Has anyone tried the germanium diode across the Base/Emitter junction on Q1?
If so I have some questions so I can include this in some builds:
1. Does it work?
2. If I am ordering some Ge trannies from Small Bear, how do I know which Ge diodes to ask for? Do they have to be within certain parameters?
3. When soldering the diodes to the Base / Emitter, would a heat sink attacehd to them avoid burning out either component- or should I try to get them into the sockets and just goop them instead of soldering altogether?
thanks!
1. i dunno
2. they are the ones
3. just have the leads touching on the other side of the board, touch your iron to the joint, and then touch some solder. It should coat the joint, then take the iron away. As long as you are keeping the iron touching components for too long you won't do any harm.
1 & 2. it works to some extent. you need a leaky ge diode. and it has to have the inverse themal properties of the ge transistor. few chances to find one.
3. use sockets if you can.
mac
I thought current flows in one direction in a diode, therefore I would think I would want a non leaky one?
I didn't know diodes leaked. I guess cos it's germanium?
I just got a response from Steve at Small Bear.
He says any Ge diode would work for that purpose. His SKU# 2209.
I noticed this fact, which I named "diode leakage", when I was experimenting with a Tonebender 3 Knob.
I have aa117, oa91, 1n60 and unknown others and I got different readings at Q3 collector depending on the reverse diode. I posted about it.
The only explanation was that some diodes were draining transistor leakage to gnd and thus increasing Q3 voltage. In other words they were acting like a resistor shunting some current to gnd.
So I put a 1k resistor in series with a reversed ge diode across vcc=9v, and I found that there was a noticeable current in some old new stock diodes.
+9v -----/////--------I<-------DDM------GND
Then I did the following: I replaced the diode with a big pot and found a resistor value that let me get the same collector voltage. In some cases diodes were like a 47k resistor!!!
New production 1n60 and of course silicons are like an infinite resistor.
mac