[sdiy] thermal antagonists

[Paul Perry]

Thinking a bit more about thermal problems with vactrols,
I remembered a heat sensitive diode that caused me 
severe unhappines once.
Admittedly, a zener rather than a led, but anyway...

the zener went open circuit when warm. And this was 
in a guirtar amp, where the + rail was 50V and 
the zener was part of a network that dropped this 
to +10 for a preamplifier.

Well, you can imagine what happens when a preamp
feeding a guitar amp output stage suddenly switches
from +10 to +50 supply.. the preamp surviced, but 
not the eardrums of anyone near the amp!

I don't know what was going on in the diode, but it 
was quite a reliable thermostat..

paul perry Melbourne Australia