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Sunking Squeal w/SCPA Chip & DC Power Issue?

Started by Roctopus, February 09, 2012, 08:12:42 PM

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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
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
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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.