So I've installed my new Yamaha 640RDS amp. Everything hooked up fine, and sounds great. Just one problem: When I went to hook up the HF channel on my REL Quake, the sub started humming. Here's the way it's set up: - Quake hooked up to standard sub-woofer output via RCA for LF - HF (Neutrik connector) plugs into the sub - I've hooked up the other end of the HF cable to the Speaker B output for the main speakers, so that I can turn it on and off at will However, the subwoofer starts humming the moment I plug in the Neutrik connector. Even when the other end of the cable is NOT PLUGGED into the amp, the sub still hums as soon as I plug in the Neutrik cable. I obviously thought I wired the Neutrik plug incorrectly, but then I borrowed one from a mate who has been using his cable succesfully on an MJ Accoustics sub, without any humming. Can it be that I have a defective amp? Or does REL use a different wiring-setup than some of the other manufacturers? Has anybody else hooked up their Quakes through the Neutrik HF connector? Any help is welcomed!