[sdiy] Phantom Power Supply

[Dave Magnuson]

Hi List,

I was researching a simple 48V phantom power supply, and I keep coming
across designs using the LM317T regulator.  They typically use an 18-24VAC
transformer and a voltage doubler, then rectify and regulate to 48VDC.

My question is this:  The LM317T is listed as being adjustable to 37VDC,
yet all of these designs claim a 48VDC output.  Do you think it's unwise to
use (abuse?) the 317T in this way?

I don't want to build something that's going to burn out in a year, yet the
sheer multitude of phantom supplies like this makes me think it must be
ok...  Perhaps the very low current used in phantom power avoids stressing
the part too much?

If all else fails, I'll pick up a TL783 regulator... But unfortunately I
can't get it locally (and I can get an LM317T down the street)

Thanks for your input!

Dave Magnuson

Resonant Frequency:
resfreq at hoohahrecords.com
http://www.hoohahrecords.com/resfreq/index.html
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