I want a silicone fuzz, that is warm and magical like a germ

[stopstopsmile]

I want a killer fuzz
A nice 60's sounding fuzz
Silicone-for stability
Warm and cleans up like a germ-i don't buy that silicone can't be magical like the germs
uses easy to find parts, no impossible to find trannies
easy build
a nice vero layout for a first fuzz kind of guy
I like fuzzes like the DAM silicone stuff, I want gilmour type tones
I am not looking for a giant wooly overly thick

What do you suggest?  I appreciate the help. 

[trevize]

I built several FF, both silicon and germanium transistor.
I didn't find the germanium ones to be smoother or clean up better.

My favourite was and still is an axis face,
with a 2n2222a hfe=85 as q1 and a bc108 hfe=135 as q2.
The collector of q2 is biased at 4.7/4.8 v on mine.

[Brian Marshall]

a couple easy tricks to make a si fuzz behave.

dont run Q1's emitter straight to ground.  put a small resistor down there... 100R to 1k or so.
run a small cap in parallel with the bias current resistor.  (this also makes your tone knob actually increase the gain, in a fat kind of way... not a noisey kind of way)

[Shepherd]

dont run Q1's emitter straight to ground. 

On all fuzzes, or just 2 tranny versions?

[Brian Marshall]

dont run Q1's emitter straight to ground. 

On all fuzzes, or just 2 tranny versions?

sorry i should have clarified...  usually when i think fuzz, i think fuzz face or fuzz face based designs.

[Gus]

There is a link at the top  " schematics" 

[mac]

I have a Si FF similar to the Axis Face. It has a variable input cap and the roll off caps goes from base to ground, I don't like the effect of the picoF caps from collector to base, they introduce some artifacts IMHO. Transistors are 2n2219A (110,117).
I plan to replace transistors with a pair of 2n2369A, which sound very Ge-like.

If you want something stable, put a 2n2369A at Q1 and a Ge at Q2. Variations in temperature will not change the bias point, since it is Q1 which makes the temp run away.

i don't buy that silicone can't be magical like the germs

The Axis Face is the closest thing to a Ge FF. Silicons can be magical, but replace the transistors with Ge and you'll feel Harry Potter's magic wand touch. I'm constantly replacing Si in circuits which were originally designed for Si, like BMP, Bosstone, Bazz Fuss, Harmonic Percolator, etc. I plan to record some clips with both versions of the BMP. Yes, I'm adicted to Ge.

mac

[Dragonfly]

a couple easy tricks to make a si fuzz behave.

dont run Q1's emitter straight to ground.  put a small resistor down there... 100R to 1k or so.
run a small cap in parallel with the bias current resistor.  (this also makes your tone knob actually increase the gain, in a fat kind of way... not a noisey kind of way)

I'll "second" that.

I would also add that a 100pF cap to ground after the input cap sends just a tiny bit of high end to ground and smooths things out a little.

Another possibility is building this...I know MartyMart likes this one....

[Gus]

Aron how many years has this been in schematics

http://www.diystompboxes.com/pedals/gusFuzzFace.gif

[soulsonic]

Aron how many years has this been in schematics

http://www.diystompboxes.com/pedals/gusFuzzFace.gif

That made me chuckle to myself....

Folks, you need to realize that Gus is THE MAN.

He's got pretty much all the bases covered.

[stopstopsmile]

im not sure i am understanding.  I understand gus is pretty great and all, but what am I missing on this schematic issue? 

[mac]

gusFF is adapted to high gain transistors, has C4 to roll off highs, and a different bias method (R1).
And what about Aron's "The Rocket".

mac

[aron]

Yeah, Gus is amazing. Maybe in about 20 years, I will understand how he knows how to control Si transistors and make them sound great. Joe Davisson is another amazing Si guy.

[Dragonfly]

Aron how many years has this been in schematics

http://www.diystompboxes.com/pedals/gusFuzzFace.gif

i can't even remember how many years ago it was when i built that one

[stopstopsmile]

ok i am going to work on a few of these, and I will do the gus fuzzface too.  I am working on layouts but does anyone have a gus ff vero layout?  also I notice the gus ff has 2n3904, these are pretty easy to find and like .50cents a pair, which is cool but what hfe do I use or does it not matter since it has a bias control?  Can I just order any 2n3904's and not worry about hfe?  Is the gus ff highgain?  and does it clean up?

[Gus]

It was more for getting people to look around the schematic section.  The circuit is more of a variation of a VOX circuit

I traced and looked at schematics of FF type circuits and built a bunch of circuits made a chart of differences in the circuits then built a test build with fixed and trim pots for the first collector leg and the feedback and the 'bottom" of the gain pot.  If you look close it is very much like the Vox circuit in R.G.'s writeup.  So I built a bunch and ended up liking a VOX like circuit. 

Adjust the .01uf across the 1K for the lowpass filter a taste issue.

It will work with high hfe and lower hfe.  The Ic and gain was set by math and ear of the first transistor.

It is not a "true" FF because of the emitter R on the first transistor and the lowpass filter

If you look at transistor books from the early 60" this is a common circuit.  Look for the GE(general electric) 1964 transistor manual or RCA hobby manuals etc.....

Often a 820(vox) to 1.2K instead of a 5K pot will work fine.  I make the 5K external so I can go from gated to compressed sounding

As always it is a taste issue.

I have measured a common med power Si transistor that measure about 80hfe on a sencore super cricket (FF Q1 with no emitter R, rangemaster)