Just thought I'd update you guys, the amp is finally fixed and working as it should. I ended up totally rewiring the amp and converted it to a TMB circuit that was recommended here
The more I played the original amp I found it had an odd sounding wooshy distortion to it, hard to explain unless you heard it, add in the hum and I figured the TMB design would cure that.
When I played the new TMB it sounded horrible, the clean channel was super distorted in the same wooshy sound as before, something was definitely not right and I still had the low hum. Since I had already changed literally everything in the amp, I started to wonder if the output transformer could be failing..Some forum posts I found online seem to describe similar sounds to a failing output transformer. I was using an old Hammond Organ OT so I figured why not order one and try it, had nothing to loose.
Well, that was the problem all along!! Hum is gone, all channels sound great, wooshy distortion is long gone!!
The amp is one of the quietest I have at idle, forgot it was on the other day! I've also finally heard the sound the 18 Watt is supposed to make..finally it's done!
Just thought I'd pass the fix along in case it can help someone else with a faulty OT. Thanks for all your help guys!