A problem only described as the Death Hum

[Jhouse]

I recently made a Big Muff Pi with the layout based on Tonepad (http://www.tonepad.com/getFile.asp?id=94). I used the parts listed for the Green Russian style. I used .033 uf capacitors in place of the .047 uf, C5 and C8. I also installed a power sag option in it based on this (http://www.beavisaudio.com/projects/DBS/). When the effect is bypassed or when the pedals are all the way down, the pedal is completely quiet, not a single hum or hiss to be heard. When I turn the pedals up though, any of the pedals, a weird, loud hum can be heard. The sounds also get creepier depending on whatever knob I turn. At first, I thought this was the fault of the power sag that I installed, so I took it off. The problem still persisted. I can still get a great fuzz sound out of the pedal though. There is just a huge hum that is so loud you can even hear it when you are playing. Any ideas what could be wrong? I check my wiring. I grounded everything and used shielded wire for the input from the guitar to the pedal and for the effects in part of the switch. Help me out here?

[R.G.]

... Any ideas what could be wrong? I check my wiring. I grounded everything and used shielded wire for the input from the guitar to the pedal and for the effects in part of the switch. Help me out here?

check the wiring again

[Jhouse]

Well, I completely rewired the pedal after checking my wiring. I used this (http://www.generalguitargadgets.com/diagrams/switch_lo_3pdt_ig_dcjack.gif). It's doing the same thing it was earlier.

[CynicalMan]

What kind of power are you running it off of? Try it with a battery if you haven't already.

[Jhouse]

Just a Powerline Universal AC adapter. I tried it with a battery, no dice.

[Earthscum]

Bridged traces? Ground loop?

I had a fuzz that had hum and when I took it out of it's case it wouldn't hum. I isolated my in and out jacks and the problem went away. It didn't really make sense to me, but I think it was oscillating between the probably not so great connections between pots switch and jacks. Now I just use isolated jacks because I dig them, but that was the only one that really hummed and it was cured this way.

[edvard]

Just a Powerline Universal AC adapter. I tried it with a battery, no dice.

As in, it didn't work with a battery?
If it doesn't work with a battery and it does (with hum) from a power supply, you got probs my friend.

I've encountered the Hum of Death many times and more often than not it's a dead semiconductor.
I've encountered ground loop exactly ONCE in all my pedal-building (I count myself lucky...).

Check your transistors or op-amps, depending on which one you built, then go hunting for ground loops.

[Jhouse]

Alright, I redid the pedal using the same LAYOUT and using the same DYING BATTERY SIMULATOR. I also did a mod where I replaced D1 with an SPDT switch that lets me switch between types of diodes. I did find out that my previous power supply was faulty and that the noise was coming from that.....after I took the pedal apart and redid it. Darn my luck. Anywho, the new pedal worked for the most part but the LED wouldn't light up and sometimes the fuzz knob would make weird sounds. I discovered that the led was wired incorrectly and I just wired it the correct way. This made my LED light up, but now my pedal just makes a BZZZZ sound and get this, when I turn the volume knob, it makes the LED brighter! I have no idea what's up with this bad boy.

[Jhouse]

Update: I took out the LED. It seems like only the volume part of my pedal is working now. Hmm. I'll check my wiring again.