general diode question

[Martin Czech]

:::when a typical audio schematic calls for a diode but does not specify 
:::quality or size, what should be used?

Well, the question doesn't make much sense. 
What is typical, what is audio?
I think one has to recognize the function of the diode
in the schematic. 

For example:

power diode, rectifier                       : 1N4001 (?from my head, I always mix up numbers!, 
capacitance leakage, noise)
fast small signal diode                      : 1N4148 (fast means: gold doped: very leaky!!)
low knee voltage                             : Germanium OA something (leakage)
very fast, lower "knee voltage" small signal : BAT42 (schottky, even more leakage, but fast)
very low leakage                             : Gate to Source/Drain junction of jfet

And sometimes be or bc junctions of bipolar transistors.
And avalanche and tunnel diodes (called Z-diodes, the higher values are avalanche, the lower
are tunnel effect, I guess the borderline was arround 3V or so, I have forgotten...,
note that most "Z-Diodes" have exessive noise, if current starved, also with more
current there are lots that suffer from surface problems, it is 1/f noise as well,
so LP filtering will not always help).


In my next mail I will post a list of my prefered components,
not complete, maybe not 100% correct.


m.c.