AC128s...

[modsquad]

Scored 6 AC128 transistors for $8.   I measured the Hfe and they go from 26 to 208.   Do they normally have such a wide range? 

[Papa_lazerous]

There isnt a definite answer to this.  I have got Ge transistors and they have been mostly close to where they should be with one or two wildy out of there specified range and had batches where they are all rubbish.  Whats the Leakage like on them?  And are the real or recent chinese fakes?  I had the misfortune of getting some fake AC128's they where terrible not one was any good.  High leakage and crazy gain

[bumblebee]

i have some pnp ge trannies i scored out of some old military equipment, they are un-readable so i dont know what they are but the hfe is between 20-250.
they sound really good btw.
so yes, ive experienced a wide range in hFE, i dont know how common this is.

[soulsonic]

I got a bunch of AC128s recently, and I ended up sorting them into three ranges to use in different spots for different applications. The Low range ones were typically 35-50, Medium is 50-75, and High is 75-100-ish. The highest I measured was maybe about 130, but it had alot of leakage. With another style of AC128 I got consistently around 110 to 140 and the leakage was much lower on average. It's really a dice roll with these old germaniums and it can be really frustrating if you're looking for anything consistent.

[smallbearelec]

High leakage and very wide gain range even among parts with the same type number are the norm for germanium. The manufacturing techniques of the 60s when germanium was dominant were not anything like as precise as they eventually became. So, if you want to play, learn to sort:

http://www.smallbearelec.com/HowTos/FuzzFaceFAQ/FFFAQ.htm