Ill check all this out and replace as requested but its not "humming" and its not a sputtering low frequency.. its low end feedback, steady and long. Sounds exactlly the same as if you put a bass guitar in front of a bass amp plugged in and turned up. Its for sure feedback, im positive of that.

just would like to add that you can play over the hum. Thanks

 Ok so when I plug the amp up and play a few chords its fine.... if I turn the bass up or hit a power chord (G does it everytime) it starts sounding like really low toned feedback starts. It will not stop regardless of me unplugging the guitar from the amp or turning all the volumes down to 0.  This is a Silvertone 1464 SolidState 100. If someone could point me in the right direction Id appreciate it. Thanks!