Which of these transistors would be best for a tone bender ?

[Chris Goodson]

I found these in my junk box in some old tape players-
ac128
sb175  x2
sb178  x2
ac 127 x2
ac142
ac141
2n5172
I'm hoping to build a tone bender clone would any of(or a combination of) these work well?

[Nasse]

I´m not sure about if all types are germanium. But you should test your GE trannies for a) leakage and b) hFE. If some of these are silicon you can just use cheap digital multimeter with transistor hFE socket.

There is info at Geofex and Small Bear Electronics pages and many others.

If you are lucky there might be few suitable ones, but in general it is said dont except them all be good ones

I once bought ten new AC128´s and was lucky there was two pairs just about right. I used Geofex test method, thanx R.G it was easy

[Rick]

I've had very good results with the 2SBs. In my case they were 2SB54,173,32,33. As posted weed out the really leaky ones and give them a shot. Put in sockets for your first build and try them all. You'll probably want to keep the socketed board for testing future builds (build another soldered version for the final result). The AC128s I have were much less productive (maybe too old) than the Japanese trannies. My 2SB54 and 173 were the best of the lot. Good luck