My phantom powered MIC problems

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Mookie

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Hey everyone,

I have a couple of cheap MXL condenser mics that I am sure you are all familiar with. The problem is that when I plug them in to my Yamaha MG16/6 mixer and activate the phantom power to use them I get this loud hum that runs all the way through the mix through my EMU 0404 and into the recording software. I have shut down everything in the house and can`t find the source anywhere. Is there anything I should be doing? I could really use some help with this.

Thanks

Mook
 
If you shut off other stuff in the house, then you might have a problem in the mixer. Is it still noisey if you turn down the volume on the mixer? Is the pre turned way up, or down? Constant noise, or does it fluctuate at all?
 
The hum is directly controlled by the main out. If I turn up the either the channel fader or the main out I get an increase in the volume of the hum.

Thanks

Mook
 
Forgive a potentially insulting question, but you are using XLR-to-XLR cables, yes?
 
Is this a new problem, or has it always happened? Do you have other cables to try? Is it plugged into a surge protector? Try a different wall outlet if possible.
 
it appears to me to be recent. I know that may sound strange but I am really just now getting into the home recording scene and I have upgraded considerably over the last month. New software, 96/24 ASIO drivers and new KRK monitors. perhaps all of this was buried and I never noticed but It has become a real pain.
 
Would it make sense to go borrow a DI box with Phantom power and plug the mic into that and eliminate the on board PP?
 
Mookie said:
Would it make sense to go borrow a DI box with Phantom power and plug the mic into that and eliminate the on board PP?
Click to expand...
If you can, try that. It might help pinpoint the trouble. Can you try a different wall outlet, or surge protector? May not make a diff, but you never know....
 
I`ll give you a rundown of what I have and what I have done so far. As I said earlier the Mixer is a yamaha 16/6mx. all the power for the entire studio is provided by 3 furman power conditioners the line voltage never seems to fluctuate beyond 118 and 120 volts. The monitors are passive krk ST6s and they are powered by a yamaha p 2200 power amp. The guitar rack is also power conditioned as is the PC.

I think that you may have a point with regard to the phantom power on the board picking up a ground loop. There is no other noise when using passive microphones. I have run some extention cable to another outlet in another room in the house and have the same problem.

I am going to try a DI box with phantom power and see if it corrects with this. At least if I isolate the problem I can start to form a plan for fixing it.

thanks DOGMAN again for all your Ideas


Peace

Mook
 
Mookie said:
I`ll give you a rundown of what I have and what I have done so far. As I said earlier the Mixer is a yamaha 16/6mx. all the power for the entire studio is provided by 3 furman power conditioners the line voltage never seems to fluctuate beyond 118 and 120 volts. The monitors are passive krk ST6s and they are powered by a yamaha p 2200 power amp. The guitar rack is also power conditioned as is the PC.

I think that you may have a point with regard to the phantom power on the board picking up a ground loop. There is no other noise when using passive microphones. I have run some extention cable to another outlet in another room in the house and have the same problem.

I am going to try a DI box with phantom power and see if it corrects with this. At least if I isolate the problem I can start to form a plan for fixing it.

thanks DOGMAN again for all your Ideas


Peace

Mook
Click to expand...

Good luck dude.
Ed
 
just a thought

I know it might be a longshot but I have a MXL 990 that was causing a bad hum like you described. I loosened the body and the windscreen just a little and it stopped. It didn't hum until the phantom power was on either. I guess there was a ground problem in the mic itself. You never said what model MXL mics you have.
good luck
 
ch2os7 may have a good point. Especially since it is the same brand of mic he had the same problem with, and especially since phantom power is designed specifically to defeat that type of noise. Seems logical, if there is a hum when using phantom power, which is supposed to prevent hum, then there may be a problem with the phantom power or the mic itself.
 
Thanks for all the input. I went ahead a bought a Rolls phantom power supply today to test the theory that It was either the mic or the mixer. The phantom power supply I bought worked flawlessly with no noise what so ever. When I activate the onboard 48 volt PP lots of hum was present. I have spoken to Yamaha and they think it may be the AC power supply for the mixer itself, or even the filters and IC`s that comprise the phantom power in the console. In any case I am back to tracking with the condensers but I will try the loosening of the screen as suggested. Incindentally the MXL`s are 603 S Mogami and a 990. Both sound great and work very well for my applications.



Thanks once again


Mook
 
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