Noise problems!

Hey dudes! I have a serious project coming and i need to record few things at home, so I noticed that a electrical buzz noise is on the background of the sound. Few days ago I bought a ground loop isolator, but it seems that it makes more problems instead of fixing. I contacted the company where i bought my isolator but they were bummed I they didn't know what to tell me. So I would appreciate if you have a solution for my problem.
Info plus:
-The noise is off, when laptop (where MV is running) is on battery mode
- My mixer (Ecler Nuo 2.0) has a rec out (RCA) which is connected with another PC where all is recorded with Audacity
thx
Info plus:
-The noise is off, when laptop (where MV is running) is on battery mode
- My mixer (Ecler Nuo 2.0) has a rec out (RCA) which is connected with another PC where all is recorded with Audacity
thx