Success!!! I removed all the hum and static from the amp. I had the amp running without the box and probed around for sensitive areas. Using an antenna wire I discovered that the front chassis plate near the input was the source. If I touched the wire to the chassis plate near the input the static signal was much much worse. Further, touching the antenna wire to the shield terminal on the input was like listening to a radio at loud volumes. It was one station in particular. Looking at the mid-scoop circuit I found a loop antenna from one of the small capacitors. I removed that and wired it to the switch instead of the input and 90% of the noise went away. Secondly, I added an additional ground wire from the shield on the input to terminal 18 to make sure the chassis near the input was well grounded, and voila.... the noise was gone. I know my house ground is not that great but this makes me feel much better.
