After spending more time using the tube vca, I found the output was
not high enough to work well with other modules. So I changed the
feedback resistor of the output amp to 2.2K and added a 1K gain
resistor resulting in an output of around 8.6Vpp. This also improved
the range of sounds when using feedback (I normalled the output to
the second input using a switched jack).
I also wrote things up for the Electro-Music forum:
http://electro-music.com/forum/viewtopic.php?p=187439#187439I think I'm done now :)