Phantom power?

[chessrock]

Just wondering if anyone knows how I might get around the whole phantom power issue. I just realized through some more recent posts that the phantom power on one of my preamps may not be quite up to snuff.

Does anyone know if this is something that can be taken to a technician and have them fiddle with it?

Are there any other means of delivering the proper voltage without shelling out a lot of dough or degrading the sound? I really like the clean sound I get out of this thing and I'd hate to have to give it up.

Thanks!

 

[Buck62]

They do make units that supply 48v phantom power that are not preamps, but I'm not sure how quiet these things are.

Anybody?

Buehler? Buehler?

 

[Lame Thrower]

Rolls makes a phantom power box. Sometimes you can find em on EBay for <$20.

Also, Harvey gave some instructions on how to build one from stuff you might have around the house awhile back.

 

[atomictoyz]

I think Harvey would be doing us a favor if he could post a performance relationship to phantom power inadequacies. I think he should maybe also give specific instructions to how to test and where to test. For instance when I got my MD8 I was worried about its pre amps and its phantom power, so It was nice that my father came over an ran some tests for me. He is a electrical engineering specialist, degreed at that so he is more than qualified. He showed me how he does it with his equipment and how not to blow up his equipment. MD8, 46 volts at the end of 20 ft XLR cord.


Peace,
Dennis

 

[Lame Thrower]

Yeah, I've been searching for that info for awhile now. My POS Behringer mixer only puts out 23v phantom power, and I'm curious what the limitations of substandard voltage are. I'd be interested to hear from someone that knows what they're doing.

 

[ozraves]

Rolls makes a phantom power box. Sometimes you can find em on EBay for <$20.

Also, Harvey gave some instructions on how to build one from stuff you might have around the house awhile back.

the rolls is not 48v. i think it's about 44v when i tested it.

 

[Harvey Gerst]

The standard is officially 48V DC, +/- 4 volts. That means anything from 44 volts to 52 volts is within tolerance.

Okay so what happens when you under power an externally charged condenser capsule? For one, your output goes down and your noise goes up. You'll lose some top end and it won't handle as much power as it did. Will it sound bad? Maybe, maybe not.

For example, the Lomo 33mm capsule is designed for a 70 volt polarizing voltage, but at 48 volts out of the Oktava MC012 body, it sounds very warm and wonderful.

 

[crawdad]

I got curious and measured the phantom voltage of my mixers and pre's that have it.
Here are my results:

Yamaha Promix1: 45v
ART Tube MP: 45v
Mackie 1202 original series: 41.1 v
Behringer Ultra-Voice Pro: 48.2v

 

[Lame Thrower]

Thanks Harvey. Would the same symptoms apply to an electret such as the ECM8000? I understand they only require a 15v polarizing charge?

I'm finding it very difficult to get an acceptable S/N ratio out of my ECMs. It's probably more likely my room acoustics and noisy computer I guess.

 

[Harvey Gerst]

No, electrets are different; they come with a polarizing voltage already there, so they're only using a small part of the 48 volts for the electronics and essentially ignore the higher voltage since it isn't needed.

With any very small electret, a low noise preamp is critical. These suckers don't put out a lot of signal. For loud sources, a small electret works fine. If you're not getting enough signal, you may have to move the mic a lot closer to the source.

 

[ozraves]

I got curious and measured the phantom voltage of my mixers and pre's that have it.
Here are my results:

Yamaha Promix1: 45v
ART Tube MP: 45v
Mackie 1202 original series: 41.1 v
Behringer Ultra-Voice Pro: 48.2v

which one sounds best to your ears? of the inexpensive pres, i've found the audio buddy to sound the best and it's phantom power is about the same as your mackie.

 

[Lame Thrower]

Yeah, I get usable results when I mount the mic on the bridge of my upright bass, but when I try your over the shoulder guitar technique, the noise becomes unbearable.

Thanks very much for repeating yourself here, as I'm sure this was covered in the "big thread", and sorry for derailing your thread Chessrock.

 

[Harvey Gerst]

Making your own Phantom Power Supply

And here's the link to my post on making your own power supply:

https://homerecording.com/bbs//showthread.php?s=&postid=270494#post270494

 

[crawdad]

ozraves--I can see where each could have its own applications. The Mackie sounded a bit dry, the Tube MP seemed fatter in the low end, the Behringer sounded the most transparent, and the Yamaha Promix1 sounded very balanced.

I forgot to mention my PAIA Project R tube mic pre. Phantom was 49v on that one. The PAIA is definitely to get color. Usuing the tube drive and mixing a bit of that in gets you into rock and roll territory. I'd use it if I wanted a little grit in my vocal track.

One of these days I need to buy a preamp that costs more than 129 bucks.