Suggestions for sourcing a custom power supply

[Tarzan]

So, I succumbed to late-night eBay buying, and ended up with a piece of audio gear - minus power supply.  It takes a moderately complicated power feed - 9vAC on two pins, 16vAC on two pins, and 32vAC on one pin - delivered via XLR connector.  Power supplies for this board are scarce as hen's teeth, so before I buy another one just for the power supply, I figured I'd poll the collective knowledge of the forum.

Any recommendations for custom power supplies, at a reasonable price point?  I'm assuming I have three options at this stage:

1. Hack one together.  I've seen some posts on this power supply (or lack thereof) issue, one person modified a 32v transformer to pull two 16v taps, and 9v somehow.  Another guy posted a solution that involves two 16v PSUs (bridged on the common ground for 32v) plus a 9v adapter - apparently takes three power plugs and some creative wiring.  Even for this option I don't know where to get transformers in these voltages.

2. Find a custom power supply vendor.  I bought some transformers from a company that specializes in power supplies for tube amplifiers, I'll send them a query and see if they have any solutions.  I've also see ads online for various scientific power supply vendors that offer custom solutions, but this may well result in a power supply that costs more than the audio board.

3. Buy another unit, complete with power supply, and sell one of the units to hopefully defray the added cost.

Suggestions? 

[mkawa]

if you wind your own transformer, you can definitely have a single transformer that pulls 115vac down to 32vac, 9vac and 16vac. if the rails need to be isolated, you'll have to run a ground for each rail.

that said, you're probably better off with a transformer for each AC voltage, and not hand winding (SO BORING). go to jameco and find the AC supplies that you need in wall-wart or open frame form, add a bandpass filter in front of all the supplies (ie, wall -> bandpass -> lots of little cheap solid core transformers).

if it's taking AC, it's either a tube amp or rectifies and regulates internally. if the former, you don't have to be all that exact. if the latter, you get to be even less exact.

[Tarzan]

if you wind your own transformer, you can definitely have a single transformer that pulls 115vac down to 32vac, 9vac and 16vac. if the rails need to be isolated, you'll have to run a ground for each rail.

that said, you're probably better off with a transformer for each AC voltage, and not hand winding (SO BORING). go to jameco and find the AC supplies that you need in wall-wart or open frame form, add a bandpass filter in front of all the supplies (ie, wall -> bandpass -> lots of little cheap solid core transformers).

if it's taking AC, it's either a tube amp or rectifies and regulates internally. if the former, you don't have to be all that exact. if the latter, you get to be even less exact.

I appreciate the info!  The power supply is to fit a Presonus Central Station, and since it's solid state I'm assuming it regulates power internally. 

There have been a couple of discussions about the power supply problem on Gearslutz.com;

http://www.gearslutz.com/board/so-much-gear-so-little-time/605464-presonus-central-station-power-supply-question.html

and there's a link to a schematic for the pinout on the XLR connector.

http://www.gearslutz.com/board/attachments/so-much-gear-so-little-time/304453d1344607470-presonus-central-station-power-supply-question-central-station-5pin-xlr-schematic.pdf

Following your recommendation, I selected AC/AC adapters at Jameco, and the first page of results has both 16VAC and 9VAC adapters!  For three adapters (wall-wart style) the cost is only $35, and I've got a couple of XLR connectors on the way from Mouser.  Looks to be pretty simple to assemble a three-into-one power adapter, and cheap enough to try this option before going the custom or replacement system alternatives.

Thanks again!

[mkawa]

yah, the only thing you need to be careful of: you want a star ground topology. that is, the grounds for everything should all go to a single point somewhere that is connected to earth ground.

check up on the OEM psu specs and just make sure your individual supplies all provide at least as much current on the AC rail as the original did.

other than that you should be good to go! grats on the ebay find!

[Tarzan]

yah, the only thing you need to be careful of: you want a star ground topology. that is, the grounds for everything should all go to a single point somewhere that is connected to earth ground.

check up on the OEM psu specs and just make sure your individual supplies all provide at least as much current on the AC rail as the original did.

other than that you should be good to go! grats on the ebay find!

Just a late update for anyone who's following this thread.

Finally got all the bits together yesterday to mod up a custom power supply.  I used the three power converters from Jameco, and a Neutrik five-pin connector.  Worked like a charm, once I figured found enough spare outlets for three wall warts!

Now I'm happily listening to tunes via the headphone amp, signals fed via the Behringer DEQ2496.  Sounds amazing!

[mkawa]

wire them all together at the fuse input to a single IEC plug using zip-cord. i hate wall warts :|

[Tarzan]

wire them all together at the fuse input to a single IEC plug using zip-cord. i hate wall warts :|

These transformers are massy, heavy little blocks of iron.  I was kinda hoping they would be the type with detachable power cords, like laptop power supplies, but no dice.  I think a cheap inexpensive power strip, maybe the octopus kind, will suffice for getting down to one wall outlet.

[mkawa]

right, that makes sense. they're big dense solid core transformers in a bit of plastic. keep the plastic intact a well spaced power strip is much safer than what i'd do with them (hah)