Fuzz Face Transistors

[Ofek Deitch]

Hi everybody

I really wanna build a fuzz face and I got two 2SA12 PNP Germanium transistors.
I heard that Q1 should be around 80 Hfe and that Q2 should be around 100Hfe, but I'm not sure how to check what mine are.
I found the circuit on geofex (http://www.geofex.com/Article_Folders/ffselect.htm) that you can measure the transistors with but I didn't really understand how to use it.

When I connected one of the transistors and measured the voltages between the 2K4 resistor, while the 2M2 was disconnected I got 0.05, and when I connected it I got 0.66.
With the other transistor I got 0.01 when the 2.2M resistor was disconnected and when I connected it I got 0.24.

Is that good? Could someone explain to me what should I do in order to find out whether they will sound good or not? And has anyone tried these type of transistors before?
Thanks !!!
Ofek

[fpaul]

Haven't done it in a while, but from rereading;

.05/2472*1000000=20ua leakage

(.66-.05)*100 = 61 gain

[fpaul]

This is actually a good start to learning ohms law.

V=IR

The current leaking causes a voltage across the 2472 resistor.  You measure the voltage and know the resistance so you can calculate the current in amps.  It's very small so multiply by 1000 to get ma, then another 1000 to get ua.

I've made fuzz faces with gains of 40 - 60 and they sounded good to my ears.  I'm guessing that lower than 40 would be pushing it but I haven't tried it. 

[LucifersTrip]

When I connected one of the transistors and measured the voltages between the 2K4 resistor, while the 2M2 was disconnected I got 0.05, and when I connected it I got 0.66. With the other transistor I got 0.01 when the 2.2M resistor was disconnected and when I connected it I got 0.24.

you have a 61 and 23 hfe. the 1st could be used for Q1, but you probably need 70-90 for Q2

though, you might be able to pull this off
http://www.luciferstrip.com/fuzz/fuzzface-fy2-mod-variable.jpg


good luck

[Ofek Deitch]

though, you might be able to pull this off
http://www.luciferstrip.com/fuzz/fuzzface-fy2-mod-variable.jpg

Are you suggesting I should put a cap between the Collector and the Base of Q2?
And should I use the 23Hfe one as Q1 or Q2?

Thanks everybody for the great advise !
Ofek