 V.
I decided to jettison the ARP lag circuit in favor of something based on the lag section of the Music From Outer Space multifunction module. In addition to the more usual RC lag shape it can instead do linear lag. Unlike the MFOS module the two lag circuits share an input and output, with a switch to choose one or the other function. Another switch lets you select slow or fast lag ranges. I decided the minimum linear speed was slower than I wanted, though, so I changed a resistor to fix that.
Can you tell why I was glad I got a new bag of audio jacks last week?
Anyway, that’s the voltage processor module. Isn’t that interesting? Yes, it isn’t. The usual details and design files are here: https://gitlab.com/rsholmes/voltproc.
Analog Output 