cheap linear digital pot search

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xplod1236

xplod1236

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Joined 2003
diyaudio.com
#1
I need some help finding a cheap digital pot( I need 14 of them). It will be used in an adjustable low pass filter, so it needs to handle ac (+/-). I don't want to use the pga2310, because that pot is logarithmic and not linear. I would prefer serial control and a dip package.

Does anyone have any suggestions?
 
#4
I think it depends on how many steps you need on the wiper. I was thinking about this too; there is a circuit idea in Electronics World that uses digital pots to set the frequency and Q of 2nd order state variable filters. It uses 256 step pots, and is scaled to give fs = 1 to 256Hz, and Q = 0.01 to 2.56. I thought an active crosover design using these would be very versatile, but (and there's always a "but") each stage uses 8 op amps and four pots; one for Q, two for f and one for level.

One thing I found on searching for suitable devices is that no distortion figures are given, so I'm not sure about their suitability for audio circuits. If they're anything like CMOS switches then they aren't that good.

We need someone with experience.😀
 
#5
I think it depends on how many steps you need on the wiper.
Click to expand...

That doesn't really matter for a sub filter. 256 would be nice, but 64 would work too.

johnnyx said:
...and four pots; one for Q, two for f and one for level.
Click to expand...

The circuit that I want to build uses 8 pots; 4 for f, one for q, one for phase adjustment, one for boost, one for boost frequency, and one for volume.

I will replace the volume pot with the pga2310, and all the other pots with digital ones. I want to build 2 of these (stereo), but I do not want to turn 20 pots to adjust one setting.


Edit: I checked out maxim again, and I found these 2 pots that would work: DS1868 and DS1267 . I found the DS1868 for $2.53 (if i buy 125 of them) and the DS1267 for $8.32, both at digikey.com.
Is that the cheapest I will get them for, or is there some other place that sells them cheaper?
 
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