Proper hFE for Mutagen Fuzz?

[DigitalZombie]

I laid this out on the breadboard to try it out, as I like to do if the circuit is simple enough. I'm having the same issue another user was with barely any sound unless you strike hard. I'm using all the correct value parts, and I even had some BC549B's lying around that measure around 315-320 hFE on a Peak Atlas. The same user suggested that this circuit is picky about transistor gain, but said he didn't have the ability to measure the transistors he used for Q1 and Q2. These are the voltages I'm getting:
Q1 c=7.14 b=0.631 e=0.01
Q2 c=0.352 b=0.649 e=0
Q3 c=0.056 b=0.6 e=0.07

According to the build doc of the Madbean LEFTA which I guess is closer to the original Os Mutanes, they used vintage transistors (didn't mention gain) but got somewhat similar voltages:
Q1. c=7.88 b=0.638 e=0
Q2 c=0.85 b=0.6 e=0
FWIW they use a trim pot on Q2c.

So has anyone successfully built this one and was able to measure their transistors?

 

[BuddytheReow]

Can you share the schematic so we can help?

 

[fig]

This may help..

Coda Coda Coda

 

[Coda]

I’ll measure my build in a little bit…

 

[Coda]

Transistors: 2n2222A
Q1: Hfe- 287
E- 0
B- .59
C- 7.4

Q2: Hfe- 287
E- 0
B- .62
C- 2.7

Q3: Hfe- 287
E- .05
B- .55
C- .07

 

[DigitalZombie]

Transistors: 2n2222A
Q1: Hfe- 287
E- 0
B- .59
C- 7.4

Q2: Hfe- 287
E- 0
B- .62
C- 2.7

Q3: Hfe- 287
E- .05
B- .55
C- .07

Thanks, Coda. I popped in some 2N2222A's for Q1-2 that are measuring around 200 on my tester and it's already sounding better, but not quite there yet. Even with the fuzz setting maxed it seems too fizz out a little earlier than I prefer. I'm getting a little over 2.7 on Q2c as well, but I'm going to stick a 10k pot on there and see what happens if I can get it closer to 1v.

 

[DigitalZombie]

And I'm back. 1v on Q2c seems to wrestle the most sustain out of it, even with single coils. The combined resistance of the pot and a 1k is about 5.9k, a single resistor value I don't have on hand, or course. Going to sort through my transistors and try different values.

 

[Coda]

And I'm back. 1v on Q2c seems to wrestle the most sustain out of it, even with single coils. The combined resistance of the pot and a 1k is about 5.9k, a single resistor value I don't have on hand, or course. Going to sort through my transistors and try different values.

I should have mentioned that I did make some substitutions….not for tone, though…I was just short a few components…

 

[DigitalZombie]

I should have mentioned that I did make some substitutions….not for tone, though…I was just short a few components…

What'd you change and do you like it?

 

[Coda]

What'd you change and do you like it?

Yes. I think it was a cap. I’ll look for my build thread.

 

[Chuck D. Bones]

Transistors: 2n2222A
Q1: Hfe- 287
E- 0
B- .59
C- 7.4

Q2: Hfe- 287
E- 0
B- .62
C- 2.7

Q3: Hfe- 287
E- .05
B- .55
C- .07

How did you manage to get three transistors with exactly the same hFE?

Q1 - near cutoff - collector voltage is close to the positive rail
Q2 - linear region - collector voltage is somewhere in the middle
Q3 - deep saturation - collector voltage is less than the base voltage

This is how it should be. If the collector voltage is too low, then the transistor's hFE is too high and vice versa. This is NOT a plug & play fuzz. More of a Goldilocks thing. You have to hand-select the transistors.

 

[Coda]

How did you manage to get three transistors with exactly the same hFE?

Q1 - near cutoff - collector voltage is close to the positive rail
Q2 - linear region - collector voltage is somewhere in the middle
Q3 - deep saturation - collector voltage is less than the base voltage

This is how it should be. If the collector voltage is too low, then the transistor's hFE is too high and vice versa. This is NOT a plug & play fuzz. More of a Goldilocks thing. You have to hand-select the transistors.

No idea…that or the TC-1 was feeling lazy…

 

[Chuck D. Bones]

LoL. Maybe you plugged all three in at once? Some folks are like that.