So, I bought a component tester. I have 5 PNP Ge transistors that I have used in my continuing battle to successfully build a Tone Bender II. They started out as two matched sets (Small Bear), but one of the legs broke off of one of them, so now I have a matched set and two spares...I suppose I could use those for a Fuzz Face.
I suspect that I may have damaged some of these with heat just due to my continuing problems with this build, but I'm not having much luck Googling anything that tells me what the normal readings should be from the tester. Does anyone have a link for that info? Here's the readings. Are these still usable?
Thanks!
C-D-E are the matched set.
A
hFE 58
Vbe 134 mV
Ic 0.7 mA
Iceo 99 uA
Ices 2 uA
B
hFE 79
Vbe 132 mV
Ic 1.1 mA
Iceo 0.24 mA
Ices 7 uA
C
hFE 59
Vbe 224 mV
Ic 6.7 mA
Iceo 52 mA
Ices 1 uA
D
hFE 94
Vbe 137 mV
Ic 1.1 mA
Iceo .13 mA
Ices 5 uA
E
hFE 117
Vbe 146 mV
Ic 1.4 mA
Iceo .17 mA
Ices 4 uA
None of those look sick. hFE 50 to 200, Vbe 100mV-200mV.
Excellent! Thanks!
QuoteSo, I bought a component tester. I have 5 PNP Ge transistors that I have used in my continuing battle to successfully build a Tone Bender II.
Part of the problem with those Tone Benders is getting the right bias voltages on the collectors.
In theory if you select the parts with all the magic hFE and leakages it works. However, in reality you can do a lot better (even with only ball-park parts) by tweaking some resistors to get the right collector voltages. There's quite a few threads on this forum listing the "right" voltages.
Currently working on that. This Aion board has trim pots for Q2 and Q3. They seem useless. Especially the Q2. The range seems to do nothing for me. I may just jumper over them and find the right resistors instead.