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Topic: Reliable digital Pot for audio (Read 1 time) previous topic - next topic

stoopkid

So a while back I wanted to automate a guitar pedal with 5 pots. I was told that an actual digital pot chip is too noisy for an audio circuit. Also using optoisolation was really difficult, I never got it working right. I ended up giving up.

Has anyone done this? Is there a well documented way of doing it?

Thanks.

Chagrin


stoopkid

#2
Jan 27, 2013, 12:09 am Last Edit: Jan 27, 2013, 12:18 am by stoopkid Reason: 1
http://arduino.cc/forum/index.php/topic,74465.msg
This one is about the optoisolator. I never managed to find one with two outputs.

As for that chip, I know it says "audio" but I think that refers to the log taper. I actually want a linear taper. Does the word "audio" refer to the taper, or to it's ability to be used in audio applications? I mean I know it's a log taper but does that necessarily mean it is suited for audio applications?

Oh sorry, also the first issue I ran into was that my circuit uses 9v. So the digipot would need to be suited for that.

vasquo

it's got a built-in zero crossing detector and my guess is that's why they called it for audio use.

Personally, I haven't found a worthy digital pot for use in audio apps.... if you're making a one-off device, sure they'll be fine.

But if you'll be mass-producing gear that uses them, or creating a matched pair, good luck!  Check out the datasheet:

End to End resistance... for a 20K spec part, it varies from 15K to 25K.
That's a 25% tolerance!

dhenry

Quote
Reliable digital Pot for audio


Not sure if they are "reliable", but PGA23xx would be the gold standard for audio digital pots.

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