Maxxarcade,
I've read this post today and am wondering if the hum problem has been resolved. During my review of the pictures and the text, a nagging thought has come to me pertaining to chassis grounding of the solid wire ground bus wires. There does not appear to be a solid connection between the bus and the chassis which means that the solid wire ground bus may be floating, i.e. isolated from the chassis. This could be the problem which is causing the hum you are experiencing. The inside of the chassis has been beautifully painted "Chevy Orange" which puts an insulating coat on top of the aluminum (or steel) chassis and may be the reason for such "float". To determine this, scratch a small area (1/4" X 1/4" or so) of the paint down to bare metal on the inside of the chassis, verify the power cord is disconnected and then with your DMM or VOM check resistance between the chassis and the wire ground bus. A high Ohm reading would indicate a "floating" ground bus whereas a near zero reading would indicate that the ground bus is suitably grounded to the chassis. In the event you determine the grounding bus is "floating", connect a wire between the bus and the scratched bare metal chassis point and power up the amp to see if the hum has gone away.
Bill
