I’m facing a strange problem with the TC : after aprox. 10 minutes of use ( great sound ), the gain starts  dicreasing together with the increasing of an unpleasent distortion. Also, the sustain disappears and “pop’s”can be heard.
There is no significative change in the battery tension neither in the D, G, and S JFET’s voltage values.
Anyway, I changed ( and rebiased ) the FET’s ( one each time ) and tried different batteries, but the problem occurs again. It doen’s matter if is used MPF102 or BF245A
I belived could be the 100 uf electr. cap , maybe a problem with its leakage current, but I also changed it and there is reincidence of the problem . No overheat of any of the components could be noted.
What is interesting is that if I let the TC turned off during let’s say 10 min, it  starts well and then, well, the problem occurs again.
Does anybody have na idea how to solve the problem ? Thanks for the help.

Them kinds I hates...
 uh electro cap... :?
 You use new ones?
 If you move the pot shaft, and no funny business, then so be that.
 Could be a cold solder.
 Could be a transistor, did you recheck bias when the problem reared it's ugly head :?:  
 I had a bad 10k once, yupp...it had R like a wire[?], but, I seriously doubt you have any bad resistors...I think that one got hot HOT or something...I've never heard of such a thing. :roll:
 If the Tranny's voltages look good, I go with cap or cold solder, even cheepo switch...you can usually tell that tho. SOunds like a leaky cap or incomplete solder or connection...somewhere.
  :evil: Littel things can be hard to find the solution to sometimes. Flex the board gently while its actin up, and see if anything changes. Tap on the caps [electro's expecially] with a hard piece, lightly, while the funny stuff's going on.

Erio,

Try reheating the solder joints.  If that doesn't fix it, look into the caps, espeically the electrolytics.  You may have a bad one in there somewhere.

Good luck.