Help with my fuzz clone

Started by mortem, August 05, 2013, 11:42:54 PM

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MaxPower

#40
What do you mean by bad?

Anyway, compare the schematics for the pnp and npn versions (http://fuzzcentral.ssguitar.com/fuzzface.php). Reverse the battery so that the -9V is connected to ground, reverse the diode, reverse the polarized capacitors, and replace the 470 Ohm resistor with a 330 Ohm resistor. I think those are all the changes you need to make.

Also, make sure you check the pinouts for the transistors (Emitter, base, collector) as they may be different than the transistors you used in the pnp version.
What lies behind us and what lies before us are tiny matters, compared to what lies within us - Emerson

mortem

thank you i changed everything, but the voltages are bad, in the schematich there are a lot of holes for the trimpot, where should the wiper supossed to be wired?

mortem

i'm getting tired of this, i measured the voltages of q1 and q2

Q1
Collector
0.02v
Base
0.58v
Emitter
0.0v
Q2
Collector
0.02v
Base
0.02v
Emitter
0.58v

???

MaxPower

Are you using a regular pot (three leads)? If so the wiper is connected to one of the end leads (of the pot)  and both of those are connected to the collector of the transistor (Q2). The other lead of the pot is connected to the 330 Ohm resistor and .01 uf capacitor.

From a previous post in this topic (by LucifersTrip):
from ggg:

Q1
Collector
-1.4v
Base
-0.6v
Emitter
0.0v
Q2
Collector
-4.5v
Base
-1.4v
Emitter
-0.8v


Your transistor readings should probably be close to those (except that they should be positive now that you've changed to the npn version). Try adjusting the trim pot (10 kOhm) and see if the voltage reading on the collector of Q2 changes. If it does, try to set it to about 4.5 to 5 Volts.

What lies behind us and what lies before us are tiny matters, compared to what lies within us - Emerson

LucifersTrip

Quote from: mortem on September 01, 2013, 04:44:25 PM
i'm getting tired of this, i measured the voltages of q1 and q2

Q1
Collector
0.02v
Base
0.58v
Emitter
0.0v
Q2
Collector
0.02v
Base
0.02v
Emitter
0.58v

???

I think you're at the point where showing us some clear pics (as mentioned earlier) of what you're doing will help the most.

check out the schematic



you have the voltages of Q2 B & C the same, which means they are shorted (connected)...of course, they shouldn't be
always think outside the box

mortem

thank you so much, is alive, the problem was a bad wiring between the fuzz pot wires, now it works perfectly, i only have a question, it sounds a bit dirty, is because of the transistors or i can adjust that with the trimmer?

smallbearelec

Quote from: mortem on September 03, 2013, 09:47:49 PM
thank you so much, is alive, the problem was a bad wiring between the fuzz pot wires, now it works perfectly, i only have a question, it sounds a bit dirty, is because of the transistors or i can adjust that with the trimmer?

The 2N2222A is a medium-gain device. It's usually fine for Q2, but a pair will likely sound harsh. I suggest using a lower gain part for Q1 and then tweaking the bias:

https://www.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm

MaxPower

Mess around with the Fuzz pot and see if you find a setting you like. Or follow smallbear's suggestion. Also, did you adjust the 10k pot to set the collector voltage of Q2 to about 4.5-5.0 Volts? The link smallbear posted is a good read.

I've never built or played a fuzz face so I don't know how it sounds. I've built two Tweak-O's (https://www.smallbearelec.com/Projects/TweakO/TweakO.htm), one with silicon diodes and one with germanium diodes. I think the germanium version sounds a lot better than the silicon version. If you're up to building yet another fuzz face, try it with germanium transistors.
What lies behind us and what lies before us are tiny matters, compared to what lies within us - Emerson

LucifersTrip

Quote from: mortem on September 03, 2013, 09:47:49 PM
thank you so much, is alive, the problem was a bad wiring between the fuzz pot wires, now it works perfectly, i only have a question, it sounds a bit dirty, is because of the transistors or i can adjust that with the trimmer?

Cool...now DEFINITELY make a note of the voltages when it's working. then, you have a reference if you have to troubleshoot again.

Before you worry about it being too dirty, make sure you're at least close to the good voltages posted earlier.

A common method of removing harshness from the si version is to place a small (around 50 - 200 pF) cap across either Q1 or Q2 B and C.
Start with Q1.

pF = picofarad
always think outside the box

mortem

i added a cap between Q2 and now sounds great, thank you very much to all  :icon_razz: