Finally taking the time to write about my definitive Dual VCA module, after 2 previous less successful iterations…
This one comes with VC panning and optional limiting and clipping distortion modes. It’s intended use is as a stereo audio output VCA, but of course it can also do general purpose VCA duties. It pairs nicely with the Output module, so I filmed a little demo explaining the features with the help of the Output’s bargraphs: https://www.instagram.com/reel/DbrHDk0sg0o/?utm_source=ig_web_copy_link&igsh=MzRlODBiNWFlZA==
The module’s functionality is achieved with an actual pair of VCAs per channel. This is why there are 4 identical plug-in VCA submodules on the back. The “tier 1” VCAs respond to the dual CV and offset controls, while “tier 2” VCAs are normally fully open, unless you manipulate the Pan knob (center = neutral). If CV is plugged to the “CV P/T” input, the Pan knob becomes an attenuverter for that CV. The differences between Pan/Bal/Trem modes are explained in the video.
I forgot to mention the LEDs in the demo… they are meant to detect peak excursion above +5V (the “standard” modular amplitude for audio and bipolar CV), so you know that the output will distort if the Clip switch is engaged.
By the way, “Clip” means a couple of opposing 4v7 Zenner diodes are applied to both outputs, effectively limiting them to no more than +/-5V. In “Dist” mode, you engage 3v0 Zeners instead and bump the gain by 2x, which will heavily clip and distort the outputs and still limit them at +/-5V levels.
The calibration procedure is still t.b.w. (to be written), but other than that it’s a relatively easy build.