Question about Phantom Power.

[eduardokbb]

Hey guys, I'm not sure if I'm in the right foruns neither the right section, but since it's all about audio and video, I guess someone could help me.
I'm building a little recording system and I need to know how Phantom Power works. I bought an AT3035 condenser microphone and I'm going to buy a cheap balanced Samson's S-Phantom Power Supply. What I need to know is how the Phantom Power actually works.
It amplifies the microphone itself or it amplifies the signal transmitted by the microphone? The problem here is that my soundcard Line-In supports only 6Volts. My condenser needs 11~48 Phantom Power to be powered. I need to know if connectiong the Power Supply to my soundcard and the microphone to the power supply would burn my soundcard's Line-In. Any help would be extremely grateful.
Oh, and sorry for bad engish, I'm brazilian and my english vocabulary isn't that great.
Peace,
Eduardo Barth.

 

[BoredSysAdmin]

what I would recommend is cheap outboard audio interface with balanced input for mic with support for phantom power

like this one:
M-AUDIO - MobilePre - Record Music with Your Computer

 

[eduardokbb]

Yeah I know, but the point is that I wouldn't find an outboard card with a better analog-to-digital converter of the ASUS Xonar Essence STX one at a reasonable price. In the other hand I'm afraid of burning its Line In port.

 

[TLS Guy]

Hey guys, I'm not sure if I'm in the right foruns neither the right section, but since it's all about audio and video, I guess someone could help me.
I'm building a little recording system and I need to know how Phantom Power works. I bought an AT3035 condenser microphone and I'm going to buy a cheap balanced Samson's S-Phantom Power Supply. What I need to know is how the Phantom Power actually works.
It amplifies the microphone itself or it amplifies the signal transmitted by the microphone? The problem here is that my soundcard Line-In supports only 6Volts. My condenser needs 11~48 Phantom Power to be powered. I need to know if connectiong the Power Supply to my soundcard and the microphone to the power supply would burn my soundcard's Line-In. Any help would be extremely grateful.
Oh, and sorry for bad engish, I'm brazilian and my english vocabulary isn't that great.
Peace,
Eduardo Barth.

The phantom power voltage is 48 volts. This is applied to both of the signal leads (pins 2 and 3) at +48 volts so there is no potential between them. There is a 48 volt potential between both pins 2 and 3 and pin 1 ground.

So no DC current can flow between pins two and three, only between pins 2/3 and ground.

So if you connect a moving coil microphone, no DC will flow in the coil. The microphone does not "see" the voltage. That is why it is called phantom power.

Now the 48 volts is to power condenser microphones to provide a polarizing voltage to the condenser capsule and to modulate the change in the polarizing capsule voltage with sound pressure at the capsule. So the audio signal is sent via pins 2 and 3, on top of the 48 volt polarizing voltage.

Now the power supply will not put out a DC voltage on a High Z unbalanced out.

If it put it out on the balanced 2 and 3 pins, which it probably won't, it will not matter, as there is no DC potential between pins 2 and three. Pins two and three both have an equal +48 volt potential with respect to chassis ground.

So if you sound card is high Z unbalanced or low Z balanced it should not matter either way.

 

[eduardokbb]

The S-Phantom would act like an adapter, since it has an XLR input and a balanced TRS 1/4" output. I need that because my soundcard only have the TRS input. But I don't think it will make a difference at all.

 

[BoredSysAdmin]

Yeah I know, but the point is that I wouldn't find an outboard card with a better analog-to-digital converter of the ASUS Xonar Essence STX one at a reasonable price. In the other hand I'm afraid of burning its Line In port.

The S-Phantom would act like an adapter, since it has an XLR input and a balanced TRS 1/4" output. I need that because my soundcard only have the TRS input. But I don't think it will make a difference at all.

hmmm, I don't think that ASUS Xonar Essence STX has TRS input, it does have 1/4" (6.35 mm ) unbalanced input, but it's not balanced TRS

You'd need to get balanced interface like one I mentioned or make one yourself -
Powering Microphones

 

[TLS Guy]

The S-Phantom would act like an adapter, since it has an XLR input and a balanced TRS 1/4" output. I need that because my soundcard only have the TRS input. But I don't think it will make a difference at all.

Yes, it will make a difference.

The S Phantom will need a mic preamp between it and your sound card.

Your sound card only has one high z mono mic input for Karoke.

So you will have to use the line in or the SPDIF.

You need a device that will power your two condenser microphones, and provide two stereo line outs and or a SPDIF output.

It also needs a volume control for each channel as, condenser mics often have very high output, and may overload your line in.

So the one Boredsytadmin has recommended fits the bill.

I don't know how serious you are about recording from microphones. If you are serious, rather then just playing, then you really need a mixer/DAC external sound card, with phantom powered mic inputs, like units from RME.

 

[eduardokbb]

Well, my AT3035 is a mono condenser microphone. I'm not trying to record stereo neither to record gorgeously. If my soundcard and my microphone could get me anything better than my old "webcamicrophone" (that used to record like crap) I'm happy.
I don't understand about balanced and unbalanced inputs/outputs. But let me know, if I have a microphone conected to a phantom supply and that supply has a balanced XLR input (to be connected to the microphone) and also has a balanced 1/4" output (to connect to my soundcard), my soundcard's line-in 1/4" also has to have its input balanced? And if it does, how should I turn my unbalanced soundcard's line-in into a balanced one?
Well, is there anything that you recommend me, below 100USD, that will allow me to use my Xonar STX's analog-to-digital converter to convert the signal sent by my AT3035 condenser microphone?
I beg your pardon for my ignorance, but I really don't know a thing about recording and that stuff.
Peace,
Eduardo Barth.

 

[BoredSysAdmin]

I think this might work for you
Behringer MiniMIC MIC800 | Sweetwater.com

Probably you'd want TLS to confirm this

 

[TLS Guy]

I think this might work for you
Behringer MiniMIC MIC800 | Sweetwater.com

Probably you'd want TLS to confirm this

That will work fine. It will connect to his line ins. He need 1/4 inch mono male into the Behringer output. Then a female mono connector with two stereo RCA outs as a Y connector. Then he just connects the two RCA male plugs to the female line ins of his sound card.

Then he will be set.