axis face question

[jlullo]

Hey guys,
I finished putting soldering up an Axis Face last night.  I've been going through my piles of transistors to find the perfect pair.  I followed Fuzz Central's advice and ordered some PN2369A's and BD139's.  In my batch of trannys for Q2, the lowest hfe i could find was 150... it's going to be a little hot, but that's not THAT big of a deal.  The problem is that for Q1, the highest gain i could find was 57.  Is this going to be way too low?  I have plenty of other transistors, but they all are too high of gain to reach the suggested 70-90.

What would you guys do?

Jonathan

[slacker]

I'd put them in and see what it sounds like, I trust my ears much more than I trust numbers

[jlullo]

gtocha.. i'll give them a shot and let you guys know!  thanks, ian!

[burnt fingers]

The HFE range is good to find trannys that will work but I agree that you should just pop some in and see what they sound like. 

Scott

[petemoore]

  Npn's tend to bias consistantly, not a bad idea to 'chart that for a while, then once in a while at least.
  Gain is funny and all relative in FF's, Q1 position does seem a bit finicky about wanting like 65hfe - 130 or 150hfe, anything much more and it's kind ofa different sound.
  Dahh, since you have sockets...
  If it sounds weak you can bump the gain up, add R-ohms in say hundreds to the gainpot, someting between 1k - 1k8 or so seems to work, nice to have that knobs pot R min/max value  tailored to the tranny's, the SB FF gainpot taper really helps that knob too.
  I only use the last ...about 1/2  of the range on that pot.
  FF can sound great with just about any transistors, what great is in a FF sorta depends on what you like in there.
  Buncha other tranny options include...anything NPN in a neg gnd ff will work, especially 'general purpose' ones.
  Stick whatever ya got in the DMM, measure hfe [Si's are low leakage enough that simple DMM test works out good], try seeing what different gains gets ya.
  2n2222
  2n4401
  BCxxx ['different as Si got for me, 'grindy' a little.
  2n3904
     

[jlullo]

thanks for the replies, scott and pete!

i unfortunately have to run to the rat shack to get a 10k trimpot, then i'll be able to start testing some of these guys out!  i'll let you all know what i fall on.

Pete,
i was checking gain on all of the trannys that i have and the 2n2222's seem to be in the 220 range... isn't that way high?  the same goes for my bc109's and 2n3904's.. i think they were in the 300-400 range..

[mac]

There a re a lot of trnaistors out there with the right hfe: 2n2219A, 2n3440, bc141-10, 2n3903, 2n1613, mpsa42, most of them metal can.
I built mine with 2n2219A (110,117) and sounds perfect.

mac