EH Mistress filtering

[zeta55]

Hi.
Can anyone point out too me why I've got so much svosching noice through my standard mistress.
I've checked all the caps on the output of the SAD1024.
Also all ectrolytic caps are changed for new ones.
When trimming the internal pots it starts flanging at the same time as the noice appears.
I really could use some help here as I feel totaly stuck.

http://www.fortunecity.com/tinpan/humperdinck/223/ehmist.gif

[Mark Hammer]

The reason why you hear the noise WITH the flanging is that flanging IS noisy, and you have to do a lot to keep the noise away.  This schem lacks much of the lowpass filtering that is needed to keep clock noise and anti-aliasing noise out of the signal path.   It is one of the earliest Electric Mistress designs/issues, but not one of the best.

[zeta55]

Hm... So I'm searching for a fault that's not there. I'm thinking of redesigning the cuircit a bit more too the deluxe version but I'm not shure it's worth the effort. Time will tell.