This is a seven-input waveform mixer using THAT 2180 VCAs, with OPA 2604 for the mixers.
The module is a simple repanelling of a pair of L-1 2180 VCA/mix boards.
The output of the first mixer is used as a submix send. The submix return uses one of the four inputs on the second board.
Because of this, eight CVs are needed: four for the first four waveforms (the flat-topped ones, N C G g) which are submixed and sent to the mixer send. This is normalled to mixer return together with the other three waveforms (O, 8, S) for a second, four to one mixdown. Therefore the eighth CV is for submix level.
Because the wavemix controller will be in a separate skiff, it is better to use balanced connection to transfer CVs. 8 balanced lines fit on a Tascam DB-25 connector. Use the Hinton impedance-balanced circuits with close-tolerance matched resistors.
The VCA response is somewhere between linear and logarithmic. From the designer, here is a the response table:
