Checking out a circuit with a Si Tranny before using a Ge Tranny.

[gjcamann]

So i've got a few dollars worth of PNP Germs from Smallbear for a Rangemaster and a Tonebender. Before I put these precious babies into a circuit - i'd like to put some Si's in the circuit first to see if things generally work and measure biases etc. Anyone have any tips on if this would work, what to expect and what type of Si's to use?
Or any other helpful advice about being kind to your Germs?

[R.G.]

So i've got a few dollars worth of PNP Germs from Smallbear for a Rangemaster and a Tonebender. Before I put these precious babies into a circuit - i'd like to put some Si's in the circuit first to see if things generally work and measure biases etc. Anyone have any tips on if this would work, what to expect and what type of Si's to use?

I expect that you're going be frustrated. While some circuits will do OK-ish with this process, they won't in general be biased the same or necessarily work the same. It depends on the circuit.

As the song says, "some they will, and some the won't, and some it's just as well". The big difference in Vbe between silicon and germanium will cause bias shifts to the extent that the circuit depends on Vbe. Followers will be fine, the output DC will be a little low. Circuits with small or missing emitter resistors will be dramatically different. Use a 2N3906 for subbing PNP germaniums, 2N3904 for subbing NPNs. Might as well.

Or any other helpful advice about being kind to your Germs?

1. Look up the datasheet for the devices you got. Find out what the maximum specified voltages and currents are. If you're using 25V devices in a 9V circuit, it's hard to kill them with voltage.
2. In the datasheet, look up the PINOUT and be sure you have it right.
3. If you're worried about them, use sockets. The biggest danger to germaniums is too high and too prolonged soldering heat.

[harmless]

FWIW I had some NPN Ges for a fuzz face that I managed to put in the sockets backwards even after checking the datasheet many times and they didn't fry. I put some 2n3904s in to test the rest of the circuit and when it worked finally figured out my mistake.  In this particular circuit (and for these particular transistors) I had to slightly adjust the trim pot, but that's it.