[sejarzo]

The E-MU 0404 USB comes with a 5VDC/1000mA switching supply, and my desktop PIMETA came with a 24 VDC switching supply. I would like to build a single box with a couple of TREADs to supply both components with a linear supply. The 0404 needs 5VDC, but I could live with a lower voltage for the PIMETA (it sounds just fine on two 9V batteries in series, and I run it on the road with an 8XAA adapter.)

Anyone know of a particular transformer with dual secondaries that would work in this situation? I'm OK at building, but not designing--but it seems to me that running the lower voltage at higher current draw would create heat issues if I used a typical dual that would provide something like 12 and 24 V.

Thanks in advance for any advice!

 

[heatmizer]

you want to install the emu and the pimeta into same enclosure?

how about something like 2 "Treads" and not use the switching power supplies at all and use 1 larger power supply for the pimeta and emu.

use like a 18 volt single supply and power both "Treads" from it

 

[regal]

you need to determine the draw of the 0404, it is much over .3 amps, it will probably require a separate transformer or a very large heatsink. Tangents website has a power supply estimator which is very useful.

 

[sejarzo]

Quote:

Originally Posted by heatmizer /img/forum/go_quote.gif how about something like 2 "Treads" and not use the switching power supplies at all and use 1 larger power supply for the pimeta and emu. use like a 18 volt single supply and power both "Treads" from it

Umm, when I read my OP, what you suggest above is exactly what I asked about.....or that wasn't entirely clear, perhaps? Maybe I should have written:

"I would like to build a single box with a couple of TREADs to supply both components with the appropriate voltage from separate linear supplies, with a single transformer feeding both."

The problem is that stepping down 18VDC to 5VDC with a TREAD effectively turns 13/18 of the power into heat, which is why one typically uses a transformer that puts out only 3V or so more than the desired output voltage.

I know that Elpac makes some triple output voltage supplies, but I don't know if they are linear, or if they use a special multi-tap transformer. I was just hoping that some one might know how best to do that.....and cut down on the number of wallwarts that I have to carry around, in addition to providing a cleaner supply.

 

[tangent]

Quote:

Originally Posted by sejarzo /img/forum/go_quote.gif I know that Elpac makes some triple output voltage supplies, but I don't know if they are linear

Some of them are. The WM072 and WM075 are linears, and probably avoid the heat problem just as you're guessing: by use of a multi-tap transformer. I assume this because they're relatively small, and in plastic enclosures.

If you wanted to DIY this, the best reason would be to get a cleaner supply voltage than a commercial unit can offer. And, with such a high current requirement on the lower voltage, you do indeed want to use a transformer with a multi-tapped secondary. If you can't find one, I'd re-examine how badly I wanted to get away with just a single transformer. Maybe the real problem isn't the transformer count, but the box count.