Rangemaster Hiss Help

[f50jack]

I recently built a Dallas Rangemaster using the schematic from Fuzz Central. http://fuzzcentral.ssguitar.com/rangemaster.php

It works great however it sometimes just randomly starts to hiss and create a fuzz like sound. It lasts a little while no more than a few minutes and then just goes back to normal. Has anyone had any similar problems? Any ideas how to fix this.

Thanks Jack

[petemoore]

  I had a hissy transistor in RM's at least thrice, you know, now that you mention..it's been so long it seems I do have some vague recollection that intermittent changes in amount of hiss....aughhh...probably not the same thing anyway.
  Swappin' that one...for the other-other ones...they were all GE transistors and all of them were different from one another, at least slightly, it's possible to get two that are very similar, they seem to hiss, on average, more than SI's.
  I reversed a cap, but replaced it, don't remember it really being a hiss problem.
  Caps tend to do 'intermittent' when connected sometimes, resistors don't.