Debugging General Guitar Gadgets Fuzz Face Boutique Late 60s

Started by egosub2, February 07, 2015, 06:06:46 PM

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egosub2

I'm wondering if anyone can help with a build that's mystifying me. I bought three Fuzz Face Boutique Late 60s kits from General Guitar Gadgets, and I've built two so far, and have run into the same issue with both builds. Bypass works. The pedal turns on, LED lights up, but ... no fuzz, just a drop in volume and treble frequencies. The audio examples below were recorded directly into Reaper with no other effects applied and all pots at max.

Schematic: http://www.generalguitargadgets.com/pdf/ggg_ff5_sc_b69.pdf
Layout: http://www.generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf
General Instructions: http://www.generalguitargadgets.com/pdf/ggg_ff5_instruct.pdf

Build 1

In my first build, I did only the standard parts, omitting R1, R12, C6, and D3, as shown in the layout. I used the Si PNP transistors included in the kit, in the expectation of getting Ge transistors once it was working.
Images: http://imgur.com/a/3Ve81
Audio: https://soundcloud.com/langermax/build-1-audio/s-uKjoD

Measured voltages at the transistors on a battery giving 9.2 V as follows:

Q1
C = 4.3
B = 4.7
E = 0

Q2
C= 6.0
B= 5.3
E= 1.4

Build 2

In the second build, I included C6 and D3 and omitted R1 and R12. Again, I used the Si PNP transistors included in the kit.
Images: http://imgur.com/a/KNlpb
Audio: https://soundcloud.com/langermax/build-2-audio/s-fg9In

Measured voltages at the transistors on a battery giving 9.2 V as follows:

Q1
C = 5.0
B = 4.3
E = 0

Q2
C= 5.7
B= 5.0
E= 1.4

Conclusions

The circuit is working. In build 2 I've traced the whole thing from input to output and it's okay. The voltages obviously don't match the GGG instructions, although the vague statement on page five "This is also the NPN version" is confusing. Do I just need to get Ge transistors now that the circuit is verified? I would appreciate any help or whatever. Thanks for looking.

Your pal,

Doug

PRR

>Q1
>C = 4.3
>B = 4.7
>E = 0
>
>Q2
>C= 6.0
>B= 5.3
>E= 1.4


Q1c has to be the same as Q2b (they are directly connected).

The "b" pins should be 0.1V-0.6V away from the "e" pins; not ~~5V away.

Either you have four blown transistors, or your battery is backward. Are these voltages Positive or Negative of Ground when the black meter lead is on ground?

A backward battery, in this circuit, would make forward bias backward bias, the 0.1V-0.6V way-wrong and the wrong way.

With Si parts, and the battery polarity correct for the transistor polarity, it should "work", though some diddles of R5T will be needed to get Q2 C about half-voltage.
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egosub2

Voltage values should have been negative. They were measured with negative lead clipped to chassis ground.

egosub2

Well, reversing the polarity of the battery seems to have worked. No LED, but I'm guessing I just need to flip that around as well.

I'm mystified, since I followed the layout for the thing perfectly, but joy is by its nature a much stronger feeling than confusion, so that's well in the background.

THANK YOU THANK YOU THANK YOU

egosub2

Summary of my experiences for the benefit of anyone who Googles the General Guitar Gadgets Boutique Late 60's Fuzz Face:

Battery polarity seems to need to be reversed from what is shown in the Version 2011December08 layout. Reversing battery polarity and the LED in the layout results in a working pedal.

HOWEVER:

Doing this will smoke the optional diode, if you've added the optional D3/C6 power filter/reverse voltage protection. Omit these optional components and you have a working build.