fronk10

Quad eight AM10 power supply
« on: July 01, 2004, 05:52:40 PM »
I'm another Newbie that needs help. The power supply for a Am10
pre calls for +/-28 vdc. The schematic shows a 36vct trafo. This
design uses a LM317 and LM337 regulators. Every 36vct trafo that
I find has a split secondary with 18v -center tap-18v. Do I need
to get a 56vct then have 28v center tap 28v? Or 72vct to get 36v center
tap 36v and then regulate to 28v? I'm real cornfused. Thanks for
any advice. fronk10


b3groover

Quad eight AM10 power supply
« Reply #1 on: July 01, 2004, 11:11:45 PM »
I have some Quad Eight CA-127 cards that I'm planning on turning into mic pre's and racking.  I'm going to use the power supply from JLM Labs.

http://www.jlmaudio.com/JLM99V.htm

You can get anything from +/-5vdc to +/-34vdc from it and still have 48vdc for phantom.

:)

Sleeper

Quad eight AM10 power supply
« Reply #2 on: July 01, 2004, 11:23:39 PM »
I'm not nearly as expert as many on this forum, but if memory sserves correctly (in other words I'm not looking at a schematic as i write this) you tie the center taps and put each of the 18v legs into the rectifier
and your all set, you should be hittting the regulators with something like 33 volts which is fine, you need to hit em with a bit more voltage than your planning on spitting out the tail end.

One thing I'm sure of, the 18v 18v readings are correct and you are using the right transformer.  hook up the transformer before you solder in the regulators and you'll see what I mean.
Sleeper

JLM Audio

Quad eight AM10 power supply
« Reply #3 on: July 02, 2004, 07:16:16 AM »
You could get the +/-28v rails with one 24vac to 30vac plug pack or transformer with our kit or you could use a 48vac to 60vac center tapped tranformer. This would give you +/-35v that the reg will reg to +/-28v and also supply 48v phantom power. And have a +/- rail free for relays normal opamps etc

Joe:-)
Joe

http://www.jlmaudio.com/shop
Capturing Audio without Injury


 

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