Originally Posted by Jim Williams
Is that noise present with a mic connected? Are you listening without a mic connected?
To accurately hear the true noise floor you first need to terminate the inputs with an appropriate load. Solder a 150 ohm metal film resistor from pin's 2 and 3 on a male XLR connector. Now you have a proper load to listen to preamp noise.
Good thinking, Jim. Thank you.
The noise occurs with any microphone plugged in. I first noticed it with my C12 and then again with my TLM171.
I find it unusual that there is more noise(hiss) at 30db than at 50db of gain with a mic plugged in. What do you make of that, Jim?