"Robert Casey"
As Phil noted, tubes can be noisy, but from your discription, you need a
new 12AU7.
But how do you know that? Does the noise remain if you remove the
12AX7? Are the
tubes inside the microphone itself (I'm not familiar with the CAD VX2)?
** See:
http://www.cadmics.com/vx2.htm
The noise spec ( 13 dBA equivalent SPL ) is very good - I suspect
the mic capsule runs at a pretty high DC bias voltage to get that result
with a tube head amp.
............ Phil