[sdiy] lots of VCAs on one PCB

[Tim Parkhurst]

On Mon, Nov 23, 2009 at 5:17 PM, John Mahoney <jmahoney at gate.net> wrote:
> The SSM-2164* offers four quality linear VCAs per IC. Building a VCA around
> that would be a good way to go.
>
> Are you sure that you want linear VCAs for a mixer, though? Volume control
> feels best with log response.
>

Actually, the 2164 contains four expo response VCAs. Perfect for most
audio volume control applications. For linear response, the most
common trick has been to combine two 2164 sections, as shown by Mike
Irwin. Thomas Henry also shows a similar trick to get linear response
from a 2164 in the "Analog Synth for the 21st Century" book (another
shameless plug, I suppose).

Still, this means that you can get 16 linear VCAs with eight 2164
chips. Each VCA will require three op-amps, so one quad op-amp will do
the trick, with one section to spare.


Tim (Member of the Shameless Plugs for Men club) Servo
-- 
"Sire, the church of God is an anvil that has worn out many hammers."
- H.L. Hastings