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D Voice · Been Here Awhile Joined: 26 Jun 2010 Posts: 232

This is diverging from another thread (thanks George). Perhaps hardly worthy of a thread of its own, but gotta ask:

Is there much noticeable difference in phantom power supply boxes, especially the 2-channel variety as it pertains to voiceovers?

What should one be looking for?

heyguido · Posted: Sat May 05, 2012 7:01 am Post subject:

True 48v power. Many manufacturers claim phantom power, but actual output varies from box to box. Some even deliver as little as 25v. An underpowered mic can underperform, to the detriment of audio quality. Some mics can handle it, but many quality mics suffer when not fully powered. I'm sure George and Frank can elaborate on specifics.

I personally discovered this when I picked up a Focusrite, and discovered a couple of previously undervalued gems in my mic closet sounded much better when fully powered.
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Limerick Lane Audio · Contributore Level V Joined: 13 Jan 2012 Posts: 151

D Voice · Been Here Awhile Joined: 26 Jun 2010 Posts: 232

heyguido · Posted: Sun May 06, 2012 7:17 am Post subject:

Sorry to confuse.... I was being general, for the benefit of others, as this is a common problem that many overlook.

In my case, it's a pre with phantom power, but the issue applies to both, though most users here are probably getting their power from the pre...

The problem occurs most often with cheaper gear, and particularly with usb interfaces, which are used by many.... As the typical usb bus delivers around 5v output, you can see how it's tough to get 48v out of an M Hobo Tounge

or mbox mini.

That said, some mics are more tolerant than others of low power situations. YMMV.

As for testing your rig, a simple multimeter will do the trick... However, I defer to the pros (George, Frank, etc) for specifics on how to do it safely and correctly.
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Frank F · Posted: Sun May 06, 2012 11:34 am Post subject:

Don is "spot on". The best a USB connection can offer once voltage multipliers are added is +-27 vdc. therefore under-powering a mic which is designed for +-48vdc. Some USB pre-amps; including those made for Digi-products; only supply +-17vdc. Most USB Hobo Tounge

supplies/pre-amps with a wall-wart (external power supply), will provide a full +-48vdc.

There are a lot of Hobo Tounge

supplies out there. Many prosumer models; both single boxes and pre-amp added; are only powering to 27vdc. This voltage discrepancy can be verified with a multi-meter. Caveat: Be extremely careful!!! Although the voltage is low, it can knock your socks off or worse. Check in the cable, not the "box".

Douglas, you mentioned ART, Behringer, and Nady specifically. Some of the Hobo Tounge

supplies by these manufacturers will vary in voltage and many, many, many are noisy due to the use of zener diodes in the boxes. Lower priced units are usually "prosumer" at best.

Don't forget to notice that many USB preamps cannot take a full 48vdc for a separate Hobo Tounge

supply. Many more do not have the ability to use "line-in" without going through the preamp.

Personal thought: If you want a "box" which works the way it is supposed to - spend a few bucks and buy a good one. This is true if you are wanting to be mobile with your set-up.

True power can make your condenser microphone sizzle.

Frank F
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georgethetech · Posted: Sun May 06, 2012 3:25 pm Post subject:

Here's a brief explanation how a properly designed USB powered device can actually create 48V phantom power. (yes, i know it's by CEntrance).
The MicPort Pro seems to work beautifully with the 416 P48 model, which specs say requires 48V +/- 12V to operate. I would think the noise floor would increase if the 416 were being starved for power, wouldn't it?
Definitely check the specs of any phantom supply to be sure it is outputting a true 48V. Just because it says it provides phantom power, doesn't mean it provides 48V.
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Frank F · Posted: Sun May 06, 2012 5:00 pm Post subject:

Interesting article although flawed in many respects. David a user of the M Hobo Tounge

points out the power truths and equations but fails to take into consideration that MOST USB ports supplied on the PCB do not reach the maximum power of 5v, 500 ma and are not powered ports. This is especially true in laptops.

swduncan · Posted: Mon May 07, 2012 5:34 am Post subject:

For what it's worth, my Shure x2u is 49.27v, but that is with no load. I wouldn't expect it to be much lower under load - what does a mic draw? A few ma?

Frank F · Posted: Mon May 07, 2012 10:13 am Post subject:

To paraphrase an old song: "The answer my friend is blowing in the wind". Each mic will vary. And I repeat EACH mic, even from the same manufacturer, will vary.

If you have 49.2 v, under no load, you are actually getting approximately 44 to 47vdc under load. That is good. But then again, Shure does not make too many prosumer items. The question now is many milliamps is the x2u putting into the mic circuit?

Frank F
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Be thankful for the bad things in life. They opened your eyes to the good things you weren't paying attention to before. email: thevoice@usa.com