Gibson Maestro Fuzz Tone FZ-1A - Needs Help

[vintagekiki]

https://sites.google.com/a/davidmorrin.com/www/home/trouble/troubleeffects/maestro-fuzz-tone

http://diy.smallbearelec.com/Projects/FuzzE-One/FuzzE-One.htm

https://sites.google.com/a/davidmorrin.com/www/_/rsrc/1426694525959/home/trouble/troubleeffects/maestro-fuzz-tone/FZ-1B%20early.png

https://www.diystompboxes.com/smfforum/index.php?topic=98202.0

https://www.diystompboxes.com/smfforum/index.php?topic=94695.0

https://music-electronics-forum.com/forum/effectification/guitar-effects/50200-gibson-maestro-fuzz-tone-issues

1)
https://johannburkard.de/blog/music/effects/legendary-guitar-effects-maestro-fuzz-tone-fz-1-fz-1a-fz-1b.html
The Maestro Fuzz-Tone FZ-1, FZ-1A and FZ-1B
2)
https://www.thegearpage.net/board/index.php?threads/fz-1-vs-fz-1a-maestro-fuzzes-differences.1656644/

[misterc57]

R4 voltage makes sense. Should be closer to 1.4V It's given by battery voltage minus Q2 base-emitter voltage (very low for Germanium). You will need to lower the value of R4.
And Q3 will need a resistor between base and supply as well. Start with something like 1M.

Well I tried, and I tried, I got, Satisfaction! Pedal is working (no more splat) and in my opinion is nailing the Satisfaction sound.

After experimenting, I added the old 470K resistor (which was reading around 530K) between Q3 base and supply. This step alone had the largest influence. R4 was changed to a 330K which smoothed the sound a bit. At that point it sounds good so I did not try any other changes.

Thank you Helmholtz and all others for the help and education. MC

[Helmholtz]

Well I tried, and I tried, I got, Satisfaction! Pedal is working (no more splat) and in my opinion is nailing the Satisfaction sound.

After experimenting, I added the old 470K resistor (which was reading around 530K) between Q3 base and supply. This step alone had the largest influence. R4 was changed to a 330K which smoothed the sound a bit. At that point it sounds good so I did not try any other changes.

Thank you Helmholtz and all others for the help and education. MC

To help others: What are your Q2 and Q3 collector voltages now?

[misterc57]

All negative readings...

Q2 collector voltage varies from .78 to 1.52 depending on the position of the 50K "Attack" pot.
Q3 collector voltage varies from .88 to 1.05 depending on the position of the 50K "Attack" pot.

[Helmholtz]

All negative readings...

Q2 collector voltage varies from .78 to 1.52 depending on the position of the 50K "Attack" pot.
Q3 collector voltage varies from .88 to 1.05 depending on the position of the 50K "Attack" pot.

The attack control should not change the collector voltage of Q3. Seems you have a leaky C3.

[misterc57]

The attack control should not change the collector voltage of Q3. Seems you have a leaky C3.

Interesting. C3 is a newer radial cap. I will replace it and report back.

To test, can I clip a new one in parallel, or would the old one still leak?

Thank you

[Helmholtz]

Interesting. C3 is a newer radial cap. I will replace it and report back.

Observe correct polarity!

, or would the old one still leak?

Yes.


I would replace both C2 and C3 with 1µ polyester/Mylar film caps. Will last forever and polarity doesn't matter.

[vintagekiki]

Maestro Fuzztone from A to Z

US3213181_fuzztone1965.pdf

[misterc57]

I lifted one leg of C3 and clipped in a new 1u cap. C3 collector voltage stable. Clipped leg of old 1u back in to confirm problem. C3 collector voltage stable. Hmmm.

Soldered leg of old cap back in and C3 collector voltage remains stable across all settings of 50K Attack pot. So I do not know what was going on.

New readings.

Q2 collector voltage varies from .98 to 1.54 depending on the position of the 50K "Attack" pot.

Q3 collector voltage stable at 1.24 regardless of position of the 50K "Attack" pot.

[benjamo]

Hello:
Thanks for the collective wisdom here...I'm somewhat electrically illiterate but thought I'd take a chance with addressing a FZ!-B issue. It sounds great, like it should initially, but the sound does not decay naturally, i.e., it rings for a few moments, then is gone. Any suggestions?

[mozz]

Pretty sure the 1B is a totally different animal. Better off to start a new thread.