[sdiy] Anyone built the ELEKTOR VOCODER?

[Mike I.]

The ultrasonic PWM'd analog switch VCA technique  is the one employed in 
the Roland VP330 string machine/vocoder. Don't know if the Roland 
SVC-350 (or whatever the rack unit is called) uses the same approach. 
Rather ingenious way of getting 4 VCA's from one 4066. The Craig 
Anderton/PAiA  vocoder uses NE570 compander chips as a low-parts count 
method of getting multiple envelope followers/VCA's. The Korg VC-10 
vocoder uses the famous Korg one-transistor VCA approach  except instead 
of one transistor + one op amp per VCA it uses 17 transistors feeding 
one op amp (to handle all 17 channels)!
Mike