Low voltage VCAs for pedals

[Digital Larry]

I'm looking for something that can operate at +/- 2.5 volts.  So far I have only located the THAT 4315 analog engine, which is fine, although it has RMS detection circuitry that I don't need.  THAT 2150, 2180 etc single VCAs are nice but lowest supply voltage is +/- 4 volts.  Exponential voltage control is ideal.

[Mark Hammer]

Um, why?

[Digital Larry]

Well, aren't you the curious one.

I'm looking into making a tremolo that uses an exponential VCA controlled by a microprocessor that would run off 9V.  I'd just as soon run any analog supply voltages through one regulation stage, so I'd rather not run something directly off unfiltered 9V.

[PRR]

LM3080 will run on hardly any voltage. LM37000 needs another part-Volt.

Not an "exponential VCA", but trem does not need a 60dB range, and your PIC can look-up an exp function.

[ElectricDruid]

Yeah, I was going to suggest LM13700 too. The SSM2164/V2164 would be good because of the expo control, but it requires the same +/-4V minimum supply.
I think it's based on the same core as the THAT Corp stuff.

The Alfa AS3360 (recent CEM3360 clone) claims to be able to run down to +/-3V, but I've never tried it that low.

http://www.alfarzpp.lv/eng/sc/AS3360.pdf

(Full disclosure - I buy plenty of chips from Alfa and have them in my shop.)

Tom

[dschwartz]

What about using one pwm output of the mcu to drive a switch as a variable resistor?