I have some projects with 300b SET amps built on two chassis - power
supply and signal chassis. Right now I'm using amphenol 4 pin AP
series connectors for earth and HT - which is about 440v or 490vDC off
load.

I'm wondering about a simpler coax option, since I really only need HT
and earth (rest can be done with 4/5 pin XLRs and 4/8 pin speakons).
The umbilical can be fixed at the PSU end and detachable at the signal
chassis. So a female socket on the cable and a male one on the
chassis.

I have no experience of coax connectors - there's the cheap and
plentiful BNC, the more robust N type, then TNC, UHF etc etc. The
connector must be comfortable at 500v, but the other requirement would
be that the cable connector - presumably female - should be
sufficiently shrouded that it's very hard to touch since there's over
400vDC on it!!

Best choice here?

andy