Phantom power

  • Thread starter Thread starter MikeST
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MikeST

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Is there a simple explanation of " phantom power"?
Just bought a Marshal mic .
Said it would require "phantom power" which my 488 does in fact have.
 
XLR connector has 3 pins. 1-ground "X", 2-audio "hot" or "Load", 3-audio "cold" or "Return".

The audio signal on 3 is the inverse (negative) of the signal on 2. The input circuit takes what's coming in on pin 2, and adds to it the inverse of the signal on pin 3 (which was already the inverse of pin 2, right?). What you wind up with is effectively double the signal on pin 2.

Now, let's put the SAME signal on pins 2 and 3, instead of putting an inverted signal on pin 3. The input flips the pin 3 signal, and adds it to the pin 2 signal and you get -- NOTHING.

Make that "signal" 48 volts DC (with reference to pin 1), and you have a DC power source that disappears at the input. Hence the term "phantom" power.

The DC signal does not interfere with the audio signal, so there's no problem carrying both on the same wires.

Simple enough?
 
A few condensor mics can use a battery instead. But they all have a built-in pre-preamp, and so must have a source of DC power.
 
Thanks guys.
So my 488 is basically proving that by having a couple track providing phantom power ?
 
Yes sir e Bob, er..Mike! :D

That is if you have the 488MkII.

I don't think the original 488 had it built in.

Cheers! :)
 
Ghostman,

I panicked for a second. My deck is at home. But its a 488...
not a 488 MKll

But I looked at e-bay just now for specs on a couple of 488's that are listed. It looks they do have phantom power on 1&2.

I know some of this stuff is routine to you guys, or possibly in the back-posts. But this forum is a big help to new people. Sometimes topics that are a re-hash to some people, really do help out a lot
Thanks.
The manuals on the units are great, but they don't tell the you the kind of information you should be asking before you buy, only aftre you get them do you realize.
 
Very cool. Thanks.
With that , I'm powered up for any channel correct?
 
For any channel that has a microphone input, yes. If you only have a line input, you need a preamp. Many preamps have phantom power built in.
 
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