Two companies made the Buzzed birds, correct?
Only 5 batteries to power his carbon fiber bird
I have a theory as to why his tone became as artificial & brittle. I believe that he adjusted his tone for what he heard, which was confounded by the fact he too was going deaf. All those years of damage to your hearing would have effect the way you hear things vs how they really sound.
That's why I feel his best tone was from his P bass & Fenderbirds.