Tessera:
The Tessera is a 4VCA-mixer
The PCBs are designed to be mounted in parallel to the frontpanel.
Documentation:
References:
“Op amp Linearizes Attenuator Control Response” by Mike Irwin. See Pdf. Version
The Quad VCA/CV-Mixer Module by Marc Bareille
“An Analog Synthesizer for the 21 Century” VCA by Thomas Henry