Any recommendations? Phantom Power supplies

Posted: Mon Aug 27, 2007 9:01 pm

Well...I think the subject covers it...

The requirements:

minimum 4 channels per box
minimum 10 mA per channel

transparent as humanly possible.

Thoughts? Experiences?

Posted: Tue Aug 28, 2007 6:41 am

We have the Audio Technica version and it has always worked well. Why do you need an external box. Most mixers today have built in Phantom Power Supplies.

Posted: Tue Aug 28, 2007 12:48 pm

Of course, readers here already know my feelings regarding phantom power. But if you are going to use it, it has to be implemented really well. Any short-comings in the phantom supply network is magnified by the high gain of the pre-amp. Coupling caps have to be matched, ideally have enough capacity for -3dB@1Hz, and inherently sound good. The dropping resistors need to be low noise and matched better than 0.1% to maintain desired CMRR. Supply voltage should be solid and noise free across the audio band.

The commercial devices I have seen are utilitarian at best, not very hi-fi. And for good reason. That market is generally looking for a simple solution; something small and not too expensive. Everything I outlined above equates to a physically large and pricey product.

Posted: Tue Aug 28, 2007 2:45 pm

My very fussy mate Kostas Metaxas swears by a little box with 6 x 9V batteries in it.
http://www.metaxas.com/

Posted: Tue Aug 28, 2007 3:35 pm

I'm actually getting motorboating, low frequency oscillation, using a 40 year old Schoeps CMT441.... SR# in the 700s. T-powered. Another CMT441 T-powered SR#1053 doesn't do this. Using external 9v T-power supply takes care of the problem.... I know it's the mic that needs service, but this is the type of garbage that can get into your recording if you have mic powering that is not up to snuff.

Posted: Tue Aug 28, 2007 5:25 pm

Thomas W. Bethel wrote:

Most mixers today have built in Phantom Power Supplies.

Hey Tom -

Not giving away too much details at the moment, make the assumption that I'll have a rack full of AEA TRPs without phantom and while I'll usually use them for ribbons, I would like to be able to use them entirely with condensers some times.

The ones I've looked at so far that meet my requirements are:
http://www.sweetwater.com/store/detail/PM4/

and

http://www.fatpro.com/special.cfm?pagenum=1593 (the FPM - 4 at the bottom)

and of course the AT as well.

Posted: Tue Aug 28, 2007 6:37 pm

Thomas W. Bethel wrote:

We have the Audio Technica version and it has always worked well. Why do you need an external box. Most mixers today have built in Phantom Power Supplies.

I was going to post the same question in another forum. Our church has a Soundcraft Spirit mixer that has no phantom on the stereo channels. Someone bought a Radial DI designed for the computer hook up expecting the stereo inputs to have phantom. It is a very good DI, but is only powered by phantom. Not as interesting (or critical) application as those listed above, but it happens.

Posted: Tue Aug 28, 2007 7:02 pm

Cucco wrote:

Thomas W. Bethel wrote:

Most mixers today have built in Phantom Power Supplies.

Hey Tom -

Not giving away too much details at the moment, make the assumption that I'll have a rack full of AEA TRPs without phantom and while I'll usually use them for ribbons, I would like to be able to use them entirely with condensers some times.

The ones I've looked at so far that meet my requirements are:
http://www.sweetwater.com/store/detail/PM4/

and

http://www.fatpro.com/special.cfm?pagenum=1593 (the FPM - 4 at the bottom)

and of course the AT as well.

I would stay away from the Stewart.....Not very well constucted. We are not using our AT if you want to buy it let me know in a private email.

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