Help troubleshooting zvex fuzz factory clone

[guskenny83]

Hi,

I have built the zvex fuzz factory clone from madbeanpedals.com available here:

http://www.madbeanpedals.com/projects/Zombii/docs/Zombii_ver.5.pdf

and i am having trouble getting it to work

when the battery is connected and switch on, the LED will light up, but no sound is coming through at all.. with the switch off, it bypasses the pedal and the sound works fine, so i know its not the switch or the jacks

i followed the instructions available here: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

I was unable to get any germanium transistors, so i got some silicon replacements that were suggested somewhere on this site (i cant remember where sorry as it was a couple of weeks ago) - I cant remember the exact part numbers either because i lost the piece of paper i had them written down on, but the transistors themselves have "CEN 2N5 485" written on them if that helps

here are the results of the multimeter readings from the battery, all transistors, diodes and electrolytic capacitors

BATT:
V = 9.42 V

D1:
A = 9.42 V
K = 0 V

LED:
A = 9.42 V
K = 0 V

Q1: 2N 3904 029
C = 1.64 V
B = 0.66 V
E = 0 V

Q2: CEN 2N5 485
C = 1.52 V
B = 8.06 V
E = 9.43 V

Q3: CEN 2N5 485
C = 0 V
B = 1.52 V
E = 8.09 V

C1
A = 0.66 V
K = -0.23 V

C3
A = 9.42 V
K = 8.71 V

C4
A = 0 V
K = 0 V

C5
A = 9.42V
K = 0 V

Any help as to what might be wrong would be greatly appreciated. If there is any more information that i have not provided that would be helpful, please let me know

cheers

[induction]

2N5485 is an N-channel jfet. You need one NPN BJT and two PNP BJT's.

[Elijah-Baley]

Oh... you got a valid answer while I was writing. I post it anyway.

Hello and welcome. It is your first post here, so I want to ask you: It is you first pedal building?

About the voltage I can't help you, sorry. But theproblem could be some: I don't know your silicon transistors, so you gonna search the datasheet and compare the pinout with the stock transistor. We are taling about of PNP transistors, right?

(AC128 for fuzz factory are becoming hard to find, but not impossible. Did you try search on the web? On ebay there's a sort of a kit for the Fuzz Factory, maybe. Probably you will get a right and better sound with germanium transistors).

Another problem could be the wiring. Could you link us the wiring that you are using?

Furher, is a good method to test the circuit without footswitch and led. Just for see if the problem is in the circuit. Meanwhile, check (again) the value of the resistor and capacitar and their orientation, and the contacts of the wire on the board, pots, switch, etc.

[1878]

http://www.banzaimusic.com/Transistors-matched-selected/

I would seriously consider buying a couple of ac128's from the above link. I did & I can't tell the difference between my clone & a friends original unit. I think you need hfe 90 for Q2 & hfe 120 for Q3. That is from memory though, so I'd check !!

[Elijah-Baley]

I got a couple from Musikding.de, but now they have just some ac128 (also ac121) very low hfe.
Banzai could be a good alternative for european like me.

Those of mine are: AC128 - hFE=80-90 and AC128 - hFE=100-110. In the end I took these, you know, after a general research on the web. Someone use lower, someone else higher.
Unfortunatelly, I didn't finish my fuzz factory, (missing components). If fate allows me, I'll complete it next month.

Give us your news, man.

[Kipper4]

I just opened up my version 1.1
heres my voltages
Q1 2n3904
C 0.6
B 0.6
E 0
Q2AC128
C 9
B 8.9
E 6.5
Q3 AC128
C 6.6
B 6.5
E 6.6