VC mixer from OTA's

[Steven Varner]

Voltage Controlled Mixers:

I've had a couple suggestions about using OTA's for each channel of the 
mixer (similar to the EN-76/PCC option 3 VCA).  These would go into a 
summing node.  One email suggested using a final OTA as a buffer amp. I 
started thinking that maybe I could use 2 OTA's in parallel with all 
channels going in to both.  Then I could somehow have both a PAN input 
and a manual pan pot going between the bias input of those last two 
OTA's.  One OTA would lead to a right channel and one to a left.  The CV 
pan or the manual pan would shift the output from right to left channel 
for stereo effects.  Anyone done something along these lines?

Steve

  CV o-------OP---+-(controls)
                  |
  IN o------------+---OTA----+
                             |
                             |
  CV o-------OP---+-(contr)  |
                  |          |       +-----OTA------OP----o Right
  IN o------------+---OTA----+       |      |   
                             |       |      OP---+--> -15
                             +---OP--+           |
                             |       |      +----+ +15-Gnd Pot and CV--o
                            etc.     |      |
                                     +-----OTA------OP----o Left