For buffering a mic I am looking into a PNP source follower setup:
Remove the capacitor and wire the mic/15K node to teh base of a PNP
transistor. Wire the transistor's emitter to +V through a resistor
ofo a few Kohm and wire the collector to GND (-V). Put one end of
the capacitor between the emitter and the new resistor and your
output is the other end of the capacitor. This would be the
simplest appoach to eliminating imedance loading issues.
While looking for ways to match the current transistor choice of 2N5087 so that I have a reasonable equal pair I found the MAT03 and later the SSM2220 from this site.
Can anybody explain if the 2N5087 is a good choice for the PNP source follower setup for mic signals which were already amplified somewhat by a FET. The transistor is there to provide a high impedance to the mic.
Could the SSM2220 work better than a pair of 2N5087's?
I don't need gain or not much gain. Just buffering. Perhaps even attenuation.
Anyboday care to comment?