Guild Foxey Lady Transistors

[mcasey1]

I'll get right on it.  I see these errors as ways to force one to learn how to debug.

[nightingale]

Hi,
I built this one from the same vero layout. I did notice the wrong cap value. I omitted the stuff that is not on the original schematic [protection diode/ extra 47uf cap from +9v] My circuit seems to be  ok with a pair of 2N5088's. I tried some tin can PN2369's [Hfe 90], but I went with the 2N5088's for a nastier fuzz. If i turn the fuzz control down really low,  I get a little bit of gating, but in a good way. It is a really cool circuit IMO. The only draw-back is that it does not clean up as well as the mosrite fuzzrite, which is in the same family?

hope this helps,
ry

[mcasey1]

Here are the values.  R1 corresponds with R1 on the layout, R2...etc.  refer to the layout.  I removed C4 and the diode.

R1=0/0
R2=0/.62
R3=8.96/.62
R4=8.96/.09
R5=0/0
R6=0/.72
R7=8.97/.73
R8=0/.13
R9=0/0
R10=8.96/.22

C1=0/.62
C2=0/0
C3=0/.09
C5=.09/.72
C6=0/.13
C7=0/.22

Didnt re-measure transistor voltages, or anything off the circuit board.  If I end up needing to I can, just let me know.  Thanks.

[Pedal love]

Make sure all the leads are goin to the right places and the transistor leads are connected properly.pl

[mcasey1]

Yeah its not that.  I have checked and checked and re-checked parts placement, track cutting, orientation. 

[R.G.]

R1=0/0

Good - it's the pulldown, should be 0V on each side.

R2=0/.62

Hmmm... This point really should be at about 0.82V. It's a bit low.

R3=8.96/.62

And this one shows the same low-ness on the base.

R4=8.96/.09

Collector resistor is connected at both top and bottom.

R5=0/0

Ding! We have a problem. R5 should not have 0V on both sides. It should have a fraction of a volt across it. I think that R5 has a short across it - perhaps soldering problems, perhaps a shorted C2. Check with your ohmmeter between the transistor emitter and ground. If it's not 680 ohms as R5 should be, then you have a short that needs to be removed. That will clear up a whole lot of ugly blatting distortion.

R6=0/.72

Hmmm... marginally low, not as bad as Q1.

R7=8.97/.73

The upper bias resistor is connected OK.

R8=0/.13

Mmmm... a little emitter voltage, close to the nominally expected 0.16V.

R10=8.96/.22

The collector resistor is connected on both ends, but is too low at the collector. Is that resistor by some chance 220K instead of 22K? Check it with an ohmmeter.

R9=0/0

Pulldown resistor, should have 0V both sides.

C1=0/.62

OK, blocks the first base's voltage from the signal input

C2=0/0

Possibly bad C2 or shorted by the same problem as the emitter of Q1.

C3=0/.09

Consistent with resistors.

C5=.09/.72

Consistent with resistors.

C6=0/.13

Consistent with resistors.

C7=0/.22

Consistent with resistors.

[Dragonfly]

One thing RG taught me long ago (whether he knows it or not) is that no matter how much you "think" you did everything right, if a verified circuit isn't working, then Mother Nature is telling us that we are wrong. I learned that on a EA tremolo debug...though I didnt realize it, I had the LED backward. Everything else was correct.  Which brings us to............................

Ususally when something isnt working, its some ridiculously small error.....but a "small" problem is enough to shut a circuit down.

RG has you "on the right track" !

[mcasey1]

You are correct.  A very tiny solder bridge (had to use magnifying glass) between the tracks.  It was right by R1, so the first two tracks from the bottom.  That cleared a lot up and I am thankful to all who helped.  The horrible blattiness is gone, replaced by a nice nasty almostmodulating fuzz.  The attack is wierd, I dont know if it is supposed to sound like it does (kind of ring modulation-y) but it sounds cool.  The fuzz control is wierd to me.  It seems like more of a tone control than a gain control, gettin very dark to one side.  Is this normal?

Rechecked C2 its 0/.18

680 R across emitter to ground

22K resistor verified.

[Meanderthal]

 Yep, that's more or less what the fuzz pot does- sorta tone and gain mixed. Congrads!

[mcasey1]

R.G., by any chance did you get these swapped?  Isnt R10 the Pulldown and R9 the collector?


Quote
R10=8.96/.22
The collector resistor is connected on both ends, but is too low at the collector. Is that resistor by some chance 220K instead of 22K? Check it with an ohmmeter.
Quote
R9=0/0
Pulldown resistor, should have 0V both sides.

[R.G.]

Nope. By both the illustration of the layout and by the voltages, R10 is the collector resistor for Q2 and R9 is the pulldown.