Hendrix Fuzz Face

[biggy boy]

I should now also say (if I'm allowed) that the "Tweak Fuzz" is a simple silicon FF variation I tried recently, and it is easily the best sounding 'standard' silicon FF I've tried thus far--if you want a good sound, and a circuit that is more similar to the original circuit, try it.

Tweek Fuzz?
Did you build the one using this schematic?

http://analogguru.an.ohost.de/193/schematics/SeymourDuncan_TweakFuzz.gif

[liquids]

That's the one...

I had (have) it on a breadboard, minus the 6-way input cap switch and mostly stuck with the big input cap, going for a classic vibe.  It could probably use a tone control, but to me it was rather cool as is, even. 

[biggy boy]

That's the one...

I had (have) it on a breadboard, minus the 6-way input cap switch and mostly stuck with the big input cap, going for a classic vibe.  It could probably use a tone control, but to me it was rather cool as is, even. 

Did you use 3904 for both Q1 and Q2? or whats on the schematic?

[liquids]

2N3904 for Q1, 2N4401 for Q2.  It will certainly work with other configurations, but it shined with that configuration--go figure.  Unlike many FFs, the gain pot actually has some useful range.

The schematic has that notes the transistors in the bottom corner with questions marks, but if you google "MMBT 3904" and "MMBT 4401" you get datasheets for SMD version of the said transistors. 

I just noticed that "C1"  (uh, the second one...) between Q1 base and collector is listed as 47 or 100 pf, but it works nicely as 220pf.  Smoother and more vintagey without being too dull...

[biggy boy]

I've tried making three different fuzzes, but have not found one that I'm nuts about. Would like to try another but I'm afraid I'll be disappointed again.
The last one I made sounded good on my amp but sounded crappy on the amp where I take lessons. The out put was too low. I was thinking of sticking my Gus boost after it and see how that sounded, the next time I,m at a lesson I'll try it.

[Derringer]

if you gig then just make sure that it sounds best with your gigging amp and build something else for the other amp

[liquids]

I've tried making three different fuzzes, but have not found one that I'm nuts about. Would like to try another but I'm afraid I'll be disappointed again.

I can relate - I had this issue myself for a while.  Most of the fuzzes I tried initially left me wondering just what anyone might like about them...

The last one I made sounded good on my amp but sounded crappy on the amp where I take lessons.

Fuzzes ARE 'picky' about what amp you use them on.  They are a bit unruly and often have no tone controls, and are hence dependent on the 'natural EQ' of the amp they run through.  Small speakers (typical of practice and lesson amps), overly bright or scooped-mid amp voicings tend to make what may have sounded liked a great fuzz with another amp suddenly sound amateur. 
[/quote]

The out put was too low. I was thinking of sticking my Gus boost after it and see how that sounded, the next time I,m at a lesson I'll try it.

People should note that most pedals place an output cap right off the junction of the (presumable) transistor's collector and the bias resistor (say 10k) going from 9v to the said collector.  Fuzz faces, however, do so differently.  The collector sees a bias resistor (say 8.2k), in series with a smaller value bias resistor (say,  470 Ohm), the junction of which feeds the output cap.  In short, This makes the volume seem really low as there is, for one, always at least 8.2k resistance on the output....likewise the signal is only 470ohms from the power supply voltage, which can be thought of as having similar properties to being only 470 ohms from ground = not much volume available.

An easy fix is to tap right off the said collector / resistor junction instead, or even 'balance' the two resistors-- use something like 2x 4.7k resistors in series and 'tap' the output cap at their junction instead...

The Gus boost option is an idea, but it's more parts than the above, and will affect the tone a fair amount, probably more significantly than eploring the above options...so, try both! 

[tcobretti]

You guys should really search the archives; there are zillions of FF threads, and many of us agree that the ultimate Si FF is the Axis Face over at Fuzz Central.

I have built all the classic fuzzes I can think of, and the Axis Face is still my number one.  It nails Hendrix, but also remember that he used a bunch of different fuzzes, so it doesn't nail all his fuzz tones.

If memory serves, the Si FF were more of a 70s innovation; it is likely that Hendrix only played Ge FF.  Most of the Si FF have too much gain and not much personality (the new Hendrix FF is supposed to be better but I haven't heard it - it is slightly different from the original which may in fact make it sound better).  If you build a good Ge FF you'll have a better understanding of what a FF can do, and the Axis Face comes very close to that Ge FF, except I like it more!

[spaceace76]

If memory serves, the Si FF were more of a 70s innovation; it is likely that Hendrix only played Ge FF.  Most of the Si FF have too much gain and not much personality (the new Hendrix FF is supposed to be better but I haven't heard it - it is slightly different from the original which may in fact make it sound better).  If you build a good Ge FF you'll have a better understanding of what a FF can do, and the Axis Face comes very close to that Ge FF, except I like it more!

He did use a Si FF on a few tracks, that's what my ears tell me anyway. It was VERY late in his career, like the last 6-8 months. By that time Axis was made Mayer had developed the Axis fuzz circuit, and Ge was sort of phased out in favor of Axis's sound and stability. The Axis is the circuit used on many of the famous live sets, like Woodstock and BoG.

[Renegadrian]

So the infamous dunplop pedal using BC108 is not that true to history?! Did he use one of those BC108 FF?!

[solderman]

You guys should really search the archives; there are zillions of FF threads, and many of us agree that the ultimate Si FF is the Axis Face over at Fuzz Central.

Hi
I totally agree about the Axis Fuzz Face.  Here is a link to compare an Axis Fuzz Face (Not a fuller as I see I wrongly have typed in the linked thread) and a Ge AC128 "Fuller" Fuzz Face clone circuit.  I think I have submitted this in this tread before but I can't find it so here it is again if so.
http://www.diystompboxes.com/smfforum/index.php?topic=76047.msg620484#msg620484

[Gus]

Did anyone listen to the samples in the link I posted earlier  in this thread? 
  Has anyone built this?
http://www.diystompboxes.com/pedals/gusFuzzFace.gif

Work out the gain of Q1 with the collector at about 1.5VDC

IIRC first schematic with emitter degeneration and passive low pass filter on the forums for a FF type circuit.

[jrod]

Gus, is the sound sample "70's Rock" the above circuit. It sounds really good!!!

[Gus]

All four are different settings of the same fuzz.  The circuits are very close.

[biggy boy]

Did anyone listen to the samples in the link I posted earlier  in this thread? 
  Has anyone built this?
http://www.diystompboxes.com/pedals/gusFuzzFace.gif

Work out the gain of Q1 with the collector at about 1.5VDC

IIRC first schematic with emitter degeneration and passive low pass filter on the forums for a FF type circuit.

Gus
I have etched a board with that fuzz schematic you made, it's sitting on my bench waiting for me to populate it.
It's been waiting for more then a month for me to do it. The board is not happy

[Renegadrian]

Gonna build my second FF, now I got two bc108-b which gives 315 and 355 as hfe.
Should be good enough to avoid the eccessive gain of the first FF (trannies with 600+ hfe...)

[aron]

Now that you guys mention it, my friend really liked the sound of low hFE Ge transistors in his Fuzz Face. I still have a bunch that were slightly lower gain than the "optimum" numbers. I should fool around with those.

[liquids]

I just got a batch of ten germanium from small bear and happened to liked lower hfe too...I preferred a set that was 60 and 80, if I recall, amongst a pilewith a fairly even  spread ranging from 50-140, with one in the 200s. Not that the others were all that different than this pair (the similarities between the germaniums far outweight the differences of hfe), but if I had to pick two, it turns out those were the ones I preferred.  That being said, it seemed the pair I favored each had 'tonal' characteristics that were more significant that strictly their hfe characteristics, compared to others in the same hfe range (compared to transistors that were both a bit lower, a bit  higher, or virtually the same hfe).  I should go back and compare their leakage for example...  But I definitely liked all the pairs I could come up with in that HFE range over, say 80/110 on up, etc.

I keep telling myself I should stop being surprised that I like things a bit different than most here do.  I suppose the magic numbers are subjective, too, though I previously imagined they were  golden....   

I have yet to try the silicons I have with ~60 hfe...to some degree it's all nitpicking, once you have an arrangement that inspires you....but nitpicking is what DIY is all about, right?   

[slideman82]

Yeah, Aron, you should! I think a Si FF has no chance against a Ge one... and try a 15n/2.2u polyester cap switch...

[liquids]

Gonna build my second FF, now I got two bc108-b which gives 315 and 355 as hfe.
Should be good enough to avoid the excessive gain of the first FF (trannies with 600+ hfe...)

Not sure it's been mentioned here yet...some like to 'simulate' leakage by placing a large value resistor between collector and base on one, or both transistors....try that too if you have the patience...so much to try...