60 Hz Hum

I just finished the http://www.aussieamplifiers.com N-channel, and it has a hum. I measured it with a hz meter and it is 60hz.
When I short the input it stops humming. Not sure if that means anything but that is how we tracked down ground loops in car audio. The pre amp is a Adcom GTP-600. It does not hum when connected to the GFA-5500. I tried unhooking the chassis ground but that didn't stop it. Any ideas on how to stop it?

Thanks in advance,
Chad
 
The hum could be due to your power supply layout. I found that using separate rectifiers for the positive and negative supply rails helps to minimize the chances of a loop. Each secondary winding should feed a bridge rectifier, which are then connected to the power supply capacitors. The ground point should be made at the capacitors and all ground leads connected at this point. +/- Connections should also be made at the capacitor terminals not at the rectifiers.

Hope this helps.
 
Thank you all for your help. I found the cause of the hum. Believe it or not it wasn't the amp. It was my X-10 signal bridge in my main breaker panel. It was on the same circiut that the amp was plugged into. When I changed plugs the hum stopped. So I plugged the amp back in and moved the X-10 to another ciruit. Now my amp works fine and so does my home automation system.

Chad