Yet, Another Fuzz Face Mod...Maybe

[dstrats]

Hi all,



This is another Fuzz Face I own. It is the newest Dunlop version of a Hendrix FF. It's loaded with BC108s'. It's not the greatest fuzz tone unfortunately. It's very sterile and not that fuzzy. After finishing the mod of my other FF I thought I'd be able to place a trim-pot to add a lil more hair to the over-all fuzz sound. But, I noticed it has "precision" resistors installed. I know these are at 1%. I thought, I'm just assuming now, that maybe that's why it's so sterile? My other two FF employs 5%, and they have fuzz to spare. Again, I'm not sure if indeed there are differences in the actual sound between 1% and 5%, but that's one of the differences between the other FF I have.

I started to wonder if perhaps I can replace the 1% precision with carbon comp 5% resistors. I'm unsure if it would would work being that I don't know how precision resistors differ from carbon, or regular resistors. The resistor above the .1uf cap is 3.16K, where on the FF I worked on, and in my Crest FF, there is a 8.2K. So, I don't know if I could actually change the resistors without harming something or just not getting any signal at all.

So, besides installing a trim-pot on the 3.16K, is there a way to get this fuzz less sterile sounding? And, is it possible to put in different resistors with "vintage correct" values without harming anything?

Thanks in advance! Look forward to some replies. 

[jayp5150]

You have to keep in mind that the 'vintage correct' values will vary dependent on the transistors. Your best bet is to change resistor values as needed to get all your voltages to a good baseline, and then tweak by ear from there.

The only difference between the 1% and 5% resistors is accuracy. There won't be some magical tonal difference between the two, only more consistency, but if you check all your parts with your DMM at assembly, that becomes less relevant, IMO.

[dstrats]

Hi "jayp5150",

I appreciate the reply. Thanks for clarifying that there is no magical difference 'tween resistor accuracy. I know it was crazy to even assume that but I just took a chance. 

Can you tell me how I'd go about using a DMM? I do own one, I just don't know what to touch the +/- leads to. I know that sounds weird but I'm very new to all this but really wanna learn. How do I make sure I get, "all my voltages to a good baseline"? Is it by changing one piece at a time and then checking with a DMM?

BTW, why would this pedal sound so weak in the actual fuzz tone? Is it because it's not properly biased? Is it because the "voltage" isn't right? How do I check what the transistors need in the way of resistor value? What does it mean (if anything) that it appears that the middle lead of the transistor "B" is crossed over and that "C" is in the middle? My other two FFs' (going by the FF board in this thread) "C" is in the left, "B" is in the middle, and "E" is on the right.

Thanks again for the reply. I look forward to any more help with this FF. 

[jayp5150]

Read up on this.

http://www.geofex.com/article_folders/fuzzface/fffram.htm

There's a wealth of info there and on this forum regarding the fuzz face.

To take the voltages, though, you'll set your DMM to the 20v setting, place the black lead to ground, and check each leg of both transistors with the red lead. If it's a positive ground, these will be negative voltages.

Aside from that search 'fuzz face voltages' or 'fuzz face bias' here and just start digging up old threads.

[zombiwoof]

If you bought that pedal new, I would send it back to Dunlop for warranty work, the Hendrix FF has been well-received, and should have plenty of fuzz to spare.  Are you putting any other pedals in front of it, or is it like that by itself?.  Fuzz Faces don't like any buffered pedals in front of them.

Al

[jayp5150]

^ a very valid point. I forget the obvious stuff sometimes lol.

[Electric Warrior]

doesn't this one have trim pots on the back of the board?

[dstrats]

Hi all,

So, I've owned this pedal for about, maybe, two years. Not sure if I can send it back this point. And no, this FF does not have a trim-pot installed. Nothing is in front of the FF usually... perhaps a true-bypass wah occasionally but usually the FF is alone and this one sounds way sterile. Oh, a new battery was placed in too so it's not a lack of power. 

"jayp5150", thanks for instructing me on how to use the DMM. I truly appreciate that. I will look around the forum to find stuff thanks. 

[tcobretti]

What I would do it sell it and get your money out of it.

But, if that isn't an option, I'd put a trimpot in the standard location on the collector of Q2 and tweak.  If that didn't work I'd put on on the collector of Q1.  If that didn't work I might try a 200k in place of the feedback resistor.

Then I'd give up, gut it, and put in an Axis Face.  In fact, this might be a good place to start - lower hfe transistors. 

But once again, you should just sell it and build one from scratch if that is what you plan to do.  It's gotta be worth $100 as it is.

[zombiwoof]

Actually, I believe that FF does have one or two trimpots, they are on the opposite side of the board as I recall, and are very small.  Maybe under a little sticker or something.  I remember reading about them, and some guys had trouble finding them (or it, I can't remember if it's one or two).  Supposedly bias trim.  Check the other side of the board.

Al

[dstrats]

Actually, I believe that FF does have one or two trimpots, they are on the opposite side of the board as I recall, and are very small.  Maybe under a little sticker or something.  I remember reading about them, and some guys had trouble finding them (or it, I can't remember if it's one or two).  Supposedly bias trim.  Check the other side of the board.

Al

Yep!

You are right Al. Two of 'em right underneath the resistors. Thanks. Now to dial it in correctly. After fiddling with it I made it sound "gated". I'll figure this thing out yet.

Thanks again guys! Take care!