taming DIY fuzzface

Shiny_Beast

Gold Supporting Member
Messages
10,235
So I just put together a basic FF clone (PNP) based on the original FF schematic as far as I can tell. I used GE trannys from smallbear, 102/132 hfe.

Still getting it together but the results are promising. Putting it in front of my plexi spec 50 watter just kills. Even with the supplied resistors though, I have to jack Q2s bias resistence up to 15k just to get it to close to 5 volts, I'm guessing it's because it's winter now and cool in the basement, but that's prob #1.

Problem #2, it or my amp blocks/farts out when I put my microvibe in front of it on. With the vibe and wah on (wah in front of vibe) it's unusable. Is this normal, what could I do to tame it, back off the bias dial? But I'm not even at the coveted 4.5 volts as a starting point.

I'm using 680r across the top and 120k feedback with the standard 33k on Q1 collector.

Any know how available from FF experts?

thanks
Doug
 

cj_wattage

Member
Messages
6,678
This is kind of a heavy topic for a non-DIY forum. I'd suggest reposting this at DIYstopmboxes or BYOC or take a stab at the forum in my signature below. :)
 

Shiny_Beast

Gold Supporting Member
Messages
10,235
That's what came with the smallbear trannys. I'm a new fuzz user, so some of this I think is just typical fuzz stuff, like fuzzes don't always play well with other pedals.

It's starting to bias down to under 5 volts now, but I thiunk that's because the battery is dieing lol.


It sounds righteous in front of my plexi spec amp on 6+.
 

yeahyeahyeah

Silver Supporting Member
Messages
1,121
You should try to bias it at half of the supply voltage...not always exactly 4.5 volts.

What you are hearing with other pedals on in front of the fuzz face is just the nature of the beast, it usually sounds "best" first in the chain where it can load down your pickups.
 

basicaudio

Member
Messages
1,391
The smallbear resistors should be the biasing resistors fro the collectors.
The 470R (etc) value sets the output of the circuit as well as part ot the bias. Making it bigger will give you more output and you'll need to adjust the
bias with the trimmer (assuming your using one on Q2).
4.5v isn't the golden rule, it's just a starting place. There are a range of
"good"sounding collector voltages.

When you say blocking you mean that it's just too bassy etc correct?
Try a smaller input cap or even a variable cap with a 100K pot and a small/big cap combo a la Joe Gagan's easy face which you can find at GGG.
This will let you dial in the bass amount and really clean up a FF.

John
 

Shiny_Beast

Gold Supporting Member
Messages
10,235
He included all 4 resistors, 33l, 680 for the 470, 120 for the 100 and 10k for the 8.2

By blocking, I mean the note get's so loud that it cuts out completely. It does seem to relate to bass more than treble.
 




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