Variable, dual-output power supply for lab tests...

build or buy?

I have had more tube equipment repairs lately and I find that I need stable technical power more than a bench supply. Long Island Power Authority sez that a +/- 7 VAC swing is within their tolerance so no service upgrades for ME. Through a 1:4 power tranny, well, that gets to be too much.
My plan is to snag a 12VDC 10 amp supply and slamp an AC inverter on it with some filtering if the inverter is trashy.
I have the bits to build a bench supply using the JLM power station board. Dual +/- 37 VDC and P48, that's all I'll need. Switchable V and A meters just arrived today. Now for some time to build the schtupf. . .
Mike

Tracking ... and at High Power 3 amps+
Current Limiting set and other features

buy

you should find some good second hand and cheap new (china) stuf out there

but
from sub 1 amp and say switchable or variable ...
and near feature-less

build

and you can add meters and output terminals and/or multi pin connectors as you like

put three or four supplies in there


don't tell me
now you want 40volts plus ???
:roll:

I was thinking around 30v

:roll:

I'm thinking buy
you will probably get some power handling and some feautres like tracking and current limiting
...
short circuit protection

and it's ready to go right now ...


use your DIY time to make some external bench meters for Current and Volts
and some external smoothing boxes ... ( capacitors in a box )

the unit above may turn out to be a switch mode

Anyone remember this?



PRR lashed this together & I have built it on Vero but I have not as yet put it into my PSU box. Works great, but I have not put it under any major load yet.

I also have a PCB design in the works, will be made when I get back into my workshop/home.....

Peter

I vote for buy

I got a PSU made by a company called Topward (?). independant or dual tracking to 30v and a constant +5. w/ current limiting, volts and current meters (digital readouts) for each side. got it off ebay a few years ago for less than $50. for those kinds of prices it is just not worth it to build.

mike

funny you should say that, I've seen that model several times, and it sold for $200 +

Yes peterc I do remember that one. Wasn't it from an NSC app note? Doesn't go completly to ground IIRC.

Click to expand...

The lowest voltage is the voltage of the regulators.

The inspiration for this was that I could not get my 317/337 switched supply to track better than about .2v between pos & negative lines. With this schematic, the tracking was .01v between the 2 outputs.

Peter

I too vote for buy....

Here in SoCal there are at least 3 electronic swap meets ---
1 a weekend where you can find good deals on electronic
equipment. Then there's always ebay, and there are deals
to be found there too....

If you can find something in the $50.00 - $100.00 area
it's not worth it to build..



Steve @ Apex Jr.

http://cgi.ebay.ca/Bench-Top-Power-supply-Kit-3-30-Volt-1-Amp_W0QQitemZ140059309465QQihZ004QQcategoryZ294QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

think I'm gonna get two of these...

[quote author="mikep"]I vote for buy

I got a PSU made by a company called Topward (?). independant or dual tracking to 30v and a constant +5. w/ current limiting, volts and current meters (digital readouts) for each side. got it off ebay a few years ago for less than $50. for those kinds of prices it is just not worth it to build.

mike[/quote]

I've had fairly good luck with the Topwards.

[quote author="bcarso"]

I've had fairly good luck with the Topwards.[/quote]

cool! I didn't really research it before hand, in retrospect I guess I got a pretty good deal. Only gripe was the noisy fan. But I disconnected it the day I got it, now it is silent, and have had no problems. Ive rarely ask it for more than a hundred mA.

mike