Sunking Squeal w/SCPA Chip & DC Power Issue?

[Roctopus]

Hello friends,

Like others, I've finished my Sunking build and noticed a high pitched squeal. After reading some threads on the issue, most seemed to have solved the problem with the 7660SCPA chip. However, I have the correct chip and am still hearing the squeal. Furthermore, the pedal only works correctly via 9v battery. When I've tried to power it using a DC power supply from my pedalboard I get a very large hum and the pedal becomes useless. Any ideas on how I can (1) get rid of the squeal and (2) eliminate the hum when using the DC power supply.



Thanks for the help gang!
Roctopus

[jkokura]

It may be that you still have a dud of a power chip. Have you tried a 1044 at all yet?

Other than that, it might be your DC supply itself.

Jacob

[madbean]

Yeah, is your DC supply a wall wart? 9v wall warts put out 9v minimum under load, but the actual supply voltage could very well be too high --12 - 14v. That could cause the problem.

[masterlk]

I just had the same issue with a DC wall wart that said it was 9v but when measured it was 14.97 or so. It provided plenty of hum.