Hi. I just bought a VIBE Alpha II HC Subwoofer which I connected to my Yamaha RX-V1400RDS AV Receiver Amp via an unbalanced RCA to RCA lead. All was fine and I was pretty impressed with it. Then, a couple of weeks later, started a hum. It's really quite loud, so I got searching on the subwoofer forum and heard it might be an earth loop problem. The guy in work mentioned that if I disconnect my earth at the plug and the hum goes - it's earth loop. I did and it is. It's re-connected now - please don't flame me! Anyways, my reconnected sub still hums and I'm still looking for a solution. The two solutions I've read most are Series capacitor in a break in the RCA to RCA shielding, to break the loop and drain the RF interference A ground loop isolator in with the RCA to RCA I'm not keen on the first. Am not happy about cutting through the shielding on beautifully crafted cables to solder a cap in. The isolator solution seems reasonibly attractive, but I have heard they are expensive. Well the ones I'm seeing on Ebay aren't. My questions are 1) Will £10ish isolators from Ebay do the job or will they degrade the fidelity badly? 2) Are there other solutions I don't know about ( pulling the plug partially out at one end leads to a very loud hum btw ) 3) There must be an underlying reason why some mains sockets lead to this and others don't - is there a way of correcting the mains earth which currently goes down to my incoming supply shielding and water pipes ? Sorry this has been so long - thanks for reading this far!