the Fuzz Face "Hendrix" mods

[mordechai]

I am told that these mods coax more gain out of the standard fuzz face circuit...and I am guessing that the 18K on the collector of Q2 has a lot to do with that (right?).  What exactly is it doing that the 8.2K would not be able to accomplish?  And what is the most important contribution that the 2K fuzz pot does compared to the standard 1K?

[blooze_man]

Read the Fuzz Face article here: http://www.geofex.com/

[jasperoosthoek]

I think what you need is a Marshall stack cranked at 11. Preferably more than one. Try to not have neighbors too if you play at home.

I don't think Hendrix' FF had these mods. Just like the Dunlop JH Wah that has an input buffer the Jimi's wah didn't have.

What kind of sound do you try to achieve? Can you name some songs/recordings? His use of effects varied greatly even on the same song on different live and studio versions.

[petemoore]

 I thought it was sad when he passed away.
  But then it got wierd and much sadder.
   Listen to the records, absorb the vibe.
    Don't listen to what's being sold unless you know what is being soul.
 

[mordechai]

I agree with many of the comments posted above regarding vibe and soul...but honestly, I am just curious about the technical effects of the modifications to the original circuit.  Let's call it the "Mayer Mods" instead since Roger Mayer reportedly did these modifications.  I am still not clear on how the 18K resistor and 2K fuzz pot alter the signal.  I know that they must, but I want to better understand what is actually happening with these changes.

[Pedal love]

There is no commonly known mod, know as the Hendrix mod by Roger. There is a fuzz pedal know as the Classic fuzz by Roger. First of all, despite many reports to the contrary, I have never seen a Roger Mayer rocket housing pedal, that didn't use Omeg pots for effect gain and output volume. Omeg doesn't make 2k pots they make 2.2k pots, which is the gain pot value of a Classic fuzz. That might not seem like much until you realize that if you multiply- 1k, 8.2k and 470 ohms by 2.2, you get within very close tolerance, the resistances of the second transistor of the Classic fuzz. Don't believe me? Here are the fuzz face numbers above- 1k, 8.2k and 470 ohms. Now multiply them by 2.2 and you get 2.2k, 18.04k and 1034 ohms(basically 1k.) The same numbers as on the Classic fuzz.

I know the guys here will take this apart, but some of you must see that these numbers are pretty much right on, for those Classic Fuzz resistances stated above.

Coincidence? Maybe? We report- you decide. Pl.

[jasperoosthoek]

@mordechai

I'm still curious about particular recordings you were inspired by, can you name a few? Or do you just try to increase the gain of the FF?

[mordechai]

@PL -- thanks for crunching the numbers!  My curiosity is really more basic in nature: what happens, SONICALLY, when a standard gain Q1 ~70-90 and Q2 ~110-130 are run through an 18K bias resistor (Q2) and a 2K (or 2.2K) fuzz pot, as opposed to running those same transistors through an 8.2K bias resistor and a 1K fuzz pot?  What do these value differences do to the sound produced by these transistors?

@Jasper -- It's not that I have a specific sound or tone in mind.  I have two sets of transistors that are higher in gain than usual -- one set is 90/160, the other set is 110/220.  I like the idea of having them provide a circuit that will give me more available gain and possibly a slightly darker tone than the typical Fuzz Face, but I want to understand how the Mayer component values -- as opposed to the "standard" values -- might affect the way these transistor pairs will work together.

[jasperoosthoek]

I don't have the answer. But you can find out yourself by breadboarding it . Install a few toggle switches and do a proper A/B test. Looking forward to the result!

[Derringer]

with a  2K fuzz pot the collector resistor will need to be increased accordingly in order to get Q2's collector to bias ~ 4.5 volts

The 2K pot will allow you to have more resistance between the emitter and the bypass capacitor which won't give you more fuzz at full tilt, but let you dial in less fuzz than the standard 1K pot.

of course I suppose in the "minimum" fuzz setting of either a 2K or 1K pot, the bypass "boost" cap is still completely shunted to ground

and yes X 1,000 ... and go back to it every few months to see if you understand more then (i do)

Read the Fuzz Face article here: http://www.geofex.com/