Why is it that my FuzzFace with NKT275s sounds the best?

[Burstbucker]

I built two Fuzzface clones, one pedal has a matched pair of N.O.S. NKT275 transistors in it and the other one has a pair of Japanese 2SB77 transistors.  The pedal with the NKT275s is SO much better IMHO.  I was a bit apprehensive at first because the gain of the NKT275s was only in the 60-80hfe range but I tried them anyway and it sounds awesome to my ear.

The 2SB77s in the other Fuzz pedal are in the range of 89hfe for Q1 and 141hfe for Q2, they sound pretty good but nothing like the pedal with your NKT275s.  The 2SB77 Fuzzface isn't as sweet and has a lot less definition, more sloppy sounding, kinda ugly.  The NKT275s let more of the natural guitar character through and I just love that. It's warm, fat and fuzzy but still lets your guitar tone shine through, is the way that I would explain it.  Where the other Fuzz pedal is more garbled-sounding, probably because of the higher gain.
 
I'm not sure if the reason that I like the NKTs transistors so much is mostly due to the fact that they're NKT275s or if part of the reason is that the gains are more on the low end of the gain scale.  Maybe it's both?!

Anbody care to comment?

[Plectrum]

I built two Fuzzface clones, one pedal has a matched pair of N.O.S. NKT275 transistors in it and the other one has a pair of Japanese 2SB77 transistors.  The pedal with the NKT275s is SO much better IMHO.  I was a bit apprehensive at first because the gain of the NKT275s was only in the 60-80hfe range but I tried them anyway and it sounds awesome to my ear.

The 2SB77s in the other Fuzz pedal are in the range of 89hfe for Q1 and 141hfe for Q2, they sound pretty good but nothing like the pedal with your NKT275s.  The 2SB77 Fuzzface isn't as sweet and has a lot less definition, more sloppy sounding, kinda ugly.  The NKT275s let more of the natural guitar character through and I just love that. It's warm, fat and fuzzy but still lets your guitar tone shine through, is the way that I would explain it.  Where the other Fuzz pedal is more garbled-sounding, probably because of the higher gain.
 
I'm not sure if the reason that I like the NKTs transistors so much is mostly due to the fact that they're NKT275s or if part of the reason is that the gains are more on the low end of the gain scale.  Maybe it's both?!

Anbody care to comment?

Well, after hours (litterally) of swapping trannies in my FF, I settled on two lower (50-60 Hfe) gain OC44's... This lent a certain clear, tight quality to the circuit, but still it has a good squidgy feel when at full gain. Personally, I think it's more a gain and Q1:Q2 ratio thing.

Grant.

[petemoore]

  Because you haven't tried Mesa's...lol.
  Gain/leakage/test for tone...
  But remember if you like guitar rolloff to include that in the tweek/testing, also...the gain pot might could well use to be a bit larger than 1k for Ge transistor testing. Personally I don't care for the FF tone@ low gain settings, and like the gain knob set for smallest R value between the 100k and the 22uf, this can mean a 'subgain knob' between gain knob and gnd., for resistor value finding for the 'subgain fixed Resistor'.
  There are a million FF tones, properly socketting and setting up R values in a FF circuit helps to find the equations of gains in transistor matches that 'satisfy, could be exceptionally useful as breadboarding for Ge Q's in a FF Cct. to find tones it doesn't do with a stock circuit.
  Different voicings, different gain transistors [and gain setting], N/P to get a FF to sound different, trouble is refining it down to choosing just 1.
  For that I have 2 or 3, and 'race' them, have them compete for pedalboard position...I can't really tune a FF on my testamp @ low/med Volume for louder usage, nope, I like having a couple boxed and use them for a few times [once I get a decent one], think of a mod it might benefit from, or grab the other one.
  One part I find touchy to get is the brightness/amount of HF hash amount choosing...mostly I do this [after the circuits sounding good] with the Axis Face cap across the resistor between Q1's and Q2's collector resistors [usually 470-1k], maybe a touch smaller for Ge's, then a .002uf or so at the base of Q1 @ input...that and using a 100k volume knob...set...left alone about 50%-60%, then I set the volume output using the ~470ohm-1k resistor. [Actually the 1k resistors cap should be chosen after the R Value of that resistor is chosen for the output volume]...
  A ball of wax, change one thing and it changes others...

[Connoisseur of Distortion]

  Because you haven't tried Mesa's...lol.
  Gain/leakage/test for tone...
  But remember if you like guitar rolloff to include that in the tweek/testing, also...the gain pot might could well use to be a bit larger than 1k for Ge transistor testing. Personally I don't care for the FF tone@ low gain settings, and like the gain knob set for smallest R value between the 100k and the 22uf, this can mean a 'subgain knob' between gain knob and gnd., for resistor value finding for the 'subgain fixed Resistor'.
  There are a million FF tones, properly socketting and setting up R values in a FF circuit helps to find the equations of gains in transistor matches that 'satisfy, could be exceptionally useful as breadboarding for Ge Q's in a FF Cct. to find tones it doesn't do with a stock circuit.
  Different voicings, different gain transistors [and gain setting], N/P to get a FF to sound different, trouble is refining it down to choosing just 1.
  For that I have 2 or 3, and 'race' them, have them compete for pedalboard position...I can't really tune a FF on my testamp @ low/med Volume for louder usage, nope, I like having a couple boxed and use them for a few times [once I get a decent one], think of a mod it might benefit from, or grab the other one.
  One part I find touchy to get is the brightness/amount of HF hash amount choosing...mostly I do this [after the circuits sounding good] with the Axis Face cap across the resistor between Q1's and Q2's collector resistors [usually 470-1k], maybe a touch smaller for Ge's, then a .002uf or so at the base of Q1 @ input...that and using a 100k volume knob...set...left alone about 50%-60%, then I set the volume output using the ~470ohm-1k resistor. [Actually the 1k resistors cap should be chosen after the R Value of that resistor is chosen for the output volume]...
  A ball of wax, change one thing and it changes others...

no... because you have tried Mesa! 

gain. it's a good thing.