Dunlop - Eric Johnson Signature Fuzz Face EJF1

beedotman · Post by **beedotman** » 06 Aug 2012, 07:53

^ It's not the way how I would do this, but should be pretty much ok.
hard to say, becouse tracks are hidden by components.

rosetta · Post by **rosetta** » 07 Aug 2012, 04:08

ok. PCB

harmaes · Post by **harmaes** » 27 Aug 2012, 10:47

I've been experimenting a lot with trannies in this circuit and so far I really love a lower gain one with 2x 2n2396, with a resistor of 4,7k to be able to bias the Q2C at 4,4-4,5 volts. Great warm sounding fuzz IMO. Try it out and lemme know if you like it.

I also combined a BC183C in Q2 (585 HFE) with anything around 300 HFE in Q1 (BC547-BC548-BC549B). Also with a 2n2222A in Q1 (HFE 200ish) it does sound great with 3v on Q2C.
And finally a fuzz with 2x BC109C with 3v on the Q2C has the most gain and is also nice.

Skreddy · Post by **Skreddy** » 28 Aug 2012, 04:23

Try piggybacking those transistors. Takes the sound to the next level.
Here's what my BC109 fuzz looks like (till I get a new layout made to accommodate all the extra crap on board)...

4.7k inline with a 5k pot for Q2's 9v to collector. Toggle switch adds in a 56k resistor inline with input for humbuckers. 470pf cap across the volume pot. 15pf "miller" cap on Q1. 10 ohms in-line with the 22uf fuzz cap. Nice Nichicon electrolytic caps (2.2uf input, 22uf fuzz). Output cap is a .068uf film type (instead of .01uf), because the volume pot is a B100K pot instead of C500K.

Q1 (x2) is ~250 Hfe BC109, Q1 (x2) is ~550 Hfe BC109C.

Everything else is classic, standard Fuzz Face, other than the LED (sounds and biases better without, but customers do not like if you leave it out, and since you're already adding a bias pot, no biggy).

harmaes · Post by **harmaes** » 29 Aug 2012, 14:55

Cool idea Marc! Will try that out, thanks for sharing!

harmaes · Post by **harmaes** » 29 Aug 2012, 19:51

I've tested the different fuzz faces I'm creating with a strat with single coils. I've just finished one which is close to the EJ design (BC550B and BC183C - biased to 3v). It's working great and is very sputtery/spongy.
I noticed when rolling back the volume of another guitar with a humbucker in the bridge that the fuzz started picking up noise like when it's wrongly biased. This does not happen with single coils. Can this be related to the 1uf input cap? Should I change that or add a resistor like mentioned by Skreddy for humbuckers?

EDIT: when Lowering the fuzz pot the problem disappears. It's most obvious when the fuzz is maxed out.

Thanks!

Skreddy · Post by **Skreddy** » 29 Aug 2012, 23:25

harmaes wrote:I've tested the different fuzz faces I'm creating with a strat with single coils. I've just finished one which is close to the EJ design (BC550B and BC183C - biased to 3v). It's working great and is very sputtery/spongy.
I noticed when rolling back the volume of another guitar with a humbucker in the bridge that the fuzz started picking up noise like when it's wrongly biased. This does not happen with single coils. Can this be related to the 1uf input cap? Should I change that or add a resistor like mentioned by Skreddy for humbuckers?

EDIT: when Lowering the fuzz pot the problem disappears. It's most obvious when the fuzz is maxed out.

Thanks!

The 10 ohm resistor (in series with the fuzz capacitor or else in between Q2's emitter and the fuzz cap/pot) is for that problem. Eliminates the possibility of turning the fuzz all the way up. Experiment with different values, with 100 ohms being as high as you'll probably ever need.

harmaes · Post by **harmaes** » 30 Aug 2012, 07:00

Skreddy wrote: The 10 ohm resistor (in series with the fuzz capacitor or else in between Q2's emitter and the fuzz cap/pot) is for that problem. Eliminates the possibility of turning the fuzz all the way up. Experiment with different values, with 100 ohms being as high as you'll probably ever need.

That's the 27R in the EJ FF probably. I can try different values there.
I'm always eager to know the reason behind this.

Is this because impedance/output, loading of humbuckers is different then single coils? Why did you use a 56k resistor with the input cap for humbuckers? Would really help to know what I'm trying to cure.

Oh BTW, I used a normal poly 1uf input cap instead of an elco. That shouldn't be a problem if I'm correct?

Skreddy · Post by **Skreddy** » 31 Aug 2012, 05:29

harmaes wrote:
Skreddy wrote: The 10 ohm resistor (in series with the fuzz capacitor or else in between Q2's emitter and the fuzz cap/pot) is for that problem. Eliminates the possibility of turning the fuzz all the way up. Experiment with different values, with 100 ohms being as high as you'll probably ever need.
That's the 27R in the EJ FF probably. I can try different values there.
I'm always eager to know the reason behind this. Is this because impedance/output, loading of humbuckers is different then single coils? Why did you use a 56k resistor with the input cap for humbuckers? Would really help to know what I'm trying to cure.

Oh BTW, I used a normal poly 1uf input cap instead of an elco. That shouldn't be a problem if I'm correct?

I don't know; some Fuzz Faces just oscillate with the fuzz up 100%, and that resistor acts as a high limit.

I settled on 56k 'cause it seems to be the right value on the input side for me to get the same fuzz tone from my SG as my Strat. Without a resistor up front, a humbucker will swamp the circuit and make it not sound like a Fuzz Face but a mis-biased Tone Bender. A poly 1uf would be quite bit, yeah? How does it sound?

harmaes · Post by **harmaes** » 31 Aug 2012, 07:51

Skreddy wrote: I don't know; some Fuzz Faces just oscillate with the fuzz up 100%, and that resistor acts as a high limit.

I settled on 56k 'cause it seems to be the right value on the input side for me to get the same fuzz tone from my SG as my Strat. Without a resistor up front, a humbucker will swamp the circuit and make it not sound like a Fuzz Face but a mis-biased Tone Bender. A poly 1uf would be quite bit, yeah? How does it sound?

The oscillation only happens with humbuckers with the fuzz up 100%. Will try some other guitars to see what happens. Otherwise I'll lower the fuzz a bit for humbuckers.

I'll try the 56k with a switch on the fuzz faces I created. What value input cap do you use it with? The resistor placed before the input cap?

Ive used and seen a 1uf poly cap in different circuits. It sounds good to me, allowing most frequencies to pass through.

Skreddy · Post by **Skreddy** » 31 Aug 2012, 21:51

harmaes wrote:
Skreddy wrote: I don't know; some Fuzz Faces just oscillate with the fuzz up 100%, and that resistor acts as a high limit.

I settled on 56k 'cause it seems to be the right value on the input side for me to get the same fuzz tone from my SG as my Strat. Without a resistor up front, a humbucker will swamp the circuit and make it not sound like a Fuzz Face but a mis-biased Tone Bender. A poly 1uf would be quite bit, yeah? How does it sound?
The oscillation only happens with humbuckers with the fuzz up 100%. Will try some other guitars to see what happens. Otherwise I'll lower the fuzz a bit for humbuckers.

I'll try the 56k with a switch on the fuzz faces I created. What value input cap do you use it with? The resistor placed before the input cap?

Ive used and seen a 1uf poly cap in different circuits. It sounds good to me, allowing most frequencies to pass through.

I'm using 2.2uf input like the classic stock circuit. Yeah; resistor goes in front (not that I think it matters a bunch; but if it does, then the possible (negligible) high-pass effect is probably a good thing for humbuckers anyway).

edge59 · Post by **edge59** » 02 Oct 2012, 02:51

Hi there, do you sell PCB's for the Fuzz Face? I love your comments! I played a Joe B. Fuzz face the other day, but it seemed to be somewhat lacking. I am interested in building one of these guys.
take care,
Ed

beedotman · Post by **beedotman** » 02 Oct 2012, 07:03

great pcb's for fuzz face type projects You can buy from madbean:
http://madbeanpedals.com/projects/Mangl ... angler.pdf

DrNomis · Post by **DrNomis** » 02 Oct 2012, 07:27

You can also buy the Mojo Fuzz Face PCB kit from Pigeon FX, you get all the Mojo style vintage parts plus a Brown Paxolin Etched PCB in the kit, here's a pic of the insides of my Germanium Fuzz Face build using the Mojo Fuzz Face kit I bought recently, the only components you need are the transistors, pots, footswitch, sockets, battery clip & holder, knobs, and enclosure:

beedotman · Post by **beedotman** » 02 Oct 2012, 10:54

DrNomis wrote:You can also buy the Mojo Fuzz Face PCB kit from Pigeon FX

okgb · Post by **okgb** » 02 Oct 2012, 13:33

Is there a summary of what parts make the EJ circuit different ? , not many parts so it can't be much ?

sinner · Post by **sinner** » 02 Oct 2012, 13:57

F

okgb wrote:Is there a summary of what parts make the EJ circuit different ? , not many parts so it can't be much ?

It's all in this tread - full schematic with transistor voltages

DrNomis · Post by **DrNomis** » 02 Oct 2012, 14:32

okgb wrote:Is there a summary of what parts make the EJ circuit different ? , not many parts so it can't be much ?

This whole thread was about dissecting and analyzing the Dunlop Eric Johnson Fuzz Face, so you should have a good read of all the posts, all the relevant info is here....

okgb · Post by **okgb** » 02 Oct 2012, 14:50

As with allot of the threads , sometimes are not conclusive between the opinions & debates
makes it a little harder getting the parts order together but I see some good info at the start , before
" refinements " begin ....................thanks

sinner · Post by **sinner** » 02 Oct 2012, 15:05

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Dunlop - Eric Johnson Signature Fuzz Face EJF1 [traced]