Which connector for PSU/chassis B+ supply?

[Eusebius]

I'm trying to decide on that age old question of what connection to make from seperate PSU chassis to main amplifier chassis. the criteria I decided were essential were:
a) low cost (so no Amphenol connectors)
b) potentially large number of pins (at least 15)
c) locking (so can't get pulled out by accident)
d) at least one connector must safely take 360Vdc (equals 250v AC rating). Possibly the option of two.
e) common part, not likely to become obsolete

first I agonised over one cable or two, and decided one cable would require too high density, be hard to wire, would be expensive, and would be an uncommon part. Amphenol out the window.

next I did the calculations for number of connectors. Since I'm planning for three stages of DHTs and my system is balanced, this is what I found:
* 12 connections for the filaments of 6DHTs.
* earth
* -15vDC for CCS
* one B+ or maybe two.

that's a minimum of 15 connections. So my eye fell on D connectors. Relatively easy to wire up and available in 15 way which is nicely compact. Some are rated at 500v even, so a single 15 way D connector is not impossible.
but while I was happy with the filaments and the -15v supply on D connectors, I would really like better contacts for B+ and earth. My two choices for an added connector were:
a) speakon plugs in 2,4,8 way
b) XLRs
Speakons are cheap in four way but expensive in 8 way, so 4 way remains a possibility. I'm not quite eliminating them but I'm a bit put off by the following:
1) they're bigger and stick out more than XLRs
2) some idiot might plug a speaker into the PSU box

So XLRs. they offer the possibility of using 4,5,6 or 7 way. Now, I spoke to Neutrik about the voltage rating for these, and it's a bit more complex than you think. Some of their paperwork specifies 50v for the whole range, some specify 150v, some specify different voltages for different connectors. The sales guy in the UK quoted me 250vAC for 3-6 way and 125VAC for the 7 way. Not much agreement here, and the unbranded Chinese ones have no voltage rating. In terms of availability the 5 ways are common, 7 quite rare and gets eliminated because won't handle the voltage. Four and six way are more unusual, and six way is much more expensive. Four way can be had in cheap unbranded. So I'm thinking 4 way right now, with the 15 way D connector, because this gives the biggest pins and widest spacing so with unbranded the chances are they're OK for 250vDC, or at least more likely to be than the 5 way.

I hope you've followed all this. So any suggestions? Anything I've left out like BNC for just the B+ (high voltage)? Never used BNC but it's locking at least. Is my above reasoning reasonable? Bright ideas?
Andy

[SY]

Don't ever use an audio-type plug. It's not a matter of if, it's a matter of when someone will accidently plug the wrong thing in. Amphenol connecters at surplus are cheap; I use them exclusively. Jones or Cinch Jones connectors are likewise excellent and widely available from the scrap market.

[Eusebius]

Don't ever use an audio-type plug. It's not a matter of if, it's a matter of when someone will accidently plug the wrong thing in. >

Hi Sy - do you think that's the case with D connectors and 4,5,6,7 pin XLRs? Surely nobody associates any of those plugs with an amplifier? What on earth would they plug into a 15 way D connector, let alone a 4 pin XLR?

Amphenol connecters at surplus are cheap; I use them exclusively. Jones or Cinch Jones connectors are likewise excellent and widely available from the scrap market.>

Not in the UK, and alas, I'm in London! Andy

[mrshow4u]

all that and high voltage? Hard wire or quality connector. It could be worse than Amphenol. ...It could be Lemo, or Fischer.

And Surplus??? Oh yeah. A lot of surplus military stuff uses the good connectors (Amphenol, and others). No fun to desolder it all, but great deals.

[Bandersnatch]

Hey-Hey!!!,
I agonized over the same thing. I need to do 700V at nearly half an ampere( for each channel ). Plus AC to run the filament TX primary( no way I am going to run 16A of 5v through a connector ).

Amphenol was the only reasonable option. MS series of course.
cheers,
Douglas

[jlsem]

Amphenol connecters at surplus are cheap; I use them exclusively.

I second that. They are available on ebay for less than $10 each. I only use d-subs for signal transformers: easy-swap input transformers.

John

[tubelab.com]

I have Cinch Jones connectors on the umbilical that connects the power supply to my 845SE. There is 1100 volts in that cable. No problems, the amp has lived in South Florida humidity for 3 years. I am using a 18 pin connector. These connectors are still available through some distributors.

The 1100 volt pin is in the corner and the two adjacent pins are not used. Each supply (2 B+, 1 B-, 3 seperate floating DC filament) is completely isolated with a seperate ground lead in the umbilical. The grounds are only joined at the common star on the driver PC board. There a seperate safety ground that connects to the 2 chassis, power cord ground and all other exposed metal. It ties into the signal ground only at the star point. There are two redundant safety ground leads in the umbilical.

This arangement works very well, no hum. I would do it this way again. Put the female connector on the power supply side so there are no exposed pins on the voltage source. I would consider an interlock circuit so that the power supply can't be turned on without the amp connected.

[Geek]

One word - Molex

[poobah]

Check out AMP brand, Universal Mate 'n Lock, 600 Volts, 18 amps, dirt cheap.

Digi key has the whole line.

You will need to buy a universal crimping tool... about $30

[jlsem]

I would really like better contacts for B+ and earth. My two choices for an added connector were:

http://cgi.ebay.com/CANNON-KPSE07E12...em160037522284

http://cgi.ebay.com/CANNON-KPSE06A12...em160037522276