Germanium Transistor Gain, how much will it affect the sound?

[ericohman]

How much difference in sound is there between a 50 hfe vs a 80 hfe transistor if both are biased to the same voltage?

If I keep to the schematic and find a transistor with a hfe that gives me the correct bias voltage, how much difference in sound will it be between that and a lower gain transistor with swapped resistors (for biasing).
Both will give me the correct voltage reading (collector to ground)

If a pedal wants a gain of 80 hfe, approx. what hfe value is too low/high to be useful even after biased to the correct voltage?

[Joe Hart]

What circuit?
-Joe Hart

[ericohman]

well, that's part of what I'm wondering.

How much does the circuit really matter?
Are there any general guide lines?

[brett]

Hi

If a pedal wants a gain of 80 hfe, approx

Hey, I know that pedal !

Seriously, though, you need to suggest a circuit.  In position 1 in a fuzzface, a hFE of 50 is low and will "load down" the pickups.  This will cut treble and make for lots of "bloom" in sustained notes.  In position 2 you won't notice a difference - except with the fuzz control turned way up.  (ie past the point where a hFE>50 transistor gives a gain of 50.)  Your hFE = 50 transistor can't do any better than gain of 50 (but with a gain of 70 in position 1, combined with a gain of 50 in position 2, I think you can see that 70 x 50 = 3500, less the feedback effect, is way huge gain anyway).
cheers

[Joe Hart]

I'm far from an expert, but I know that transistor gains in, say, a Fuzz Face will certainly change the sound (but so won't just about every other component in the pedal!).  If it's too far off from the "golden" numbers, it may sound thin or weak or muddy all the way to severely gated and even not work at all.  But I'm sure some of the more knowledgeable members could give you specifics (like what happens if the gains are too low as opposed to too high and what percent deviations would cause what sounds).  But I can say that gain does matter in at least some circuits (Fuzz Face, Tone Bender, Range Master, etc.).  Sorry I couldn't be of more help than that.
-Joe Hart

[ericohman]

Thanks for all replies.

I soldered a rangemaster a few days ago. I read on geofex that the collector should read -7V so I modified a resistor (following the guide on geofex). It now reads -7V but the OC44 gain is at 50 (measured with the germanium transistor tester also found on geofex).

How important is it to measure -7V? Cause that's what I have now after replacing a resistor value, using my 50 gain OC44.

Would you suggest that I buy a tested OC44 that has a gain of around 80 instead, from a sound perspective. I'm a little bit confused of the importance of the -7V reading, maybe it's more important to focus on having the correct gain for the transistor than having it biased to -7V with a lower gain transistor?

I ask this because I also have a Maestro FZ-1 on a breadboard and I want to buy tested AC128 for that pedal (and also for my byoc 2-knob bender). I measured a few transistors I had at home but I'm going to re-measure tonight because they might have been heated from my fingers. Going to use tweezers tonight:
http://djoman.dyndns.org/germanium/test.jpg

Thanks for all the help guys.

[ericohman]

Sorry for all the questions. To keep it short:

If the rangemaster sounds good with 80 hfe OC44 and sounds best when biased the collector to -7V, then:

Would a biased 50 hfe OC44 (-7V) sound bad compared to a 80 hfe OC44 that is not exactly biased to -7V?

I haven't tested enough to know how much the bias changes the sound on different pedals. Only experience I have is the BYOC tone bender which has a trimpot that can drastically change the bass-response etc...

[Gus]

I would search this site and google.  Not everyone thinks -7VDC PNP or +7VDC NPN collector sounds the best.  There is at least one thread about this IIRC maybe more.

Sometime you just have to test stuff yourself.