Ground Loop Problem?

[logicG5]

Hey Im using a G5 with a MAudio Mobile Pre USB Audio Interface.

The Interface has 1/" and XLR inputs

If I plug my Triton into the 1/4 " in outs i g et ground loop buzz.

If i go through a direct box lifting the ground but still using the 1/4" inputs i do not loose the buzz.

Now if i go through the DI box and use the XLR output and the XLR input on the interface i get no buzz.

I have already tried differnt cables ect. Any suggestion to why i get buzz with the 1/4" but not the XLR and how i can get it to go Bye Bye using the 1/4"


Thank for any help.

[paully]

...If I plug my Triton into the 1/4 " in outs i g et ground loop buzz...

I hope this is a typo, but it implies that you're plugging the interface into a Triton 'input'. Except for midi applications (different format, cable type), that's a no-no.

... Im using a G5 with a MAudio Mobile Pre USB Audio Interface...

M-Audio uses 'combo' jacks on some units; a combination of XLR and 1/4" in the same package. Over time, the ground has a tendency to loose contact with the inserted input plug. Whether it's corrosion, dirt or just weak construction, ground hums will start happening. Try a little spray cleaner on the input plug, working it in and out of the combo jack's 1/4" hole. Same for any 'line' input jacks. 'Line ins' are probably the jacks that you should be using anyway. Why not try the SPDIF (digital) output directly into the interface. That's really the best option.

Paul

[Mixermend]

You are quite correct in thinking that you have some form of ground loop - and you have proved this to be the case with your DI Box XLR connection - which solved the problem......

The DI Box transformer has given you isolation between the computer and anything connected - and is the correct method to cure the problem.

In this instance no spray of any sort would do the trick!

It is very common to have this sort of interface problem with computers - especially lap tops, which are being used for recording purposes and also play out use by DJ's.

In the UK and Europe suitable Isolation transformers are available from:

www.orchid-electronics.co.uk

[paully]

Originally Posted by Mixermend

In this instance no spray of any sort would do the trick!
[/url]

>>>>>>>>>>>>>>
Open a ground anywhere in the link and you're suscepible to hum. I took a look at the unit after posting, and it doesn't have combo jacks. My M-Audio card does, and spray is exactly what was needed to make a solid ground via 1/4" inputs.
There's no guarantee that it's a ground loop, as to me his tests indicate an open ground inside the sound card on the 1/4" side. BTW, regular spraying is part of maintainance for any studio to assure proper contacts. Mabee logicG5 can post back what he found. If he plugs another unit into the sound card with no hum, then it's a loop. If hum is there, it's back to M-Audio for a checkup.

Paul

[Wavebourn]

What type of transformers may you profies recommend for from 16 Hz to 20 Khz on 10 KOhm 1:1?
I tried Altec-Lansing plugins, they work well from 10 Hz to 15 KHz only.

[brianroth]

Originally Posted by Wavebourn

What type of transformers may you profies recommend for from 16 Hz to 20 Khz on 10 KOhm 1:1?
I tried Altec-Lansing plugins, they work well from 10 Hz to 15 KHz only.

Look at Jensen and Cinemag.

Bri

[Wavebourn]

Originally Posted by brianroth

Look at Jensen and Cinemag.

Bri

Thanks. Why them?

[paully]

In the case of Jensen, full frequency response and high quality. A benchmark brand for many years.

******//www.jensen-transformers.com/apps_sc.html

Paul

[brianroth]

And Cinemag is a good alternative at a lower price point than a Jensen. Interestingly, Jensen transformers were once fabricated in the Reichenbach's factory back in the 1970's.

Bri