Minimize noise with Digital Pots.

[william]

I'm thinking about using eight 10k digital pots on a Boss GE-7 to replace the sliders.  I've read in various places that zipper noise could be a problem but I don't plan on changing the values while playing.  The other issue is possible noise from the Arduino board.  Has only got advise on using digital pots on in a project like this.

[Digital Larry]

I'm going to guess that if you really wanted a programmable graphic EQ pedal, and you put any sort of value on your time, you would simply buy one:

http://compare.ebay.com/like/190857621020?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

However, that's not always the driving force behind our desire to do things here, is it!   

I'd suggest reading this for general info about Maxim digital pots:

http://www.maximintegrated.com/app-notes/index.mvp/id/1828

I bought some awhile back hoping to do something with a Launchpad and some analog effects blocks, but that hasn't happened yet.

Anyway, my off the top of the head summary of possible issues with digital pots in audio:

1) Resolution (# of steps)
2) Voltage range - some/most of these are not going to be happy with negative voltages or voltages that go above the supply rail.
3) Taper - most I've looked at are linear taper, which would be preferable for a graphic EQ.

[william]

I want to try a midi controlled guitar amp and I'm thinking of using an arduino to control a set of digital pots hacked into a Boss Eq-7.  The EQ would then be put right after a cathode follower in the amp utilizing it as an FX send as in the Slo-100.  The output of the EQ then would be the FX send out of the amp into what ever else you want in the loop.