Hi pitch noise on a King Midas

[musikelectro]

Hi everybody

I have a hi pitch noise on my king midas, anyone have this issue. The noise is always there like an oscillation, probably coming from the -9v inverter.

Any solution, bypass cap on -9V maybe.

Thanks

 

[Robert]

Just to be sure, does your charge pump have the S suffix? ICL7660S

 

[music6000]

Built this awhile ago. No issue, Used ICL7660SCPAZ, S being the must have as noted above.

 

[zgrav]

good question about the charge pump. if the part is correct with the "S" suffix, make sure that pin 1 and pin 8 of the charge pump are connected (they both should go to 9v on the circuit). That connection between those pins changes the frequency of that whine to (hopefully) put it out of hearing range.