Ground Loops

[Steve Zorilow]

Yup, like I said, a good quality audio transformer is required. Those cheap ground loop isolator can't offer a good quality transformer for that price, and yes (lol) the worst one can be "microphonic" as well. Some are better than other.

A good passive DI is design to work with "stage" & Loudspeaker vibrations. So they're better choice along with good quality stereo Hum/Ground loop isolator available at your Pro-Audio store.

Something like
http://www.bluestarmusic.com/Ebtech-...Out-P1131.aspx
would be a smart choice. There's also some without level Shifter.
http://www.frontendaudio.com/Ebtech-...tor-p/7028.htm

HTH

[looneygeorge]

What are these for ?

[Steve Zorilow]

In some situation, when you connect your Audio Card to a mixer or PA, your may hear some Hum or High-Pitched & unpleasant noise. This is due to a really common problem called Ground Loop. The above break the loop and solve the issue, the safe way.

[looneygeorge]

but what if you dont have one of those and the problem occurs? can you solve it quickly on location?

[Steve Zorilow]

Me yes because I have over 20 years of PA tech background and always carry extra wire, gear, soldering guns & plugs (or at least a good pair of cutter + electric tape), but others may need to deal with the offending noise if they don't have any of the above solution on hand, or know someone on place to fix (help to fix) it.