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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Neutrik XLR for Umbilical

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I can only find these with 2 poles. I need something that can carry HT as well as a heater supply. Any thoughts? Do 3 or 4 pole versions exist ...

That brings up a second question. Is it a good idea to use a 3 pole with the heaters and the HT sharing a ground or a 4 pole where each has its own ground either connected at the PS, or with the heater floating? The amp is a preamp with a single tube with an output transformer.
 
dsavitsk said:
I can only find these with 2 poles. I need something that can carry HT as well as a heater supply. Any thoughts? Do 3 or 4 pole versions exist ...

That brings up a second question. Is it a good idea to use a 3 pole with the heaters and the HT sharing a ground or a 4 pole where each has its own ground either connected at the PS, or with the heater floating? The amp is a preamp with a single tube with an output transformer.

speakon has up to 8 poles for
cable connectors and also chassis connectors.
 
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dsavitsk said:
Is it a good idea to use a 3 pole with the heaters and the HT sharing a ground or a 4 pole where each has its own ground either connected at the PS, or with the heater floating? The amp is a preamp with a single tube with an output transformer.

When I built my version of SY's Heretical pre, I ended up running all the grounds back to the PSU separately. It meant I needed an 8 pin connector, (+-12V , HT, and 5 grounds), but the resulting amp is dead quiet. After I'd done so, EC8010 suggested using computer style 9 pin connectors, apparently they have quite high voltage ratings.
 
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Look up CPC connectors using google. These have the voltage ratings, pin count you need. There are vendors that sell them in sets with the pins included. (Can't remember the company unfortunately, I'll check and see if I can find information when I am at home, and post it here.)
Normally you have to purchase the contacts separately which if you only use them occasionally is a big, expensive nuisance. CPC are carried by Digikey, Mouser, TTi and others.
 
The 9, 15, 21, 25, 37-pin computer connector is military spec'd, MIL-C-83513. Amphenol has lots of different mil spec'd connectors, some quite expensive. Now, I'm not one to take electricity lightly. But I can't see any reason why Neutrik XLRs, PERHAPS even microphone connectors, can't be used. 300V and low ampere should be no problem. It seems like Leben uses XLR between the PSU and preamp. Scroll down. I doubt the MIL-C-83513 has higher rating.

I shouldn't have to say this, but one of the most important things here is to use male and female connectors right. You don't want exposed pins with 300V. In that respect, Powercons and Speakons seem to be some of the safer alternatives.
 
I looked at cpc connectors and they seem interesting, 600V and they are round so easy to make a hole in chasis.

While we are at connecting PSU and (pre)amps what is in your opinion better, just to house transformer in other box or to rectify filter and stabilize in one box and transfer to the other (maybe with some additional pasive filtering)?

Pred
 
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CPC connectors are pretty inexpensive, the problem is you usually have to buy contacts separately in quantities of 100 per, and even the plated tin ones aren't too cheap. Some vendors do sell them with the requisite contacts included.

I am sure a lot of XLR connectors would work fine voltage wise, but they were not designed for this duty. I use some XLR already in my system for audio and aes digital and sure wouldn't want to mix them up with lines carrying power.
 
While we are at connecting PSU and (pre)amps what is in your opinion better, just to house transformer in other box or to rectify filter and stabilize in one box and transfer to the other (maybe with some additional pasive filtering)?

Generally, I put the raw supply (transformer, rectifier, filter caps) in the remote box and regulator (or additional passive filtering) close to the signal circuit.
 
All true, but if you use something with a high AC rating, the DC rating, though unspoken, will be fine. I use surplus Amphenol round connectors, but you can also use octal plugs and sockets. They aren't as bulletproof as the Amphenols, but certainly there's no issue with DC voltage up to 500V.
 
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