When you're bored, build power-supplies.

[G6Tanuki]

So, over the christmas/new-year I was a bit bored. On the shelf I had a mains-transformer - outputs 250-0-250V 75mA and 6.3V 3A - I'd got this from 'Greenweld' a while back. Then there was a stack of Sprague mil-spec 47uF 450V electrolytic 'cans' [rated for -30/+110 Centigrade at up to 110,000 Feet altitude].

And I had a little GEC CV4005 [U78/6X4] valve.

Add in a RS-Components "509-995" diecast box and it somehow all came together: there's a 270-Ohm resistor between the two electrolytics.

I sprayed the diecast box with traditional black-crackle, and fitted a 1960s MK plug.

Question: what sort of output-socket should I use? So far I've used flying leads to hook it up to a few radios.

Should I use old-style 'Plessey-plugs'?

Bulgin "Buccaneer" types? http://www.bulgin.com/products/circu...onnectors.html

Or maybe the classsic "Jones" plugs? http://www.cinch.com/products/misc-c...plugs-sockets/

[mole42uk]

I use 4mm binding post / sockets on all my power supplies, I use a lot of interconnect leads with 4mm plugs on which fit croc clips and all sorts of other connectors. If all else fails I'll wrap the stripped end of the wire around the binding post......

[TonyDuell]

One rule I have which is NEVER broken is not to use any connector normally used for mains for anything else. The risk of confusion is too great.

For the output of a power supply it depends on whether it's a power supply to be used with one or more finished projects, or a unit for my workbench for experimental use (mainly). In the latter case I would use 4mm sockets or terminal posts. In the former case, perhaps a mini-jones plug, or one of the Bulgin ones not normally use for mains (there is, or at least was, a 4 pin one with shrouded pins on the plug).

Of course nothing stops you from having both if, say, it's a PSU that lives on the workbench and is used for both experimental work and for finished devices (perhaps small pieces of test gear).

[G6Tanuki]

Congrats on interesting suggestions regarding power-output sockets.

Agreed on the need to use something 'unusual' to prevent inadvertent mating. Equally, I don't want to veer off into the realms of the output-socket costing more than the rest of the PSU cost to build.

"D" connectors are an interesting option: though most people associate these with 9/15/25-pin RS232/V24 or RS487/488 data links, the basic "D" shell can house some more-interesting services: my RACAL RA217/RA323 uses the classic 25-pin outline D-connector to handle various DC voltages and 240VAC.

[ms660]

Jones socket for me, you can always stuff wires in willy nilly for a hook up....I like the paint finish.

Lawrence.

[G6Tanuki]

I'm minded towards Jones sockets too: in this case the 8-pin variant could deliver 4 strapped-in-parallel pins for chassis-to-chassis ground, 3 pins for heaters and 1 pin for the distinctly-light-duty 70-odd-milliamps of HT.

And Jones-connectors also come with that classic crackle-finish which matches well the historic quiddity of my old-style power supply.

[David Simpson]

Nice wee project, G6Tanuki, very neat. I too shared your festive season boredom. As did quite a few Homebrew enthusiasts, I suspect.
Jones Plugs - me too. I've used them on several projects.

Regards, David

[ms660]

Originally Posted by G6Tanuki

And Jones-connectors also come with that classic crackle-finish which matches well the historic quiddity of my old-style power supply.

Wouldn't mind knowing the brand of crackle finish paint and the technique you used.

Thanks.

Lawrence.

[Diabolical Artificer]

I'm with Richard as regards 4mm banana sockets jacks. It means it's easy to connect your DMM as an ammeter say or other PSU's etc. I too have an assortment of leads with croc clips and wotnot on.

Nifty little PSU. I like making PSUs, very therapeutic as they arn't to complicated and are quick to knock up.

Andy.

[G6Tanuki]

Originally Posted by pwdrive

Wouldn't mind knowing the brand of crackle finish paint and the technique you used.

Its this: http://www.frost.co.uk/vht-black-wri...ish-310ml.html

I cleaned up the diecast box with a brillo-pad then gave it a very thin "misting" of U-Pol Acid #8 etch primer - just enough to conceal the shininess of the aluminium. Left this to dry for a day or so then popped it in the bottom of the oven after roasting a chicken, to fully harden it.

Then sprayed the VHT wrinkle-paint at a temp. of around 20C. Leave it quietly alone to do its wrinkling-thing then a couple of days later it went back in the bottom of the oven (this time after roasting a beef joint).

You need to remember that the wrinkle-paint will remain slightly soft for some days after application and so it's rather easy to damage the finish if you're too hasty fitting components to the painted surface! Baking it at 50C or so improves durability I find.

[G6Tanuki]

Originally Posted by Dr Wobble

I'm with Richard as regards 4mm banana sockets jacks. It means it's easy to connect your DMM as an ammeter say or other PSU's etc. I too have an assortment of leads with croc clips and wotnot on.

I personally don't like using 4mm bananas for 250+ volts: on many of them there are exposed metal-bits even when mated.

Right now as far as preference is concerned I'm biased very much towards Jones-sockets but with Octal plug/sockets or NATO connectors distantly following up the rear.

This little PSU will come in handy as I'm intending to get back into the habit of building small regenerative receivers (the classic 1-V-1 type things using EF39/6K7/ EF91/EF50 type valves that every aspiring SWL cut their teeth on in the 1950s)

[ms660]

Originally Posted by G6Tanuki

Its this: http://www.frost.co.uk/vht-black-wri...ish-310ml.html

Cheers for that, VHT seems to pop up in various forum threads, it must be the biz.

Good luck with the regen projects, my favourite topology.

Lawrence.

[bikerhifinut]

From a relative novice.
I have some kit preamps from a well known british supplier of valve amp kits.
They use a separate PSU, common to phono and line amps.
The power is distirbuted via "Binder" plugs and sockets which i believe are available from farnell etc. They have a socket on the PSU output and a panel plug on the amp input side so that no bare pins will have HT on them.
They are obviously OK for up to 300V or I am sure they wouldnt be supplied for use with the kits, which work on 250V or thereabouts.
I used normal 4 core lighting flex 250V AC for my power leads.
Hope that is of use?

Andy.

[ColinB]

What about a socket taken from an old HT battery, so a set can be plugged straight in? Not sure there was ever any standard for these, does anyone know? Maybe 4mm sockets in parallel (even switched if you're really keen!) to allow for something more 'fun'...

[Herald1360]

Octal valve socket? Used by period amp builders for similar duties.

6.3V on 2&7

HT on 3

0V on 8

[joebog1]

I hear you Herald1360!!
BUT, today find me a decent octal plug with a SAFE cover!!
400 volts on the fingers of one hand causes burns and HUGE amounts of swearing.
To add to that find, me a decent line socket with SAFE cover!!.

with best regards
Joe

[Herald1360]

Gut an old plug in relay, perhaps? Would look a bit odd, though.

http://www.angela.com/eightpinqqqoctalpinplug.aspx

looks possible.

Bulgin ones are available but with audiophool price tags.

[Radio Wrangler]

The old wander plugs used for radio HT batterie fit nicely into the inside bore of a bit of copper brake pipe. The pipe can be araldited into holes drilled in perspex. I shaped the inside end of the copper pipe to make solder lugs.

David

[G6Tanuki]

The problem with octal sockets - apart from the safety issues mentioned - is that I can't seem to find a supplier of the kind I was thinking of, that have a screw-on bakelite rear cover and Jones-plug-style cord-grip.

I've never seen a Wander-type socket that has any form of cord-grip or insulation of the rear; equally, I don't like the idea of them for 250+ volts!

Jones, Bulgin Buccaneers, and the Plessey type plugs/sockets as used on the likes of the old Larkspur and the more-recent Cannon version on Clansman gear, do at least offer free-sockets with proper cable-clamping.

[G6Tanuki]

Originally Posted by Herald1360

http://www.angela.com/eightpinqqqoctalpinplug.aspx

looks possible.

Bulgin ones are available but with audiophool price tags.

Thats the sort of octal plug I was thinking of - but I can't find the octal line-socket equivalents I remember from yesteryear.