2n647 transistor

[The Iron Chef]

Hello all,
I'm new here and also to building effects. I've built a bunch of effects from the usual web sites with varying degrees of success. All fun 'tho.

Now, I've come across a box of 2n647 transistors. I think that they're from the late '50's and are germanium. My question is: in what circuit could is use them to for best result? Are they anything special? search within this forum = 0

tia
-Keith

[Dragonfly]

FIRST:

Go to www.geofex.com and read "The Technology Of The Fuzz Face", and pay special attention to the "testing germanium transistors for leakage" section.

After you've tested them and found the leakage and ACCURATE HFE's of the transistors we can give some advice.

To at least give you an idea though...and assuming the transistors are good.... things like Fuzz Faces, Tone Benders, Maestro FZ-1's, Rangemasters, etc are all good germanium transistor circuits.

Welcome to the forum.

Oh...and a special thanks for "searching" before asking...you'll find that the "vast majority" of questions have been answered here, any times ver.

[drewl]

A google search comes up as a silicon PNP UJT.
I had one turn up in a Kay guitar with built in effects.

[Dragonfly]

If its a UJT, thats a whole 'nother matter.... 

[The Iron Chef]

Thank you for your answers and suggestions. I'm in the process of building a leak checker as described at geofex. I'm going to use a bourne  5k pot instead of the 2.472 resistor. I can calibrate it before every test session, right?
Drewl, My searches have found the device to be a germanium NPN medium power.  not PNP or  "UJT". The device is shown on this web page http://www.transparentsound.com/transistors/vintage-transistors/rca/rca.htm Scroll down to 2n647.
-Keith

[drewl]

Well the only way to be sure is to measure it with a meter.
The one in the Kay guitar I worked on was used in an oscillator circuit.





http://www.datasheetarchive.com/2N647%2F22-datasheet.html

[Mark F]

Well the only way to be sure is to measure it with a meter.
The one in the Kay guitar I worked on was used in an oscillator circuit.





http://www.datasheetarchive.com/2N647%2F22-datasheet.html

That link says it is an obsolete GE low power transistor