Help!!!A Hissing/Hum Sound When Using The Avalon 737

[WRCA]

hey i wonder if you guys can help me out, basically ive purchased a Avalon vt-737 sp,, now when i connected my mic to this i can hear a hissing sound in the background. I read the manual it said if your your getting this sorta sounds remove the ground link which i did and i'm still getting ths sound. I then connected the mic with the same cables to my other pre a envoice mk11 and there was no hissing sound. Do you think theres a fault with the avalon ? i thought it might have been something wrong with my cables but they seem to work fine with the mk11, i'm really confused,, i'd appreciate the advice, I also connected the pre to different sockets etc it made no different, and also made sure it was not tangled with no other wires, but that annoying hissin/humming sound still comes. And when i touched (not moved) some of the buttons on the avaoon it made the the hissing sound louder like a sound u'd get when your tv aerial signal is playing up.

[7 Hz]

Your unit is broken. There is quite possably something wrong with one of the power smoothing caps. Unplug it straight away, do NOT use it, send it to to your local trusted repair person to be fixed.

[WRCA]

thanks very much mate, i'll be on to the phone to my dealer soon as possible