"FetFuzz" schem and mp3

[MartyMart]

http://aronnelson.com/gallery/Martys-layouts-and-photos/FetFuzzV1_0

http://aronnelson.com/gallery/albums/Martys-layouts-and-photos/FetFuzz.mp3

This is what it looks/ sounds like, not bad for a few parts and one knob !!

MM.

BTW if someone recognises it .... appologies !! ( I only THINK that it's one of mine )

[WGTP]

Looks different to me.   

[JimRayden]

Looks cool... I'll take a listen when I get home in an hour or two. I was expecting an all-FET circuit but this all the FET does is slam a darlington. What about two FETs wired up as a darlington. Love the simplicity and the Bazz Fuss/Clippers setup.

Whatever you do... don't do a digital redraw of your schematic. Kills half of the mojo if you ask me.

---------
Jimbo

[MartyMart]

Thanks chaps
The Jfet does indeed "SLAM" the heck out of the darlington, it's quite good even without
the 1N4001's at the back, that just adds even more "grunt" !!
Bazz Fuzz clipper setup seems to be quite sweet ....
I guess the front is a kind of fetzer valve, so a trim pot insted of the 15k may be useful
for "tuning in" the J201 .... 50k would work fine.
Mine was at 5v with the 15k so it's fine.
No need for a re-draw ... it's VERY clear I think 

mojo mojo mojo  !

MM

[Marcos - Munky]

Wow, what a nice schematic. I liked the way you drew the transistors. Also, the FetFuzz sounds great. What about to change the 100 ohm, or even change it to a pot?

[zachomega]

Sounds awesome...and I'm just in luck as I ordered some mpsa13's today!   

-Zach Omega

[JimRayden]

Odd... By looking at the schemo, I would have guessed it was a very high gain fuzz, basically a Bazz Fuss with a boost up front and clippers in the end. The sound clip sounds quite low gain though.

It does have a beautiful texture to it.

----------
Jimbo

[John Lyons]

Nice!

It's got a fuzzy compressed edge to it but there is a distortion "firmness" to it as well.
I guess it's due to the FET and MPSA13 together. then the diodes in two places.

How does it sound without  the diodes on the mpsa13?

John

[MartyMart]

It has a great "tube growl" to it when pushed hard, the clip is with a HB gtr
flat out on the bridge pup ... er I wouldn't say that it's "medium gain" !!
Without diodes ala Bazz Fuzz it's less smooth and compressed, I wouldn't miss them out 

It does one "job~" real well, doesn't clean up at all !!
MM

[mac]

What about changing the 2k7 with a 2k pot to control the drive or adding a pot after the fet?


mac

[MartyMart]

What about changing the 2k7 with a 2k pot to control the drive or adding a pot after the fet?


mac

That would work.

Wow, what a nice schematic. I liked the way you drew the transistors. Also, the FetFuzz sounds great. What about to change the 100 ohm, or even change it to a pot?

Yes, I quite liked using no symbol, just DSG and CBE    makes the specified parts pinout obvious !

MM

[mac]

If I hand draw a schematic you'll never know if it is a FF or egyptian jerogliphic 

[brett]

Very cool Marty

There's some interesting stuff in there for sure.  The 33nF cap intigues me...  I'd expect a larger value (the equivalents are 1uF in the Distortion plus and 100nF in the Bosstone).  But it's probably part of the magic here.  The output impedance of the pre-clipping stage is also more like the Bosstone (18k) than the D+ (1.2k).  So that 10k resistor on the collector is probably another part of the magic.  I wonder what the difference would be with 22k there (besides having some more gain?).

Great work.
PS values like 15k give me the poops, so how 'bout making it 10k?  The difference should be negligible.

[MartyMart]

Great work.
PS values like 15k give me the poops, so how 'bout making it 10k?  The difference should be negligible.

Caps chosen for a good "bite" and not too much low "mush"
Aha ... the "dreaded 15k resistor" !!
Needed to get between 4.5-5.5v at Jfet drain, how about a 50k trimpot ?
Yours may be 12k .... 18k ..... 20k    see what I mean 
Also the 2k7 can be adjusted at source .....

MM

[zachomega]

I've been looking over this schematic quite a bit...I had a few questions about it...

What is the deal with the j201 not being referenced to ground on the gate side of the cap?  Does that not matter?  I always just sort of assumed the cap blocked any referencing to ground for the gate.  That not the case? 

Also, the darlington is biased by the diodes?  Clever...and strange. 

And what is the big deal with 15k?  It's not like it isn't a standard part value. 

-Zach Omega

[tcobretti]

Not verified.

[petemoore]

   I built exactly the second 2/3rd's, the two clipping stages on a gain stage part. Second clipping stage I found on a switch, but I wired it in when I put it in the Sparkleboost box, [2 TB Box].
  Hot Fuzz for sure, I decided to 'double discrete' the darlington in top part of a 16 pin socket, diodes have 4 lugs per side [on the bottom half] so I could add a HF taming cap [the B/C 4148's], I couldn't find one small enough.
  That's cool because I just darked the amp down and cranked it. It's in the PB with lots of options ahead of it, and seems to have an almost infinite ablity to get increasingly [when I push the front end harder] without 'buckling' or getting overly harsh.
  I put 2n5089/5088 in the socket, then grabbed a lower ish gain to replace the 2nd half of my darlington, a tin can/4 lug 2n2222 looking Q, this put a bit of 'quack' in it...too cool, snarly and sizzling.
  Not even noisy either, surprizing, I think if the 'pre' part is quiet enough, the darlington stage is ~gated, by itself it gates a bit, an addition I wasn't expecting to place on the PB, or looking for ! Fit right in what was the Sparkle-box with the open hole really nice too!

[MartyMart]

I've been looking over this schematic quite a bit...I had a few questions about it...

What is the deal with the j201 not being referenced to ground on the gate side of the cap?  Does that not matter?  I always just sort of assumed the cap blocked any referencing to ground for the gate.  That not the case? 

Also, the darlington is biased by the diodes?  Clever...and strange. 

And what is the big deal with 15k?  It's not like it isn't a standard part value. 

-Zach Omega

Good point, the ROG Fetzer valve can be higher gain by moving the 1M to the front and using a 33k
but there's no cap on that, here it also looks to me, as you've described so perhaps it would be more
stable with an additional 1M to ground at the gate, could be my mistake here ...... it's not biased quite
so "hot" due to the 2k7 rather than a 1k5 at source.
I seem to always use a cap up front of my Jfet circuits, to block "hash and radio" getting in
otherwise I sometimes have "noise" from adjusting gtr vol pot too ... ??
Darlington receives voltage at base through diodes from collector but squashes/distorts the AC signal
here, a nice compressed sound in a Bazz Fuzz/ Joe Davisson way .... not SO clever from me really !!!

Not verified.

Looks good, and even smaller than mine, though you've ditched the power filter cap and protection
diode.
I have my 4148's on the left side of the MPSA13 and two extra strips for filtercap and ground connection
otherwise its exact
I think you can ditch the "Probably" now 
MM.

[MartyMart]

For a "Gain" pot, why not just wire a 100k off the 22n, wiper to MPAS13 base and
one lug to ground, like the fetzer volume pot

MM

[tcobretti]

Marty, I hadn't seen a layout so I put that one together. 

I haven't built this, but what supplies the distortion for this circuit?  It seems like the j201 boosts the signal into the mpsa13 when then distorts because of all the diodes.  I'm wondering if a pot between the two transistors might be another good way to wire in a gain control?