Hendrix Fuzz Face

[Renegadrian]

Did a quick search but still my questions remain...
I saw some FF schematics,  and also the Hendrix one (dunlop jh2)
that schem reports the use of a couple of mpsa18, while I read somewhere that the dunlop has 2 bc108...so what's the deal?

Also, which is the difference between jh2 and jh-f1 (which uses 2 bc108)?! is the second jimi related?!
Shred a light on my doubts...

[flo]

Dunlop JH-2 (older version): MPSA18. Supposed to sound crap.
Dunlop_JH-F1 (newer version): BC108. Supposed to sound quite good.

For Dunlop marketing all of them are "Jimi related". 

[kurtlives]

There were some pedals released by Dunlop under the Hendrix name. They are complete crap though using silicon transistors with gain of over 800. They sounded terrible and are not very desirable these days.

Somewhere in the gallery there is a schem with the "Hendrix" mods that Roger Mayer supposedly did to Hendrix's wah.

Ah I just remebered... RG has them on his FF tech/info page.

[marlin]

I've actually been thinking about buying the Dunlop JHF1, saw a clip on youtube and it sounded ok. (The green one)

[petemoore]

  A sad, old marketing story IMO.
  Stick HG/LN transistors in there and it'll fuzz up even weak guitars, stick the famous [dead] dudes name on that and they'll be sellin' like hot pancakes !
  Considering that the FF tends to sound and work right after considerable luck or some modifications [including choosing matched, lower gain transistors] inside and outside the circuits box, it was an effective combination of endorsement and circuit modification strategy to use, IMo, [for a while at least].

[tehfunk]

  A sad, old marketing story IMO.
  Stick HG/LN transistors in there and it'll fuzz up even weak guitars, stick the famous [dead] dudes name on that and they'll be sellin' like hot pancakes !
  Considering that the FF tends to sound and work right after considerable luck or some modifications [including choosing matched, lower gain transistors] inside and outside the circuits box, it was an effective combination of endorsement and circuit modification strategy to use, IMo, [for a while at least].

I still don't get what is considered a matched pair when it comes to a fuzz face, do you mean one that ends up getting the voltages right? if that is the case what would be an example of a matched pair's gains? Also, can't you just use resistors to bias any set of transistors to get the right voltages and sound good in a fuzz face or is that wrong? for instance, could you get those mpsa18s to sound as good as a "matched" pair of bc108s with resistor changes? this question has been really bothering me.

[Renegadrian]

ok, let's say I am going to build a FF with 2 bc108 - Can I pretend to get close to Jimi sound with that?

[flo]

People report building the JH-F1 with a good sound:
http://analogguru.an.ohost.de/001/schematics/Dunlop_JH-F1.gif

[Renegadrian]

right, thx for the input - I am pretty ignorant when it come to fuzzes...

[flo]

I'm a fuzz virgin myself and am only repeating others. 
I want to build two fuzz faces:
- One "original" with the "correct" germanium transistors.
- One JH-F1 because of the reported good sound with cheap components.

[Der Groovemeister]

I would say build a germanium FF (with ac 128's). I built the FF with Fuller mods and it sounds just like Hendrix (before 1970). Those last few months he used several silicon versions.
See these interesting articles:
- "The technology of the Fuzz Face" on www.geofex.com
-  http://fuzzcentral.ssguitar.com/fuzzface.php
- http://www.jimihendrix.com/magazine/601/601,features,effects.html

Good luck with it.

[nico13]

  A sad, old marketing story IMO.
  Stick HG/LN transistors in there and it'll fuzz up even weak guitars, stick the famous [dead] dudes name on that and they'll be sellin' like hot pancakes !
  Considering that the FF tends to sound and work right after considerable luck or some modifications [including choosing matched, lower gain transistors] inside and outside the circuits box, it was an effective combination of endorsement and circuit modification strategy to use, IMo, [for a while at least].

I still don't get what is considered a matched pair when it comes to a fuzz face, do you mean one that ends up getting the voltages right? if that is the case what would be an example of a matched pair's gains? Also, can't you just use resistors to bias any set of transistors to get the right voltages and sound good in a fuzz face or is that wrong? for instance, could you get those mpsa18s to sound as good as a "matched" pair of bc108s with resistor changes? this question has been really bothering me.

I was wondering the same thing.

[tehfunk]

  A sad, old marketing story IMO.
  Stick HG/LN transistors in there and it'll fuzz up even weak guitars, stick the famous [dead] dudes name on that and they'll be sellin' like hot pancakes !
  Considering that the FF tends to sound and work right after considerable luck or some modifications [including choosing matched, lower gain transistors] inside and outside the circuits box, it was an effective combination of endorsement and circuit modification strategy to use, IMo, [for a while at least].

I still don't get what is considered a matched pair when it comes to a fuzz face, do you mean one that ends up getting the voltages right? if that is the case what would be an example of a matched pair's gains? Also, can't you just use resistors to bias any set of transistors to get the right voltages and sound good in a fuzz face or is that wrong? for instance, could you get those mpsa18s to sound as good as a "matched" pair of bc108s with resistor changes? this question has been really bothering me.

Can someone answer this question?

[petemoore]

  The FF is a highly variable circuit, there are many ways to alter the gain structure of the 2 transistor feedback amplifier.
  Gus, Jack and least of all Joe Gagan and RG explain it in more detail.
  Altering it drastically takes it out of the context of the thread title IME.
  A GEO article explains it.
  100hfe / 200hfe or...
  try various values of Hfe, Si transistors [also see Axis Face], with the lower Hfe candidate in Q1, rebias.
  2 Fuzzfaces raced for PB position, each had socket-transistors [chosen after poring over choices], some raised resistors [large value gets a parallel resistor stuck piggyback, above board...ez], cap on output, input cap either socketted or large [so smaller cap in wire line reduces overall value]...then ye' get yer FF's all revved up to see what you really like, in boxes, highly variable, try these trannys [rebias] hmmm...I think I liked the cleanup @ guitar volume [becomes a gain knob if it's interaction is 'so' with the FF]...and gain is plenty high like that but not oversaturatey or blistering..
  Most isn't necessary just build an Axis Face, touch of input cap mod maybe..YAFF resistor?..anyway try to beat that with #2 FF when you have all day.
  Not to say that a FF that is mondo gain isn't the ticket, worth trying one out that gets the 'in-between gains' at the guitar volume.

[solderman]

Hi
R.G has pretty much covered the area in this grate tech page
http://www.geofex.com/Article_Folders/fuzzface/fftech.htm

BTW I have built both Ge (AC128 and others) and Si (BC 108 and others) with very much the same result. When using middle hFe Ge and low hFe Si they sound the same to my ears. (I don't like the Fuzz sound but any way..) Hi gain Si transistors sounds realy crap I think. To get a good sound of a Si transistors, the trick is to use low gain transistors like the NPN 2N2222  or PNP 2N2907A and use the "Fuzz Face with Fuller mods" schematics on R.G:s page above as a base and tweak the circut from there. Then it will sound (good to thos who like it) the same as Ge ones.


To sound like Jimmy I guess one has to play like him. (since I cant this is probably the reason why I don't like the Fuzz sound )  That is more Important to the sound than the Ge mojo IMO.

//Solderman

[nico13]

People report building the JH-F1 with a good sound:
http://analogguru.an.ohost.de/001/schematics/Dunlop_JH-F1.gif

Thanks for sharing the schematic.

What gain would you recommend for the BC108's ?

[chi_boy]

Also regarding the bc108's, my understanding is that the bc108b and bc108c are progresively  higher gains. Do some of those combinations work better, similarly to the Ge?

[slideman82]

There's nothing like Ge PNP's for the FF, sounds better! Also, place a battery inside it and it will last a lot! The best you can do is a standard FF with a 2.2k resistor instead of the 470, and of course, adjust bias. Also, a DPDT with a 22n cap and a 2.2uF (both polyester) at the input will give you 2 sounds, and believe me with a 22n cap sounds amazing! Also a 2k pot instead of a 1K (this would be like Mayer's mods).

My tries on a Si FF always gave me headeaches, the were prone to oscillate easily, had to cheat it with small caps.

[petemoore]

What gain would you recommend for the BC108's ?
 Kind of depends on what the circuit does.
 Anything over Idunno...400hfe to be safe, I used 'em and went for the "cleanup with the less gain" type FF...is gonna be hard to tune down to gains like what say a 85/127 Hfe FF structure [Q1/Q2] might be.
 I found it's real easy to get the gain way up there beyond where it starts overdistorting and being gnarlytoothed gnorbgonker...opting for the cleanup/up to gain that pretty much gets the most useful range...And just Includes 'Fuzz'.
 Then you figure...guitar pickup loads the input...[even a weak pickup will distort a HG/'LN Q'd FF].
 What's it plugged into ?
 What does the gain pot actually measure across 1/3 lugs ?
 What else is going on ? Is there a LP filter involved ?
 k...shoot for having 1 or more, a low gain Q1, ~100hfe or less.
 Get a Q2 of reasonable gain in there, say...200, then swap Q1 out for 100/150 etc.
 Then play with Q2 again.
 Then forget all about that and start over.
 Don't forget to see what bias is/adjust after each swap.
 diddle with the gain knob too.
 Mostly if you want the thing to stop clipping much, and have control over gain [and nice sounds], you tune the thing to clean up too.
 Exact right gains and all that...what the gain knob is for.
 Mostly just set the thing up and bias it. Then if it's not this or that, re-voice, swap 'n rebias...then figure the thing does what it does for now.
 Then whip it out like I did my Si FF w/clipping diodes on VC, SB Gainpot set to precisely 10:17...and notice this is one dern fine treble boost, and a super sounding OD, the Fuzz [if input is compressor-boosted] it produces is generic/exotic...with highly accentuated harmonic content upon guitar attack, frequency response is tuned to produce fairly well defined lows [player needs to know this and then very well defined is it], and realize a whole new tone you'd have never recogized the box as capable of. Pretty much the Axis Face.
 It won't do that through any amppumping up any other guitar..it does other similar tricks with that stuff, a whole new setup [when any1thing else changes] requires a whole new dial in.
 Once you get a nice build of that going you might want to try to see if you can beat it with a Ge FF... they're different is what.
 Apples, Oranges, Peaches...ripe is what you want, slight irregularities may occur, this is natural, how does it taste to you ?  

[fuzzo]

I did a fuzz face sillicon (with dragonfly veroboard, tanks to him) yesterday with 2N5088 and BC550C, my god it was so noisy !! the Hfe of both transistors were 600hfe maybe too high for a regular fuzz .I tried some tricks to reduce that noise but nothing really noticeable . I'll try some BC108 or BC107 for Gilmour's tone / Hendrix's tone for a noiseless fuzz.