phantom power for condenser mic

[patknk939]

Hi. Have a problem with power supply for condenser mic. Got this EV Co11 condenser mic that is not self-powered by AA battery but needs phantom power. My equipment is nothing like professional audio mixer but just ordinary mixer for karaoke purposes (naturally it doesn't have XLR inputs). So, does it mean that this EV mic is practically useless to me? Is there any ways to get round this problem (replacing the mixer is out of the question), like getting external phantom supply (if there's diy supply, that would be awesome)? Appreciate advices. Thanks.

[Iain McNeill]

A phantom can be kitted up pretty easily. Traditional phantom is +48VDC fed through separate 5-10K ohm resistors to the +ve and -ve leads of the XLR (check which is which) The ground pin of the XLR goes back to the -ve terminal of the 48V supply.

I used a stack of 32 AA batteries once (because I got them free) and it was a very quiet phantom - just had to be careful not to short it out!

Your EV will probably work with less than 48V and the current requirement is minimal so try a 9V battery with a couple of 7.5K resistors to the +/- mic lines and see if it works. Up the voltage until it works well enough.

edit: it might be a good idea to put a couple of 50V caps to block the DC to your amp/mixer. If it doesn't have a phantom supply then it may not be rated for 50VDC input. A couple of 50V bipolar 10uF caps, one each to +ve and -ve lines.

edit^2: http://www.musiciansfriend.com/navig...tom+supply&st=
$20 and you're done

[dintymoore]

I have a small box made by Rolls that phantom powers 2 mics, it works fine.

[Original Burnedfingers]

Typically Phantom supplies are +48VDC. There are some instances where supplies run higher to power some on the non typical mics.

Phantom supplies can generally be anywhere from around 9 volts to 48.

One must also remember that Phantom supplies can also be negative DC as I have seen this on more than one occasion.

[patknk939]

Hi Iain. For the diy power kit, I guess I have to get the followings to build it -
1 male XLR connector for mic input
1 female XLR connector for mic output
3 9-V batteries (my EV mic operates on 24V-48V phantom)
2 7.5K resistors
2 50V bipolar capacitors.
However, I'm no expert in electronics, other than knowing how to solder, know what are resistors/capacitors. Would appreciate it if you could let me have more details, like simple schematics and how to connect, etc. Thanks.

[Iain McNeill]

Burnedfingers post already provided.
See the top half of his schematic. If you're using batteries, you probably don't need C9/R9 filter.

Your parts list is correct. Just double check polarity before you connect your mic - don't want to blow that!