Feedback and phantom power!

[thetmg84]

This is my first post so be gentle with me!
Iv been using my pc with a line6 ux2 interface and ableton live lite to record guitars and vocals with no problems. I recently acquired some drum mics so me and my drummer friend went about setting everything to record.
All 7 drum mics went to a mixer and then into one input on the interface, my guitar went into another input on the interface so we could record guitar and drums on separate tracks  at the same time. We had a set of headphones each coming from a splitter in the headphone socket of the interface. I had the phantom power switch on the mixer as the 2 overhead mics needed it, as soon as the drums were hit an awful feedback type noise would occur through our headphones and would only go away after everything was unplugged. I thought it might have been the phantom power so I turned it off and we proceeded without overheads. Everything worked and we managed to record. 
The next day I thought I'd try again. I added a headphone amp to the headphone output so 3 of us could listen. The same noise occurred like before. removing the overheads and turning off the phantom power did not help this time either. I played back a recording from the previous day and that set the noise off again! I then removed the headphone amp and used only one set of headphones to listen to the recording and it was ok. By this point I had given up on recording drums so I tried the overhead mics straight into the interface and everything sounded fine. I'm very new to recording and maybe I'm making an obvious mistake. Could it be some dodgy cables? Too many headphones? The phantom power? The interface? the mixer? Or all of them! I'm really confused so any help is gratefully appreciated. 

[stainless]

Welcome to HRS

well, nothing like a good mystery!

correct me if I'm wrong- questions in red

you have  Line 6 UX2 and both inputs are connected to the stereo outputs of a mixer.  what kind of mixer? new? old? powered?... and how is it connected to the UX2?- XLR cables?, instrument cables (NOT SPEAKER CABLES?) balanced cable (TRS)?

you have 7 drum mics- 5 dynamic and 2 condensers

one guitar input

"as soon as the drums were hit an awful sound..."  can you explain this? are you slapping/punching the drums? is the sound a high pitch noise or lower freq solid tone?

phantom power - is the mixer supplying this? or the Line 6 can provide phantom power, is one 'on' and one 'off'?

where are the headphones plugged in?

mic cables- new? old?, home-made?

to confirm, you plugged the 2 condenser mics into the UX2 (with phantom power supplied)- and no rude noise- were you using the splitter for the headphones when you did this plugged into the same place?  same cables for the ccondenser mics that were used on the mixer?

[thetmg84]

Cheers for the reply.
 I set it up like this........
 Drum mics to Samson mpl 1502 mixer then tape out to instrument input on interface.
 Guitar amp mic'd into mic1 input of interface and headphones out of interface.
 Mixer outputs are 'main out' 'aux send' and 'tape out'
 Interface inputs are 'mic 1&2' 'instrument-normal and pad' and 'line inputs 1&2'
 Interface outputs are 'analog out 1/L & 2/R' and 'headphones'
 The noise was a lower freq solid tone, not really a feedback noise but i didnt know what else to call it!
 The mixer was supplying the phantom power.
 Mic cables are brand new.
 Iv just tried (someone else recommended i do so) going from the mixer 'tape out' to one of the 'line inputs' on the interface and going   from 'analog out' to my headphone amp and it seemed to work (fingers crossed). I will probably test it more at the weekend.
Thank you very much for your detailed reply, if the problem persists i will be back for more advice!

[stainless]

OK....

This is probably not an ideal mixer for recording....

but

so I'm gonna guess your dynamic mics are using XLR x  balanced 1/4" cables (look likes a stereo plug?  or  are these mics with attached cords an a TR 1/4" plug (like a guitar cord)?

as you only have 5 balanced inputs (that also phantom power)- you're condenser mics into  mixer channels 1 & 2, of your 5 remaining drum mics,  use 3, 4 & 5 for 3 of the dynamics, and 6 & 8 for the remaining 2...  Guitar in to 10- pan according to taste

using some balanced TRS cables, connect from the main outputs to the inputs on the Line 6, however the built in pre-amps on the UX2 is another level of 'gain', so I would be more inclined to set your main level on the mixer at 0 (unity) as well as the gain levels on the mixer inputs to 0, and all pads set to -10dB  as a starting point and starting with the levels on  Channels 1 & 2 on the UX2 all the way down and slowly bring up till the output in your recording software is between -18dB and -10db

Headphones- use the UX2 output

I believe this  will give you the best quality signal. I would leave the tape outputs strictly for going to  an analog piece of gear... always use balanced inputs/outputs when recording unless it's not an option (IMHO)

this should work

I'm guessing the rude noise was a grounding issue, possibly caused by the phantom power and it was finding a direct path to ground...

[thetmg84]

I'm using xlr cables and for the other 2 inputs I use xlr to 1/4" jack adaptors.
Iv been putting the condenser mics in 1 & 2 like you said.
Il try using the main out outputs from the mixer. My guitars going in one of the inputs on the interface so the mixer will only have one input to go into. The interface and software only allow 2 simultaneous inputs.
Il try everything you suggested and see what happens!
Thanks for your help

[stainless]

for recording, you'd have  better 'spatial' placement by running the guitar through the mixer and having a a stereo field, otherwise  the drums are mono and you could get by with far fewer mics (2 overheads and a kick might be all you'd need)

granted with the guitar in the mixes there can be no mistakes with you or the drummer and your still very limited... does the Line 6 have an aux input??? if so, try running  guitar through that (you may need a pre or some kind of pedal for some signal boost) but if your software will allow for an aux in on it's own track while using 1 & 2, that would be to your advantage

and I suppose if you're going for a very 'retro' sound your current approach would be fine 

let us know how things work out