VCA-3B

Dual 13700 linear VCA - design by Paia

Courtesy/Thanks to: Resonant Frequency and Paia

Description: After the CA3080 went obsolete, I began looking for a simple VCA circuit to replace the design used for VCA-2A. Both the NJM13600 and NJM13700 are still available from New Japan Radio, so I thought they would be good OTAs for experimentation. I drew a circuit board of a dual VCA, with the design taken from the Paia Fatman (although the fatman only has a single VCA). You may download the schematic for VCA-3B here. Please note that the board layout is a component side view, not a solder-side view.

I'm quite happy with the results: Quiet operation and acceptable CV feed-through. I may decide to revisit this design later an add a 2 transistor expo converter, and perhaps add adjustable make-up gain on the output buffer.