I may not be understanding what you’re asking for, but, both of my VCAs with attenuation knobs (MI Veils and Zlob Vnicursal VCA) do the following:
- With no CV controlling a VCA channel, the knob acts as an attenuator of the input signal, whether that’s a CV or audio signal. In other words, the CV control of the VCA is normaled to 5v, and the knob attenuates the 5v control of how open the VCA is. In other other words, it acts like an attenuator.
- With CV coming in to control the VCA channel, the knob attenuates the degree to which the CV control affects the VCA being open. In practice, this also attenuates the volume of the output, since the signal opening and closing the VCA has a lower peak. I understand this as ‘normal’ VCA behavior, but I may be wrong.
In terms of mixing, I believe the Tangle Quartet and Vnicursal act similarly, in that the channels are summed to a sum/mix channel, but can be taken out of the sum and output individually by patching a channel’s output.
Veils mixes a little differently, in that summing happens top-to-bottom, and outputting from a channel breaks that summing. So in other words, if you have 4 inputs into Veils, and you patch out of outputs 2 and 4, channels 1 and 2 will be mixed in the 2 output, and channels 3 and 4 will be mixed in the 4 output.
AFAIK none of these allow a total control of volume of a mixed output from one knob. In other words, for Tangle Quartet & Vnicursal, you can’t control the sum/mix volume from one knob, and with Veils, you can have your channel 2 knob fully closed/CCW, and channel 1 will still output from output 2 if that’s how you have it patched.
I’m fond of the Vnicursal, mostly because it can be DIY’d for about $70-80 and it’s 6 channels in 8hp. That said, it’s laid out a little confusingly and the ergonomics using the trim pots for attenuation leaves a little to be desired. I used to not understand the attraction of the Tangle Quartet but thinking about it a bit more, it’s compact and ergonomic and clean, like most of ALMs designs.
