Audio Technica 825 Stereo Mic - Phantom Power Issues

[Dave]

Hi All,

I've just rented an Audio Technica 825 stereo mic to experiment with for DSLR ambience.

It's got the 5 pin connector into the mic with a split XLR Y cable into my Tascam HD-P2. I'm getting a bacon frying sound with phantom power engaged on the HD-P2 (and the same issue when using a new Fostex DC-R302). The crackling static is present yet intermittent, but is definitely worsened when the mic cable is moved even slightly.

This is the case when either recorder is being powered by internal batteries or with an external AC power adaptor. However, when I power the mic itself with an internal AA battery and forgo phantom from the recorder, the cracking bacon static disappears and the mic runs as expected - clean and normal.

Is this mic wired differently than normal? I'm using the proper AT cable for the mic.

Lastly, do I need to power each half of the mic (XLR right and left) separately with phantom? I do get signal on both right and left with just the right being fed phantom, but not sure if this is correct.

I guess I can just use AA power in the mic itself, but would like to get a handle on what causes the frying bacon sound.

Thanks for your kind tips and have a good evening.

All the best,

Dave

P.S. I applied phantom from both recorders to a Rode shotgun and had no issues.

[Eric Toline]

Surprised you didn't try with phantom on both channels. Try it and report back.

Eric

[Angelo Waldron]

Remove battery from mic when using Phantom Power. It's typical with stereo mics to need to power both channels with Phantom even it you are just using one channel.

[studiomprd]

...and when all else fails: RTFM

and when all else fails: RTFM

[Dave]

Hi Eric,

Yes, applied phantom on both channels - audio still the same as when applying phantom to only right channel. The sound of my vocal test itself is fine but it is always accompanied with the bacon frying static sizzle when using phantom - as I mentioned, all is good when only using a battery in the mic.

When using phantom from recorder I did not have a battery in the mic.

Will keep experimenting. Thanks for your tips :-)

Cheers,

Dave

[rofin]

Dave, based on that the mic works when AA powered but not from either of two machines and that the crackling is 'worsened when the mic cable is moved even slightly', I'm suspicious of the screen connections in the cable.

Being phantom powered, the screen is the return for the current.

Try more localised, gentle tweaking of the cable to see if you can narrow it down to a particular spot or connector.

I understand that it is a rental kit so you might not want to 'disassemble' it, but if poss, unscrew the xlrs and have a look for broken screen or indeed frayed screen with strands touching where they shouldn't.

Rob

[studiomprd]

" it is a rental kit "

call them...

[Dave]

Hi Rob,

I think you've solved it for me. I gently wiggled the cable at all the points along the length and the static appears when I move the the first foot at the mixer end and also the first foot or so at the mic end - probably where most of the strain takes place. Everything in between is quiet.

I'll unscrew the XLRs and see about frayed strands touching there too. Since this 5 pin stereo cable is so specialized I'll be sure to get a new one and a backup spare. Thanks for your practical advice Rob.

Thanks too Senator.... you called it right.... RTFM.... or better still..... RTMF.... cheers!

Dave