SOLVED Double Jeopardy: high pitched whine (isolated power supply)

[slowpogo]

I built the Double Jeopardy and it works great, except there's a faint high-pitched noise when it turns on. The noise gets louder as I raise the gain knob. I have a Onespot CS12 power supply and the DJ has its own output, not daisy chained. The whine is there even if it's just guitar>Double Jeopardy>amp so I think the pedal itself is causing this.

I didn't notice it right away because if I run the boost into a dirt pedal, the high pitched whine goes away. But if I want to boost a clean signal it's obvious.

any idea what might cause this high pitched sound? Is it worth trying different transistors or diodes?

 

[slowpogo]

is there a place in the circuit where adding a tiny cap (100pf) might reduce the noise?

 

[music6000]

What type & where did you get the Charge pump ie TC1044SCPA or TC1044CPA?

 

[slowpogo]

I used TC1044SCPA, it's from either Mouser or stompboxparts. Either way I'd assume it's genuine. I have others I could switch in, I'll try it, thanks!

 

[slowpogo]

I tried a different TC1044, and also added some extra insulation between the pot and the board. It's a double-decker pot and my regular plastic pot covers don't fit well, even after cutting a notch, so I had just put some electrical tape on the back. I added a few more layers.

The whine is gone! I guess it was either a bad IC, or not enough insulation against the pot causing problems. Thanks again, not sure why I didn't even think about the charge pump.

 

[hamerfan]

I tried a different TC1044, and also added some extra insulation between the pot and the board. It's a double-decker pot and my regular plastic pot covers don't fit well, even after cutting a notch, so I had just put some electrical tape on the back. I added a few more layers.

The whine is gone! I guess it was either a bad IC, or not enough insulation against the pot causing problems. Thanks again, not sure why I didn't even think about the charge pump.

Great, glad to hear that it worked for you. Please mark it as solved!