Author Topic: another Tubescreamer Debug  (Read 4919 times)

Rawkcraze

another Tubescreamer Debug
« on: January 02, 2012, 08:31:54 PM »
so i built the General Guitar Gadgets tubescreamer clone with the Keeley mods, 3 diodes, and a 1m drive pot.
i used 2n3904 transistors and a lf353p ic. 
C11 is a tant, all the rest are elec or film. 1uf are NP.
im currently getting a high pitched ossilation noise no matter what the knobs, or switch are at. the frequency of the ossilation does change when i turn the knobs or change the clipping, but doesnt ever go away.

voltages of the ic
1:4.7
2:4.7
3:4.7
4:0
5:4.7
6:4.7
7:4.7
8:9
 and trannys
1:
Col:9.5
Em:3.6
Base:4
2:
Col:9.5
Em:3.6
Base:4

funny thing is that i made another overdrive pedal yesterday and it does the exact same thing. is it a grounding issue?
checked all the cap's and resistors and none of them are bad..

thanks

Rawkcraze

Re: another Tubescreamer Debug
« Reply #1 on: January 03, 2012, 05:39:57 PM »
just to add to this, it also has this high pitched noise when its bypasses. so somethings obviously going through the ground or something.

Rawkcraze

Re: another Tubescreamer Debug
« Reply #2 on: January 03, 2012, 11:11:42 PM »
and just to add, when my guitar volume is all the way down, theres no ossilation at all. redid all the grounding the exact way GGG says to and it still does the same thing. im not getting any squealing at low volumes, but it still gets bad after 1/2 way.. any ideas?