Tonebender Mk. II transistor clarification

[Fama]

Yes, I know, there's a bunch of threads and a whole lot of information online. And that's really my issue.

I've seen some advice which aims for hFE around ~100 or so, with leakage around 200uA or so, like here: https://forum.pedalpcb.com/threads/tone-vendor-mk1-transistor-options.26965/#post-347091 (second post has advice with slightly less leakage and more hFE instead).

PedalBuilder had a set here https://forum.pedalpcb.com/threads/tone-bender-mk-ii-clone.22653/ with hFE around 200-350uA instead. That's ~double what Small Bear suggested as the maximum leakage for Q2 and Q3.

mybud posted here https://forum.pedalpcb.com/threads/two-tone-fuzz.28081/ about their unit with much higher leakages up to 1.2mA, but also higher hFE's. I did also find a mention of a vintage unit with leakage up to 900uA, so it's not that unheard of.

I forget which thread it was, but over on these forums someone mentioned aiming for ~200-300uA of leakage for all three (I think?), don't mind the hFE.

Then there's the approach from https://www.thegearpage.net/board/index.php?threads/right-voltages-on-tone-bender-mk2.1351035/ that I've also seen over on the DIYpedals subreddit which focuses on getting the bias in a certain range - around ~-8V for Q1, something like -0.2V for Q2 and either the same as Q1 for Q3, or maybe -4.5V?

So my question is, does the leakage and hFE matter or is the voltage what's important in the end? At least everyone seems to agree that some amount of leakage is needed, but how much and what is too much seems like a mystery to me. And if "voltage is king", what would be the values to aim for?

 

[Scruffie]

Yes it does matter and no it doesn't matter.

Is there a perfect Tone Bender in existence? Yes, but only to that individual user... without going back in time and measuring originals, we'll never know what the ideal gain and leakage was or if there ever was one.

You have to experiment and decide for your self, I've built Mk.II's with low gain transistors and they sounded nice and I've built them with 'high' gain transistors and they sounded nice.

Here's the readings of two units I built I remember being particularly nice, brackets indicating transistor position;
OC78D(2) OC81D (1)
0.072mA 118hFe
23hFe <500uA

OC81(1) OC81D (2)
0.566mA 65hFe
220hFe >300uA

OC45(3) OC81D (3)
0.004mA 106hfE
13hFe >400uA

And some voltage readings I have of original units from somewhere;
OC75 MkII (10K on Q1 base, 47K on Q2 collector)
Battery -9.01
Q1 c -8.50 b -0.038 e 0
Q2 c -0.13 b -0.076 e 0
Q3 c -8.29 b -0.13 e -0.08

OC81D MkII #1 (100K on Q1 base, 100K on Q2 collector)
Battery -9.55
Q1 c -8.51 b -0.06 e 0
Q2 c -0.13 b -0.068 e 0
Q3 c -8.72 b -0.13 e -0.07

OC81D MkII #2 (100K on Q1 base, 100K on Q2 collector)
Battery -9.50
Q1 c -8.76 b -0.062 e 0
Q2 c -0.22 b -0.075 e 0
Q3 c -8.13 b -0.22 e -0.14

If you breadboard and listen to the input stage in isolation trying out different parts you'll find a lot of variation in hiss, frequency response, gain... just remember that whatever his is generated in the first position is going to be amplified by the rest of the circuit but then some 'unusable' parts can be made usable with a 10nF to ground at the input.

There is no rule to follow, just use your ears.