[sdiy] Digital / Analog Noises

[Bill Berzinskas]

Hello everyone..  as you might know by now i've been heavily modifing the adv-bass circuit..   so currently, ive got it running off of 5v, and got the digital pots all working..   Although, i'm having a few problems with noise..    

First..   At the final output stage, I am getting noise, although not before it..  This sounds like it could be digital, or it could just be a really low SN ratio..   So it's getting into the summing matrix somehow..   I've changed this to just a regular non-inverting summing amp..   which seems to me to be ok..    Any clues? 

Also,  I'm using the oscillator design from the LM158 Datasheet (Same setup as the DS-7 Clone)..   And i'm getting a small bit of the square wave into the signa..  whats up with that?!   i'm tinking it has something to do with the virtual ground setup..  but i'm not sure..   Anyone?   :-)

Also, I can hear clicks when i change a digital pot.. i'm thinking this is simply because it's stepped, but they seem rather loud.. what can i do about that? 


And while we're on this subject..  what precautions should I take in layout, construction to help curb these problems? I'm thinking of construction the Analog and Digital section on seperate boards and interconnecting..  Would def be easier on me as far as working on it.. anyway..  any input would be awesome! 
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