I've purchased a microphone for recording (CAD VX2). It uses a 12AX7
for the head amplifier and a 12AU7 to run the line driver. I'm interested
in getting different brand tubes for it (the current X is a Sovtek and the
current U is a Phillips). The Phillips makes lotsa noise and is defective.

Anyway. Does anyone have any suggestions? I'm looking for very very
low noise, low microphonics, etc. To the extent they can add as little
color to the sound of the circuit as possible, the better.

I've looked at some of the vintage tube dealers online. I'm confused.

Thanks for any input!
--
Stephen Boyke