One thing of which to be is that the HT+ of the Aurycle tube mikes is set very high in the power supply. The basic design of the PSU is similar to that used by the A460, those that I have seen using 5% resistors rather than the 1% in the A460 PSU.
However, HT+ in one that I opened was as high as 190v (cardioid only mic) and 175/178 in the two variable polar versions I bought. While this is OK for the tube, the polarizing voltage derived from it is far too high for most of the decent capsules around, e.g. Tim Campbell's CT-12, which should have no more than 60v. The voltage is derived from the potential divider in the mic, R3, R4, and changing one of these resistors is one solution. I personally prefer to change the zener diodes at the ouput of the PSU, D5, D6, although setting exactly 120v is a bit of a challenge!
David