Author Topic: Digital Pots  (Read 1877 times)

Dylfish

Digital Pots
« on: November 27, 2013, 04:50:06 AM »
Hey Guys,

Please excuse my ignorance in this subject but... digital pots.

I'm currently designing up a programmable looper system using relays and an Arduino. I had this idean that i could have a pot on it so at a flick of a switch i could attenuate my volume as if I were rolling it down on my guitar.

I then thought that instead of having a physical pot on the looper, I could use a digital pot and dial in presets before it goes through any pedals.



My question is with a signal running through a digital pot, will there be a degradation in sound quality compared to a "standard" analog pot? I'll obviously be able to bypass oit and what not but I just wanted to see your thoughts.

Cheers,

Dylan

(if anyone wants me to draw up what I'm thinking about then ask and ill scan it up!)

Digital Larry

Re: Digital Pots
« Reply #1 on: November 27, 2013, 10:16:24 AM »
Search through this forum for another discussion of digital pots within the past few months.

I have not done any circuit design in a few years, but the main thing to be concerned about with digital pots is the voltage range they accept.  They may only be happy with signal voltages between 0.5 and 4.5 volts.  Check the data sheets.  Outside of this range you are likely to get clipping which will give you a nasty distorted sound you probably weren't looking for.

Another thing to watch out is audible clicking as the the pot changes settings.  I believe that some digipots have a way to switch close to a zero crossing of the input signal to minimize clicks and pops.

Finally (that I can think of anyway), only a small percentage of available digipots are designed with a "log taper" arrangement making them more suitable for use as volume controls.  So if that's your intended use, be sure to find one designed for that.
Digital Larry
DSP tinkerer and former transistor twister