Power Supply Isolation for powering multiple modules

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rjb5191

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Oct 26, 2017
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Hello,

I'm working on Racking up some Mccurdy AT285 line amps as mic pre's that run on 48 VDC.  I want to power up to 4 modules (50 mA of consumption each) and was planning on using this International Power supply:

https://www.mouser.com/ProductDetail/International-Power/IHB48-05?qs=0xCm9DOQnC5e1IHcBWExhw%3D%3D

Maybe this is an obvious question but I scoured GroupDIY and couldn't find an answer.  If I connect all of the modules to the same power supply (in parallel i guess), do I need to isolate each positive power rail somehow? like using a diode in series between the power supply + output and the module on each of the 4 lines?  Or is this unneccessary?  Are there any other best practices in this area that I need to watch out for?

Also, since the modules run at 48 VDC, is there any problem with adding phatom power from the same source or would it be better to add an additional separate phantom supply?  If I can run the phantom power from the same  source would there be any isolation required and what would that look like?

thanks for any help
 

mjrippe

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Dec 27, 2011
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Those modules will have power supply decoupling caps on board, so no worries there.  And yes, you can also use that same 48v for phantom power.  How convenient!

Seriously though, you are fine.  I racked some Yamaha PM 1000 modules once that were designed for +45v.  I used a supply like yours trimmed down to 46v and the modules were happy and phantom power is 44-52v spec so who cares?
 

JohnRoberts

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It is good practice to use a low ohms series resistance in combination with PS decoupling capacitors. Further you can use flame proof resistors for another level of protection. FP resistors are designed to fail gracefully as an open circuit, kind of like a cheap fuse. This is far better than having one rogue channel take down the whole console or break the power supply.

JR 
 
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