What's your favorite Fuzz Face build?

phi1

Well-known member
For Ge fuzz face builds these days, be aware it can be a challenge to source Ge transistors in the correct Hfe range, or you may want to buy a lot and test the Hfe yourself. Smallbear used to sell pre-tested kits for FF, not sure if there’s anywhere doing that sort of thing currently.
 

jwyles90

Well-known member
For Ge fuzz face builds these days, be aware it can be a challenge to source Ge transistors in the correct Hfe range, or you may want to buy a lot and test the Hfe yourself. Smallbear used to sell pre-tested kits for FF, not sure if there’s anywhere doing that sort of thing currently.
Good lookin out! I've had some decent success with those kinds of parts from Guitarpcb.com, they sell pre-matched sets for fuzz face kits as well.
 

Coda

Well-known member
I would suggest the Sandspur PCB, though with the FF input cap. You’d also probably need a cap across Q2. The reason: the Ge FF sound (the one everyone goes crazy over) requires an amp that’s already cooking…like a loud Marshall, etc. Ge FF into a very clean amp is, well…underwhelming. Si FF, however, it’s excellent. You can socket the transistors and swap out different things…BC108 (the standard), BC109C (my favorite), BC549C (the same things as 109C, but I find that they sound a bit thicker, though not as full), BC107, and so on and so on. Each set will sound slightly different.
 

jwyles90

Well-known member
I would suggest the Sandspur PCB, though with the FF input cap. You’d also probably need a cap across Q2. The reason: the Ge FF sound (the one everyone goes crazy over) requires an amp that’s already cooking…like a loud Marshall, etc. Ge FF into a very clean amp is, well…underwhelming. Si FF, however, it’s excellent. You can socket the transistors and swap out different things…BC108 (the standard), BC109C (my favorite), BC549C (the same things as 109C, but I find that they sound a bit thicker, though not as full), BC107, and so on and so on. Each set will sound slightly different.
Yea that’s a good point about how germanium reacts to the amp as well. It’s been such a long time since I’ve played into a solid state amp that I have a hard time gauging how something will sound on it. Silicon seems like a safe bet though
 

Coda

Well-known member
Yea that’s a good point about how germanium reacts to the amp as well. It’s been such a long time since I’ve played into a solid state amp that I have a hard time gauging how something will sound on it. Silicon seems like a safe bet though

I personally like the sound of a Ge FF and a clean amp…but it doesn’t sound like Hendrix…
 

Big Monk

Well-known member
I’ve come to really love the Fuzz Face, when for years I would forego it in favor of the MK II/Supa.

It’s such a simple circuit but has a varied number of “levers” to pull to tweak the tone.

I’ve been trying in my mind to approach it in chunks based on what I need:

1.) Cleanup Ability
2.) Overall Gain
3.) Overall Brightness
4.) Noise Reduction

There are a number of different combinations you can use to achieve any mixture of those 4 goals.

Germanium, Low Gain Silicon, High Gain Silicon, Hybrid, etc.
 

cdwillis

Well-known member
I haven't played a bunch of Fuzz Faces, personally. I built a Meathead clone, then a clone of the Dr Tony Balls Colorsound fuzz clone. They both sounded great. I've got a modified version of that type of circuit on my breadboard that I think I've tweaked/finished so I need to build a vero version. It's somewhere between the colorsound clones and a silicon fuzz face. I left the fuzz maxed out with the 1k resistor rather than have a fuzz control. The bias knob can take you from an overdriven type sound to a spitty gated fuzz. The input cap blend is pretty tight set to the 4.7nf cap, almost like a fatter treble booster, but blending towards the 1uf cap make it sound fatter and doomy. Cleans up pretty good with the guitar volume too.
 

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jwyles90

Well-known member
Man you all are giving me some great options! For my friend’s build I think I’m going with the Sandspur, but this thread has made me look more into veroboard builds and I definitely want to give a couple of those a shot soon for myself.
 

andare

Well-known member
I haven't played a bunch of Fuzz Faces, personally. I built a Meathead clone, then a clone of the Dr Tony Balls Colorsound fuzz clone. They both sounded great. I've got a modified version of that type of circuit on my breadboard that I think I've tweaked/finished so I need to build a vero version. It's somewhere between the colorsound clones and a silicon fuzz face. I left the fuzz maxed out with the 1k resistor rather than have a fuzz control. The bias knob can take you from an overdriven type sound to a spitty gated fuzz. The input cap blend is pretty tight set to the 4.7nf cap, almost like a fatter treble booster, but blending towards the 1uf cap make it sound fatter and doomy. Cleans up pretty good with the guitar volume too.
Thanks for adding your schematic.

I've been breadboarding fuzzes for a few weeks and I'm trying to learn some basics.

I understand most of the mods you've made but I have a couple of questions if you don't mind.

What's the function of the 100r in the power filtering section? Isn't the 47uF cap enough?

The small cap to ground after the pulldown resistor is there to reduce hiss and radio signals right?

About the values you chose for the small caps on the transistors. I know those smooth out the sound and must be small but are the values selected empirically or is there a logic, Q2 has a smaller cap.

And finally why a 100k pot for volume? I still don't understand how to select pot values.

Sorry for the barrage of questions. You can tell me to just Google it and I'll take it :)
 

jwyles90

Well-known member

rmfx

Active member
Oooh I got some favorite mods!
-B500k for volume and C1k for fuzz. Always found the stock pots bunched the whole useable range in the last bit of rotation. These tapers gave me a LOT more useable room and fine-tweakability.
-Bump the 330-470R resistor up to 1k for a bit more volume.
-External 10k bias trim pot! I think the fuzz face sounds GREAT overbiased. Takes on more of an overdrivey characteristic. Of course, starving Q2 also sounds pretty cool.
-Lower the input cap to get rid of some of the tubbiness.
-Some fuzz faces gave me buzz when my guitar's volume knob was at 0, and the noise decreased as I turn up the volume. Throwing a resistor in series between the input and first cap helped this and didn't seem to effect the stock sound of the fuzz face too much to my ears. Can't remember the value but I think somewhere between 100-470R sounds correct. I tried a bunch of values and went with the lowest value I could while getting the noise floor down to my liking with my guitar's volume at 0.
 

Feral Feline

Well-known member
Has anybody named their build "Fuzz Facebook"?

Edit: there-their now, it's okay to have the odd typo
 
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cdwillis

Well-known member
Thanks for adding your schematic.

I've been breadboarding fuzzes for a few weeks and I'm trying to learn some basics.

I understand most of the mods you've made but I have a couple of questions if you don't mind.

What's the function of the 100r in the power filtering section? Isn't the 47uF cap enough?

The small cap to ground after the pulldown resistor is there to reduce hiss and radio signals right?

About the values you chose for the small caps on the transistors. I know those smooth out the sound and must be small but are the values selected empirically or is there a logic, Q2 has a smaller cap.

And finally why a 100k pot for volume? I still don't understand how to select pot values.

Sorry for the barrage of questions. You can tell me to just Google it and I'll take it :)

The 100 ohm resistor is there to help quiet down any power supply ripples along with the 47uf cap. You could remove it and probably not notice a difference. Or you could bump it up to 220 ohm or 470 ohm and get a little less voltage to the circuit so you have more of that low battery type of sound people dig with fuzz faces.

As far as the miller caps go, this started off as a Colorsound fuzz on the breadboard, which used a 220pf miller cap on q1 according to one schematic and no miller cap on q2. That may have been the reissue version or something. There's a bunch of one knob fuzzes that use the same topology with tweaked values. I've built a clone of the DAM Meathead and it had a 470pf miller cap on q1 along with a 47pf cap on q2. I thought it had a bit of a mid notched sound at times so I played around with the miller cap values to get something that smoothed out the silicon transistors inherent qualities without taking away too much sparkle. I couldn't tell you what equation to use to determine what it's frequency response is. I just went by ear.

The 100pf to ground on the input just cuts out radio signals. My house has old wiring and I live down the street from a radio station so when I breadboard fuzzes, specifically these fuzz face or tonebender mk1.5 type circuits, I always pick up radio signals. The cap helps cut them out so I can turn my guitar volume down without hearing country music lol.

If you have a circuit that has a big volume output, using a logarithmic pot for the output volume works well because the taper shifts the loudest portion further clockwise on the knob. In a lower output circuit you can use a linear pot which has more volume earlier in the sweep. That will make it seem like the circuit is louder than it is because noon on the volume pot will be louder, you just won't have a tone of volume boost further clockwise like you would with a logarithmic pot. With the bias pot on here you lose a little volume once you get into that spitty velcro fuzz portion of the pot so I wanted to use a linear pot to make it seem a little louder. On the other hand turning the bias pot the other way makes it pretty damn loud.

I went with 100k for the volume pot because it's a common part really and I'm also using 100k for the input cap blend, so it's less unique parts to stock. I changed the output cap to to a larger one than the old fuzzes have so it would have a full bass output all the way through the volume pretty much. The output cap forms a high pass filter with the volume pot so a smaller cap will cut some bass out at lower volume output. You can use a filter calculator to determine the frequency response (http://www.muzique.com/schem/filter.htm), but I'm not totally sure how much the resistance in the front of the pot when using it as a voltage divider effects the response.
 

andare

Well-known member
The 100 ohm resistor is there to help quiet down any power supply ripples along with the 47uf cap. You could remove it and probably not notice a difference. Or you could bump it up to 220 ohm or 470 ohm and get a little less voltage to the circuit so you have more of that low battery type of sound people dig with fuzz faces.

As far as the miller caps go, this started off as a Colorsound fuzz on the breadboard, which used a 220pf miller cap on q1 according to one schematic and no miller cap on q2. That may have been the reissue version or something. There's a bunch of one knob fuzzes that use the same topology with tweaked values. I've built a clone of the DAM Meathead and it had a 470pf miller cap on q1 along with a 47pf cap on q2. I thought it had a bit of a mid notched sound at times so I played around with the miller cap values to get something that smoothed out the silicon transistors inherent qualities without taking away too much sparkle. I couldn't tell you what equation to use to determine what it's frequency response is. I just went by ear.

The 100pf to ground on the input just cuts out radio signals. My house has old wiring and I live down the street from a radio station so when I breadboard fuzzes, specifically these fuzz face or tonebender mk1.5 type circuits, I always pick up radio signals. The cap helps cut them out so I can turn my guitar volume down without hearing country music lol.

If you have a circuit that has a big volume output, using a logarithmic pot for the output volume works well because the taper shifts the loudest portion further clockwise on the knob. In a lower output circuit you can use a linear pot which has more volume earlier in the sweep. That will make it seem like the circuit is louder than it is because noon on the volume pot will be louder, you just won't have a tone of volume boost further clockwise like you would with a logarithmic pot. With the bias pot on here you lose a little volume once you get into that spitty velcro fuzz portion of the pot so I wanted to use a linear pot to make it seem a little louder. On the other hand turning the bias pot the other way makes it pretty damn loud.

I went with 100k for the volume pot because it's a common part really and I'm also using 100k for the input cap blend, so it's less unique parts to stock. I changed the output cap to to a larger one than the old fuzzes have so it would have a full bass output all the way through the volume pretty much. The output cap forms a high pass filter with the volume pot so a smaller cap will cut some bass out at lower volume output. You can use a filter calculator to determine the frequency response (http://www.muzique.com/schem/filter.htm), but I'm not totally sure how much the resistance in the front of the pot when using it as a voltage divider effects the response.
Thank you for the thorough answer!
 

fredeharley5

New member
I dusted off the S/T Stone Roses album and b-sides and now I have a raging case of Fuzz Face GAS.
Most folks believe this is a silicon model (possibly a Crest Audio-built one with BC109C transistors). I've checked out some demos and it definitely sounds like it. Loud and proud and it seems like it's even a bit brighter with the guitar volume rolled down. Anything in that general tonal ballpark would be fine though.

I'm primarily a single-coil player, use 1x12 Fenderesque amps, and play indie rock and Americana-type stuff. Not looking for a doomy variant in other words.
 
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