Hi everyone!
I'm back once again, this time building a FTM-clone. But I am not satisfied with the amount of fuzz, it is too soft sounding and also very low volume-vise.
All of the transistors (2N3904) and are placed in the right way, same goes for the diodes (1N914). The voltages read extremely high at all the transistors, why?... It beats me!! I tried to wire both Q1, 2 and 4 emitter straight to the ground and THEN I got bit more gain but still not satisfying enough, the octave did not work in that mode either.
The octave works fine otherwise and I have noticed that the volume and gain increases when it is engaged.
I followed this layout:
(http://fuzzcentral.ssguitar.com/pcbs/foxxlayout.gif)
I connected the pots, switches and leds like this: http://www.generalguitargadgets.com/pdf/ggg_ftm_lo_2fsw.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a
(http://www.generalguitargadgets.com/pdf/ggg_ftm_lo_2fsw.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a)
Octave off:
Q1:
C 3.6
B 4.4 !!!
E 3.2
Q2:
C 3.8
B 3.7
E 3.1
Q3:
C 4.4 !!!
B 0.7
E 4.2 !!!
Q4:
C 2.1
B 0.6
E 1.4
Octave on:
Q1:
C 3.8
B 4.4
E 3.2
Q2:
C 3.9
B 3.7
E 3.1
Q3:
C 4.4
B 0.7
E 4.2
Q4:
C 2.1
B 0.6
E 1.4
one thingy I forgot to add, I used a 0.047uF instead of a 0.05uF cap in the "tone area".
Those 2 PCB's are different, therefore its likely there could be minor changes in how they are wired up. In fact, there is a major difference in one of the pots, might be the problem. Also, the ggg vol pot appears to be missing a ground wire.
Yes I noticed that too, so I added a ground wire from the output pot earlier.
When I dial the sustain pot to a little less the "max/full" I get a total signal dropout, must be something funky in that particular part.
Thats what I was trying to point you towards, the sustain pot is wired different on the 2 PCB's, the ggg wiring will completely stuff it up on the board you are using, check the wiring to sustain pot 1, 2 and 3, they are different.
Edit: there is some info on Bill Lawrence's drawing that tell you which wires go where. Compare that with ggg and you will see the problem. ;)
Yep! That is right!
By the way, I DID put the transistors backwards! *Face palm x2* Now it is working perfectly, a bit low volume but that can be fixed with a little biasing I guess.
Edit: I replaced the 1k5 at Q4 emitter and added a 270Ω instead and now... it is loud.
Quote from: stonerbox on March 24, 2012, 10:46:44 AM
By the way, I DID put the transistors backwards! *Face palm x2* Now it is working perfectly, a bit low volume but that can be fixed with a little biasing I guess.
Yep...by your voltages, you could see something was wired wrong before...here's the voltages of a working unit from ggg...note Q2-4 C all > 7v
Q1 Collector 2.2
Base 0.73
Emitter 0.16
Q2 Collector 7.5
Base 2.2
Emitter 1.6
Q3 Collector 7.28
Base 0.78
Emitter 0.21
Q4 Collector 7.63
Emitter 0.84
Base 0.26
Hello,
The FoXX Tone Machine PCB sold by GGG is fine. It's the basis of my DIY one, with a "more" selector added to increase gain and some light mods :
- switchable emitter decoupling 10uF cap on the 1st stage ("more" switch).
- 1st stage Q is a 2N5088 (Hfe ib10µA = 400) instead of a 2N3904 (Hfe ib10µA = 135).
- FUZZ and VOLUME pots are LOG instead of LIN.
(http://img4.hostingpics.net/pics/404123IMG4946JPG.jpg)
An "awful sounding" pedal... built for the fun... And there's fun in it, indeed !!!
A+!
Quote from: LucifersTrip on March 24, 2012, 08:54:39 PM
Quote from: stonerbox on March 24, 2012, 10:46:44 AM
By the way, I DID put the transistors backwards! *Face palm x2* Now it is working perfectly, a bit low volume but that can be fixed with a little biasing I guess.
Yep...by your voltages, you could see something was wired wrong before...here's the voltages of a working unit from ggg...note Q2-4 C all > 7v
Q1 Collector 2.2
Base 0.73
Emitter 0.16
Q2 Collector 7.5
Base 2.2
Emitter 1.6
Q3 Collector 7.28
Base 0.78
Emitter 0.21
Q4 Collector 7.63
Emitter 0.84
Base 0.26
Yeah, the voltages where kinda messy. I can't believe that I didn't double check the transistor pin-out earlier.
Quote from: tubelectron on March 25, 2012, 07:06:08 AM
Hello,
The FoXX Tone Machine PCB sold by GGG is fine. It's the basis of my DIY one, with a "more" selector added to increase gain and some light mods :
- switchable emitter decoupling 10uF cap on the 1st stage ("more" switch).
- 1st stage Q is a 2N5088 (Hfe ib10µA = 400) instead of a 2N3904 (Hfe ib10µA = 135).
- FUZZ and VOLUME pots are LOG instead of LIN.
An "awful sounding" pedal... built for the fun... And there's fun in it, indeed !!!
A+!
With the octave engaged it is pretty wild and the highs tend to be a little too harsh, at least for my taste, both with and without octave. Kinda off topic but right now I'm trying to tame this one a bit, achieving less highs and more mid and bass.