GGG Tubescreamer Debug

[jmdfd415]

Ok I have went over my work quite a few times and everything is in the right place and all wiring is correct.  Here is the link to the screamer I built http://generalguitargadgets.com/pdf/ggg_its8_lo.pdf  and the mods I did are here http://generalguitargadgets.com/pdf/ggg_its8_mods.pdf  I did the asymmetric clipping mod, amz fat mod, and the keeley mod without the diode lift.

Heres some of the voltages im getting:
Battery: 9.18

Q1
E: 0.15
B: 0.69
C: 9.18

Q2
E: 0
B: 0.69
C: 9.18

IC:
1: 1.43
2: 0.82
3: 0.77
4: 0
5: 1.37
6: 1.40
7: 1.40
8: 9.18

They bypass is working fine.  Whenever it is on the sound is very farty sounding and bassy.  I can tell a difference when I turn the knobs.  Thanks for all your help guys!

Edit: Sorry forgot to say that I am using 2n3904's for the transistors and a jrc4558d all from smallbear.

[petemoore]

Ok I have went over my work quite a few times and everything is in the right place and all wiring is correct.
  ?
   Here is the link to the screamer I built http://generalguitargadgets.com/pdf/ggg_its8_lo.pdf  and the mods I did are here http://generalguitargadgets.com/pdf/ggg_its8_mods.pdf  I did the asymmetric clipping mod, amz fat mod, and the keeley mod without the diode lift.

Heres some of the voltages im getting:
Battery: 9.18

Q1
E: 0.15
B: 0.69
C: 9.18

Q2
E: 0
B: 0.69
C: 9.18

IC:
1: 1.43*
2: 0.82*
3: 0.77*
4: 0
5: 1.37*
6: 1.40*
7: 1.40*
8: 9.18
  Pins 4 and 8 are correct.
  The other pins are not biased.
  There is a miswire or misvalued resistor in the bias network.
  I would start at the voltage divider [two equal value? resistors seriesed across power supply rails], measureing the Vbias voltage [powered], then each resistors [unpowered] value there...continuing on through the bias arrangement measureing resistances...'through' the resistor *connections if possible [...not on the resistor lead. this not only gives R value but assures the resistor leads 'are actually conducting where their leads look to be connected].

[jmdfd415]

Im not really sure which ones those are so I guess tonight when I get back from work I will just check all the resistors and see what I find out. 

[R.G.]

Yahhoo!! Good going, Pete!

I don't have a thing to add to that.

You go, guy.

[jmdfd415]

Ok I found a 10k resistor that was bad and changed it now it has a decent sound but something still doesnt seem right.  Here are the new voltages I am getting.
Q1:
E: 2.95
B: 3.5
C: 9.18

Q2:
E: 2.96
B: 3.48
C: 9.18

IC:
1: 4.58
2: 4.67
3: 4.58
4: 0
5: 4.58
6: 4.58
7: 4.58
8: 9.18

Its still got a kinda broken up sound with bassier strings.  Thanks for all the help so far guys.  I looked at what the voltages are supposed to be on ggg and everything seems ok except for Q1 and I am not really sure what to do.

[jmdfd415]

anybody?

[jmdfd415]

Sorry to bump again but I really need some help on this.