I have some RCA BC-2B mic preamps I am looking to pad the input with
H-pads. My question is what values do I use for the Zin and Zout to
calculate the H-pad?

I asume that if I am using a 150 ohm mic, Zin would be 150 ohms and
Zout would be the input impedance of the preamp... right?

How do I go about calculating the input impedance of the preamp? Below
is a copy of the RCA preamp schematic. Mine are stock and use the
RCA/UTC transformers. The transformer's impedance ratio is 1:100.
Sorry if this seems like a naive question.


http://www.larryseyer.com/rcaschm.gif

Thanks for your help.