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reposting -- Tonebender MK II questions

Started by MarkL, February 07, 2016, 07:36:21 PM

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MarkL

I posted this before but a typo in the title, I think, maybe led to folks missing it...

I've made a few of these, and have gone with what seems like the traditional values of ~70 for Q1, 70-80 for Q2, and 100-120 for Q3.  I've used Tungsram AC125s in these and generally, they've sounded really darned good with a few minor resistors tweaks (nothing unusual).

Over the last few days, though, I've been combing through some of the comments on some other discussion boards regarding transistor gains.  There seems to be some disagreement about whether the "traditional" values I noted above are what to shoot for, or if the Q2 gain should be a bit higher than Q3.  David Main commented that in one of his favorite versions of the circuit, the gains were quite higher (upper 100s and lower 200s Hfe), and that the Q2 gain was the highest of the bunch.  A few other people commented that they prefer this arrangement too, and that it actually led to less hiss and background noise.

Now of course, I will experiment and see what I like best, but I'm curious as to WHY some people might prefer a higher Q2 Hfe, and why it might lead to less noise.  I am going to guess that part of that may have to do with using a relatively low-leakage Q2 (since it's my understanding that Q1 needs to be leaky to work, and Q3's leakage contributes to tonal character as well).

Curious to know your thoughts.  Also...and for the record...I inherited several Mullard OC42's (NOS).  Used 2 of them for Q1 and Q2 in a Bumblebee (Buzzaround) project with a 2SB176 in the Q3 spot and REALLY liked it (also worked with a Philips AC125 and AC188).  The OC42's I have  are very, very low leakage, and fall into perfect gain ranges for the "traditional" values for a Tonebender (70-ish, 80-ish, 100-ish), but I wonder if the extremely low leakage might actually not work so well for the functionality of the circuit...

kgull

For most fuzz face type circuits, it's a matter of taste. The choice of circuit and transistors is almost a religious one. As long as the transistors aren't complete crap, the pedal will usually sound pretty good. What sounds the best is a subjective thing and goes back to that old adage "it's not the guitar, it's the player."

Case in point, I've built a fuzz factory for a band mate that he absolutely loves to death. It's pretty much his go to distortion and everyone in the band agrees it's 'him'. The other guitarist in the band decided to try it out one day but was more than happy to go back to his muff style pedal. The fuzz factory just didn't suit his playing style.

That said, do some experiments. See what works for you. To quote one of my favorite philosophers, "People almost invariably arrive at their beliefs not on the basis of proof but on the basis of what they find attractive."