[Possum]

The digital pot, DS1802, that I'm using is very sensitive to emissions from the power supply circuit I have. The closer the pot is to the circuit, the louder I can hear a clicking noise, a little farther away the clicking completely gone except at certain volume steps. Is there some kind of "shielding" that'll block out the power supply emissions that the pot is picking up? Layers of aluminum foil wrapped around the digital pot circuit didn't do anything, so it's probably not EMI interference (if this is what the metal shielding is intended for).





OT:

BTW, I'm happy that HeadWize was able to recover and bring back the forums, but it's too damn confusing to figure out which one to use. It'd be lame to duplicate every thread you create because one you're not sure which users from which forum can respond, and if duplicate threads were posted, someone would eventually comment on how many of the same posts appear on both boards.

 

[Apheared]

Do me a favor... ground your AGND and DGND together before they actually touch ground. See what that does. I had a similiar problem, where when moving volumes you heard a little "chccch" sound at each step... you could easily count the volume going up or down... after switching my grounding layout, it went away completely.

edit: I may end up losing my moderator status with such outspoken radical views but I think DIY should remain the territory of HeadWize. Chu has gone to great lengths to assemble the projects section and many ex-everything types that have gotten past the "what is best?" stuff only read DIY and only once and a while read the other threads... of course a loser like myself will read and question and answer and rant on both boards equally...

just my 2pF

 

[Possum]

Hmm, with the first DS1802 I used (before burning it out), I had the DGNG and AGND grounded together, but didn't notice what the grounded AGND did. I'll give it a shot...

10 minutes lates:
Adjusting the volume now produces no noise. Edit: Spoke too soon, power supply clicking is still audible.

I forgot to mention, the noise is similar to what others experience with analog pots where at the low and high extremes, there's no noise, but there's a noise while the pot is in a middle position. At low and high volumes, the noise is completely gone - it only comes out in the middle settings.

 

[ppl]

What opamp are you using. A Bipolar input type will produce this type of sound since the Chip is not a continious Resistor like a pot is but in fact a Switched Attuator that just happens to use electronic rather than Mechanical switching. This being the case the High Bias current of the Opamps input stage will cause this type of noise. If this happens with a jfet input type the Oscilation of your amp of your amp is being subjected to RFI interfearence. As far as the Powersupply noise goses NU-Metal of Steel are good at Low frequency and magnetic interfearence. Copper and Aluminium are not Good for this but are Exalent for the High frequency and RF emmitions. Next install ferite beeds upon the Hots of both your inputs and outputs place at the point of chassis exit.