Stereo volume control

[Ouroboros]

Originally posted by Hybrid fourdoor
So can you use a digital pot with an active crossover circuit, that way you have very high resolution and consistant selections?

If you use a DSP-based active crossover (like the Behringer) and feed it after a conventional volume control in the pre-amp, then as you reduce the signal level, you're reducing the resolution of the signal in the DSP. If you feed the crossover at a high level of signal (below clipping of course!) and put the volume control on all six analogue outputs going to all the power amps, then the DSP is always working at full resolution. As 6-gang pots aren't around, the design idea on the article can easily be extended to slave any number of up/down digital pots from the one master rotary control.

(It almost worth laying out a pcb for it and selling a few! I'd use Maxim/Dallas digital pots rather than the ones shown, but that's no problem)

[tcpip]

Originally posted by Ouroboros
(It almost worth laying out a pcb for it and selling a few! I'd use Maxim/Dallas digital pots rather than the ones shown, but that's no problem) [/B]

Yes, I too find the circuit very tempting. The only problem I feel we should watch out for is keeping the pots in sync. If you have three or six pot chips, and due to some reason (reasons are available in the Xicon app notes, related to power-on glitches), the chips fall out of sync with each other, then you'll have a very irritating problem. And there will be no easy way to get the pots back in sync. Therefore, you have to choose pot chips which ideally don't have NVRAM to remember the volume setting, but reset to a preset value (ideally zero volume) at start-up each time. Then this comparator-based circuit can bring all the pots up to the manually set level.

Just my ten-paise.

[indoubt]

Originally posted by ron clarke
Yep, thats why i use 2 pots.I have yet to find a truly equal dual pot.
ron

There is a panasonic pot where the "equality is guaranteed to be less than 0.4db

They are quite expensive (>50 euros) as far as I know