"Andy Evans has no Brain"

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.


** Using an RF co-ax connector for this job is totally insane !!!!

None of the readily available types are even vaguely safe as they allow
finger contact with the core terminal.

No readily available connector is entirely safe for delivering high voltage
DC and earth to an exposed chassis. There is far too much risk that due to
damage, normal wear and tear or partial insertion of the line plug in the
socket a situation arises where the DC power ground ( ie chassis earth ) is
NOT connected while the high voltage DC is.

This event will render the amp chassis live and lethal.

The same rules apply as with any mains powered appliance that requires a
safety earth - particularly that the safety earth conductor MUST NOT also
be a current carrying conductor.

Speakon ( and PowerCon ) connectors have the unfortunate characteristic
that the back cover unscrews in the fingers and exposes internal live
arts - makes them quite unsafe for use as domestic mains power or high
voltage connectors. The Speakon twists to actually connect the contacts -
making it very possible for a partial twist to connect the high voltage DC
contacts but not connect the ground contacts.

The only suggestion I have is to stick with the Amphenol 4 pin AP connector
and use 3 out of the 4 pins to carry the ground conection back to the PSU.
Make sure the cable has 4 wires in it for complete redundancy.


...... Phil