#1
Hi, everyone.

I made a clone Fuzz Face but am having 3 problems:

1. 3DPT switch makes a big pop sound when switched.
2. Volume comes out from the effect is very very low even at the max level of its pot(500k).
3. Level (volume) pot makes laud crackling sound when turned either directions.

I followed the schematic and board layout in the web link below.

http://gaussmarkov.net/wordpress/tools/software/eagle/eagle/

Except I replaced R3 to 1k, R4 to 18k and Gain pot to 2k (Jimi mod according to GEO).

I will be grateful if anyone can help me to solve the problems.
Thank you
#2
1) Pulldown resistor. 1M resistor from the positive lead of the 2.2uf capacitor to ground. That should help.

2) Bypass the pot. Run a straight wire from the .01uf capacitor to the hot connector of the output jack. If this works, then you can assume that 2 and 3 are due to pot failure as opposed to a circuit problem.

Curiosity question: silicon or germanium?
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#3
Thank you for the reply. Mine uses Germaniam AC128.

I like your username!
Could I clarify your comments below. (I am a quite beginner for these things)

"Pulldown resistor. 1M resistor from the positive lead of the 2.2uf capacitor to ground."

2.2uf cap positive lead is connected to Input. So what do i need to do please?

Sorry to be so novice.

I'm going to do your second suggestion straight away and will let you know the result.

Regards
#4
Ah so does mine.

Sure. You need to take a 1M ohm resistor and solder it from the positive lead of that capacitor, which is connected to the input, to the ground. So you take your resistor, and you solder it to the positive lead of the capacitor, and then you solder the other side of it to a ground connection. Thats it.
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#5
Your issue lies in your parts substitution.

R4 is critical in biasing the second stage properly. I would just replace the resistor with a 50K trimpot. Find the perfect spot and set it there, your pedal will then work fine.

Also crackling controls suggest DC is leaking into the signal path. Check your coupling caps.
#6
Hi,

I did bypass the level pot but the volume problem is the same. I also noted incidentally that the volume problem is same when the effect is not powered. I pluged it before connecting the battery and the bypass volume level is much higher than the volume through unpowered device.

Does this give you any other clue please?

I will do the resistor thing on another day after getting 1M resistor.

Regards
#7
No offense but I told you where your problem lies. Just fix that one little issue and your set, why fix popping and other lame sh it when the pedal sounds crappy and has no output?

If you get voltages on that second transistor (Q2) we could confirm that it is mis biased. Sounds like it's biased near cutoff.

Germanium transistors are a pain to deal with but they sound great. I always make sure I have some way I can bias them. Its a bit finicky but you'll get it.

Some other things just quickly to confirm...
You wired it as positive ground?
Transistor orientation correct?
Last edited by kurtlives91 at Jan 4, 2009,
#8
Hi, kurtlives91

thank you for your reply. The original FF layout use 8.2k for R4. Is 50k trimpot ok to replace (higher than the current 18k)?

How to check the coupling caps (you mean 0.01uf one?) for a leak?

Sorry to be so novice for these questions.

I appreciate your time for replying to me very much.

Regards
#9
Now that you know that the volume pot isn't the problem, just get a 25k/50k trimpot and dial in the bias voltage until it sounds good.
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#10
Thank you. I will do the remedy in a few days time and will report back.

I am going to back to see TV for play offs...

Best regards
#11
Hi, guys.

Thank you for your time to reply to me. Just a little clarifications. There is output (although very low). When I turned the amp's volume up, then it comes out very warm nice fuzz sound comes out. I look forward to reporting back to you guys after fixing the volume soon.

Best regards
#12
Are germanium transistors are not created equal...they dont all bias up the same way. Sticking one standard resistor value (8K2) is not a good idea.

Thats why the old FFs were real hit or miss (among other things).
#13
Hi, guys

I did changed 0.01 Cap and installed trimpot in place of R4. First did not change anything. And I tried change R3 for a lower value which resulted any improvements. Then I repleced back R3 to 1k......... Voila! great fuzz comes out now.

I still don't know what was wrong before. But thank you for the trimpot idea, it's great as I now can fine tune the amount of fuzz. My G-transistors are purchased from Germany where they handpicks a matching pair for a certain gain range. Now with trimpot, they are great. I still need to fix a poping bypass switch.

Thank you all again for your time to reply to me.

P.S. My wife started getting noisy as I added another pedal to the existing busy board and I told her the next project is to build Octavia...
#15
Hi,

With helps from you guys, my FF clone now sounds very good. But I found a little problem with power... When I plug it into my board power supply (8 DV 9v supply), the whole power supply shuts down. So I have to use a battery for my FF clone to keep power supply for other pedals. Is it because the FF is positive ground? I correctly wired DC socke to be center negative...
#16
Fuzzes sound better with a non-alkaline battery anyways. I built one last year, and i use it all the time. I still havent changed the battery. Its a cheap dollar store type, so i'm paying $1 a year to power my pedal. I would honestly just leave the battery in there.
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#17
If your other pedals are - ground you CANNOT use the same supply (daisy chained) for the + ground pedal. It needs it's own sperate supply.

That being said yeah batteries do sound better.
#18
Thank you again, guys.

Good to know that nothing wrong with my pedal for power issue. I'm going certainly to use batteries for future.

Cheers.
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