Better Music through ground loop isolators

I don't own a CD player. Nor do I have a radio or a TV. I simply have a Mac Mini with an EyeTV Hybrid (of course) and iTunes. That, however, is hooked up to an amplifier, to which some nice and old speaker boxes are attached. I got these boxes from my dad, together with an ancient tube radio, and although they're tiny, they sound terrific.

This could be a great set-up, if it wasn't for ground loops. Ground loops, essentially, are the source of the humming sound that you get in your speakers when the devices attached to your amp are "out of phase". It apparently has something to do with AC (alternating current, like it comes from wall outlets) being rectified to become DC (direct current, i.e. no-longer alternating, like batteries), and depends on which phase gets turned into "+" and which into "-" in the process. If this doesn't match, you get a humming noise in your speaker.

The cheap solution would be to plug in the power plug the other way round. The problem with computers these days (and particularly with a Mac Mini with its small form factor and only four USB ports and one FireWire port for extensibility), is that one quickly has about two dozen devices attached to the Mac, most of which have their own power supplies and may be plugged in the wrong way.

The solution is to go to some electric components shop like Conrad here in Germany (I guess Fry's would be a rough equivalent in the US), or to a car electric parts dealer: There you can get a "ground loop isolator" ("Mantelstrom-Filter"). You simply plug it between the Mac and the amplifier, close to the amp, and it will take the buzzing sound out of it.

My iTunes never sounded better. I can turn up the amp, and no noise, no humming, just music. Fantastic.

Thanks to this great tip goes out to our resident audio guru Andy. It's great to work with people like that.

Reader Comments: (RSS Feed)

No comments yet

Or E-Mail Uli privately.