Kittywampus Charge Pump Whine

Tremster

Member
I built the Kittywampus (Mr. Black Thunderclaw) that whines like crazy.
The pedal calls for an LT1054 charge pump, I used an LT1054CP (isn't that the only 1054 you can get?).
If I put in an ICL7660SCPAZ the pedal is quiet and works fine.
It's weird that the "correct" IC doesn't work and the other one does. Should I just leave the 7660 in? Get a different 1054?
Can I link or cut some pins on the 1054 to make it work?
Anything else to consider if I leave the 7660?
Thank you.
 
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Yep - not all the LT1054's are the same and not all the 7660's are the same, when it comes to hearing sub harmonics of the internal clock / switching oscillator. IDK if it is shielding, filtering or both. All will step up the voltage exactly the same, but only particular suffix types will be silent.

That is why I exclusively use the ICL7660SCPAZ. Functions reliably.
 
There will be a trace in order for the the 7660SCPAZ to work correctly!
It's the only one I use & have recommended others that have had issues with the TC1044S with the same issue you had here.
The only advantage the LT1054 is it can handle up to 15v input & double to around 28v + -.
 
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