Head Case Problem

[Baktown]

All,

I just finished building Melanhead's Headcase, but it is making a really obnoxious squealing noise when I try to play it.  If I back off the guitar volume, it will almost go away, but not quite. 

Does anyone have any suggestions where I should focus my troubleshooting?

Thanks in advance!

Axl Bundy

[foxfire]

i don't know the pedal but, when i get squealing first thing i do is twist as many of my wires as possible. you could have some cross talk going on and by just twisting the wires going to the pots can get rid of it. there may be more to your issue but it hard to twist or untwist them so it can't hurt to try.

[Baktown]

I use flat ribbon type wire (3 strands together), so I can't really braid or twist them.  Should I use single wires and then braid them together?

Also, I discovered that if I put my finger close to the input jack, but not actually touch the jack, the squealing goes away.

Axl

[wampcat1]

back the gain down a bit and see if the problem gets better.
What size gain pot are you using?
bw

[Melanhead]

I remember mine being tempermental when I first built it ... It was mainly a lead dress issue and the fact that R3 is such a low value. ( it's a bit high gain! )

I could be wrong but you may be better off with the single wires on this one ... I actually used shielded wire for the input and output, with the shield soldered at one end only, just in case.

I've only built one of these, so I can't say for sure if the problem would occur every time.  I did build another pedal called the "tweakbox" which allowed me to have one pedal emulate 3 different pedals I've built by using switches. I needed to use a 1M Gain pot ( because one of these three pedals did ... ) so to compensate for this change, R3 was changed to 1.8k and C4 was to .068uf ... I didn't have any squealing problems with the "Tweakbox" in Headcase mode.

It's still one of my favorite pedals, hopefully you can get it up and going ...

MartyMart built one as well and he never mentioned a problem with squealing ...

Hope some of this helps ... I'm not much on my theory, I know enough to get by ... I build with my ears