Advice on Hfe values AC128

[rangermaster]

Hi there.

I won on an auction 3x NOS tungsram AC128 trannys. 20€ incl shipping.

Values are:
1x 70 Hfe
1x 85 Hfe
1x 100 Hfe

All three have been measured at around 20 celcius and have a leakage less then 290ua.

Now my question. I want to build the perfect Fuzz Face clone incl carbon comp resistors, blue philips caps and i think tropical fish output cap.

What Hfe value is best to get the original fuzz face sound (hendrix years) ?
I find a lot of different info online.

Thanks again !

[mozz]

Buy 2 transistor sockets. Then swap em.

[iainpunk]

hendrix used modded silcon ff for recording, IIRC BC108, but i echo mozz and advice sockets to try by ear.

real ff's had gains all over the board, and about half the time the 1st transistor's gain was higher than the 2nd, which is frowned upon now days.

cheers

[rangermaster]

Yeah this is exactly what i meant

I hear and read different things all the time

I'll see which i like the best. I just ordered another 10 pieces Mullard's AC128.

I think i'll first try Q1-70Hfe and Q2-100Hfe. I quess that's the most used?

[iainpunk]

you could also try a low gain Si PNP power transistor for Q1, or use a normal Si PNP in reverse Beta (most transistors will work fine when you reverse the C and E, a side effect is loss of gain, anywhere from 99% to 1% of the original gain is left over, depending on the type of transistor, but quite universal between transistors of the same type.)
i good low gain Si PNP is the BD140, its a power transistor with quite low gain. a good reverse beta transistor is BC557, which loses about 65% of its original Hfe.

cheers