Chunk Chunk hiss with power adapter

[Jazzman]

Hi all, just after some advice with the chunk chunk board I've just built. This is my 2nd Chunk Chunk to date - built for a mate as a trade for a Fernandez Sustainer kit. Anyway, used shielded wire this time for the board in and out, as well as switch in and out... definately worth it... cleans up so much of the noise! I've used a simple 100ohm + 100uf cap on the DC jack as power filtering. And biased all the jfets to 4.25v, then reduced trimmer 1 untill the oscillation went away (with the vol and gain all the way up). The pedal works fine on a battery, however when I plugged the 9v wall adapter in the pedal squeals... Just wondering what should the next step be? Do I need to re-bias? What would cause the noise when it's generally quiet from the battery? Thanks for your help, guys. 

[Jazzman]

*BUMP*

[mgwhit]

Your title says "hiss", but your text says "squeal".  There's a big difference.  Which does it do?

There's always more potential for noise when you're using power from an outlet rather than from a battery.  A battery is a steady DC supply dedicated specifically to the pedal, whereas an adapter is transforming AC to DC (a potential source of hum) from a circuit that is probably shared with several other devices that could be causing all kinds of noise in the power supply.

Are you using a dedicated adapter, or is it powering other pedals, too?

[Jazzman]

Yeah, was a squeal, but it's magically disappeared?  Can't complain... ha ha Cheers anyway mgwhit

[nzCdog]

Its a very high gain circuit, so more susceptible to noise or dirty power.  I once experienced an intermittent 'squeal' or high pitched whine when testing out the Chunk Chunk I built.  It ended up being interference caused by our plasma tv in the other room... But other than that it is a remarkably quiet high gain pedal.

I've noticed that our dishwasher makes noises in my pedalboard when its going too lol