Faultline buzz, crackle, sizzle

[insomniac2295]

So, I built up a faultline a while back. Just got around to testing it out and have found that there's a fair amount of high pitched hum to it. not overbearing like with some grounding issues, but more resembling feedback-type sounds. It also crackles some what, but intermittently. Sort of like the rhythm of a dial-up connection. Any ideas what could be going on here? Everything else works fine. I'm thinking this problem might be transistor related as there are so many of them in this particular circuit. Also, I should note that all of my transistors are socketed.

[insomniac2295]

Can an audio probe track this problem down? If so, what's the basic approach to tracking down noise?

[insomniac2295]

I snapped some video of the pesky noise in action. You can hear in the video that the noise is still quite prevalent while playing
https://www.dropbox.com/s/pgpe26cw66c142c/Video%20Feb%2017%2C%207%2025%2036%20PM.mov

[insomniac2295]

Anyone?

[nzCdog]

This sort of thing can be hard to track down, but assuming you've correctly assembled the pedal, it could be interference or a faulty part.  Firstly..  does it present itself in any of your other pedals/amps?   If you have a scope you could trace the signal and have a look for the presence of the noise.  Otherwise you'll have to use a method of deduction.

Audibly it sounds kinda like it could be harmonic interference.. eg from power supply, so you could try turning things off (eg battery-chargers/tvs/computer etc) to see if this has an effect.  Try a different power supply to see if that's the problem.  You could add a ceramic filter capacitor in parallel with your power rails inside the pedal, say 10-100nF from 9V to Gnd to help with this.

Otherwise could be a dodgy electrolytic cap, look for sign of leaking electrolyte or swelling as a visual indicator... or just replace them all, they're notoriously unreliable, particularly the cheap ones.  If you've socketed your transistors it's worth trying new ones also.  That's all I can think of for now.

Let us know how you get along.

[insomniac2295]

Thanks for your input! I used electros from Mammoth. I've used them in around 10 other builds without problems. The trannies I used are also from Mammoth, but a type I've never used before. That, coupled with there being 8 trannies in this particular build makes me think i should check that out first. Well, after I rule out harmonic interference. I've already done the visual check on the electros and they all appear to be okay.

[hoodoo]

Hi mate, i recently built a wolfshirt and had the same problem, changed  trannies a few times thinking that this may be the problem, no good still squealing like a pig. I was testing the pedal in line with other pedals on a pedal board using a boss power supply, as a bit of an after thought, decided to test it with a 9v battery connected externally, problem fixed. Try it with a battery and see how you go.
All the best, Matt.