I've had more surprises since my last post. While checking things out, I noticed I had all the tonearm wires backward on the RCA sockets on the back of the plinth. I had to move the plinth/chassis assembly around to get to it for soldering (not an easy task with the rubber balls I'm using for feet). Once done, I put the whole thing back in place. First thing I noticed was that the motor hum was barely noticeable now! I am perplexed! The only thing I can think that could have been effected is the power cord could have been caught on the motor and was dis-lodged when I moved everything. Nothing else has changed. Now, when I leave the motor on but don't engage the platter, I hear little difference between the stylus sitting on the record or lifted off. I may never know for sure what happened, but all is well now. No more nasty mechanical hum. Electrical hum changes a lot according to how the IC wires are positioned behind the equipment console. The wires are 10 feet long Monster Cable Interlink 400 MkII. I really need shorter ones for this.While playing around with everything, I installed my old Grado Black and was pleasantly surprised to find no more electrical hum than the Shure M91E had. Very cool! I like the Grado's sound better. I never cease to be amazed at how musical the primitive AR-XA arm can sound.
At this point, I have no complaints. Until the Black Widow arrives, this will do me just fine.
Dave