BJF - Folk Fuzz

StickMan · Post by **StickMan** » 02 Jan 2008, 22:37

Hey Bjorn!

I have a couple of questions about the Folk Fuzz.

I noticed that you moved the "Fuzz" control from the traditional spot on the emitter of Q2 to the input. So the "Fuzz" is essentially on full and the knob now works much the same as rolling back the volume on the guitar with an original FF. This makes sense to me.

Why did you rig it up the way you did, with a separate 1M resistor off the sweep to ground? Why not just connect the jack to lug 1 of the pot, log 3 to ground and the sweep to the input of the circuit?

Second question:

Why use two different types of MOSFETs for the clipping diodes. Why not use two the same, and simply flip one around so it clips in the other direction?

Thanks for your time. Like many others here, I appreciate the time you've taken to explain your approach to us on this board.

dave.

BJF · Post by **BJF** » 02 Jan 2008, 23:58

StickMan wrote:Hey Bjorn!

I have a couple of questions about the Folk Fuzz.

I noticed that you moved the "Fuzz" control from the traditional spot on the emitter of Q2 to the input. So the "Fuzz" is essentially on full and the knob now works much the same as rolling back the volume on the guitar with an original FF. This makes sense to me.

Why did you rig it up the way you did, with a separate 1M resistor off the sweep to ground? Why not just connect the jack to lug 1 of the pot, log 3 to ground and the sweep to the input of the circuit?

Second question:

Why use two different types of MOSFETs for the clipping diodes. Why not use two the same, and simply flip one around so it clips in the other direction?

Thanks for your time. Like many others here, I appreciate the time you've taken to explain your approach to us on this board.

dave.

Hi Dave,

Well as you can see in the circuit it has a voltage controlled input, by means of the resistor in series with the input. As this is varied it aslo affects the base response as it works as a filter as well and the 1M resistor works as a resistans multiplier actually just a part of damping at minimum fuzz so the pot appears to be twice as big.
This makes also minimum noise at minimum fuzz- this is explanied in the original article
..
This circuit does not run on maximum gain but has a a couple of feedback systems that makes the circuit stable using many different types of transistors and also feedback system to control excess noise.

The circuit is a basic application of a two stage transistor amplifier to get higher gain and higher input impedance than a single transistor.

Two different Mos fets?
Well as you can see in the original articles when using bipolar transistors the base to emitter doide is used since that junction is made to be progressive in tenths of the total forward voltage.

Of course you can use J-fets or Mos fets connected as diodes as well with slightly different results.

I have built very few but some of these using the transistor of the day in the true spirit of the Folk Fuzz- use what you can and what sounds good

Have fun
BJ

Whoismarykelly · Post by **Whoismarykelly** » 02 Jan 2008, 23:58

I believe he uses pots to alter the input impedance on several of his pedals.

BJF · Post by **BJF** » 03 Jan 2008, 00:02

Whoismarykelly wrote:I believe he uses pots to alter the input impedance on several of his pedals.

Hi,

Well atleast some;)this has a very interesting effect on pick ups aswell considering the high Z nature of guitar pick ups

have fun
BJ

StickMan · Post by **StickMan** » 03 Jan 2008, 03:24

Bjorn,

Thanks for the info. I wasn't able to find the original articles anywhere (at least not in English). The pot wiring makes sense now. I had actually popped a 1M pot at the front of an ROG Tantalus Project fuzz, wired as I had described, but I'll go back and change it to see how it works.

I still have one more question, on the Deluxe 3,5% schematic: Where does the 3 lug on the "Diskant" pot connect?

soulsonic · Post by **soulsonic** » 13 Jul 2008, 06:22

I can't believe this hasn't come up here yet... I'm so out of the loop, I have just heard of it.

A couple years ago, Björn was cool enough to share the schematic for his Folk Fuzz.
You can see the article here on Custom-Sounds:
http://www.custom-sounds.com/epages/cus ... emplate/33

Looks like an interesting variation of the ol' Fuzz Face. Interesting tricks.

soulsonic · Post by **soulsonic** » 13 Jul 2008, 06:33

Oops, I'm so out of it, I didn't realize there was already a thread for this. Well, this info wasn't there, so feel free to merge it in...

analogguru · Post by **analogguru** » 13 Jul 2008, 11:09

merged....

The basic idea comes from the (transistor) Muff Fuzz (later Little Muff Pi), which I assume predates the MXR Distortion+.

The additional components at the emitter of Q1 are for better temperature stabilization and were common in every ("better") mic-amp of this era.

The potentiometer at the input was part of discussions of the 90`s and acts similar to the input resistor of a non-inverting op-amp stage.

analogguru

BJF · Post by **BJF** » 03 Oct 2008, 07:31

analogguru wrote:merged....

The basic idea comes from the (transistor) Muff Fuzz (later Little Muff Pi), which I assume predates the MXR Distortion+.

The additional components at the emitter of Q1 are for better temperature stabilization and were common in every ("better") mic-amp of this era.

The potentiometer at the input was part of discussions of the 90`s and acts similar to the input resistor of a non-inverting op-amp stage.

analogguru

Hi,

Thanks for merging.

Yes that's likely so that the Muff Fuzz may have predated the MXR Distortion + while those are quite different circuits and both are using OP amps as I recall.

Ah, yes this is a somewhat standard two transistor amplifier and the circuit indeed acts similar to an inverting OP amp stage.

Hm, if this discussion about potentiometers at the input of an OP was being had at the internet in the 90's I would know nothing about that. However it follows from the gain equation for the circuit what a variable resistor in this point would do to an inverting OP amp stage aswell as to this stage and indeed the MXR Distortion+ also uses a capacitor and variable resitor to change both gain and frequency response.

Anyway have fun

BJ

RnFR · Post by **RnFR** » 04 Mar 2009, 19:58

i made this layout a while back, thought i would post it here since ol' torcho pulled his. it's yet unverified, but i have checked it and believe it to be correct. if someone wants to double check, that would of course be great. and as always, if you build it, let me know.

cheers.

db72 · Post by **db72** » 10 Mar 2009, 18:01

Anyone do a vero of the Deluxe version? I heard it has an extra set of diodes and LEDs you can switch in.

RnFR · Post by **RnFR** » 10 Mar 2009, 21:34

here you go! i found a missing trace cut in the other layout as well. if you build it, let me know so i can mark the layout verified.

Ben N · Post by **Ben N** » 11 Mar 2009, 03:03

The link for the article/schematic is dead. Anyone have a current link, or a copy?
TIA,
Ben

tlpruitt · Post by **tlpruitt** » 16 Apr 2009, 18:14

Ben N wrote:The link for the article/schematic is dead. Anyone have a current link, or a copy?
TIA,
Ben

Here it is:
http://www.custom-sounds.com/epages/Gag ... cles/build

Ben N · Post by **Ben N** » 17 Apr 2009, 18:25

Thanks!

BennyBoop · Post by **BennyBoop** » 28 Apr 2009, 18:57

The schem in the link has just two pots. I've seen pictures of pedals with three, is that the delux version? Anyone got a schem in that case? Or could somone point out the differences?

Cheers/Ben

soulsonic · Post by **soulsonic** » 29 Apr 2009, 22:27

I'm certain the 3-control version is the "3.5%" one. I believe the only major difference is the addition of a tone control.

noelgrassy · Post by **noelgrassy** » 01 May 2009, 10:30

Here's the one that was used with the boards designed by J Frommel & NOC3 as approved by Bjorn.
The boards a labeled "Folk Fuzz Dlx 3.5%".

Hope this helps.

BennyBoop · Post by **BennyBoop** » 01 May 2009, 21:55

Thnx.

I'll have a look at it tomorrow, too tired now.

SirElwood · Post by **SirElwood** » 15 Aug 2009, 16:45

Found this picture on the web. Maybe not much value, but it seems that not all BJF effects are gooped. https://img21.imageshack.us/i/bjfe20fol ... 35251.jpg/

BJF - Folk Fuzz [traced]