Eliminating Ground Loop Hum

[MikeS]

I recently bought a Morley Wah and in the packaging was a mini catalog. Anyway, within there are a few pages devoted to a company by the name of Ebtech, and they've got a couple products that claim to eliminate ground loop hum. One is a rack mount unit and another simply plugs into the wall between the amp head and the outlet.

I only ask because we have horrible noise in our studio, which, oddly enough, is ten times worse after dark. I'm trouble shooting here, and wondering if these ground loop hum "eliminators" actually work as advertised.