After about 10 days, the audible rumble/drone is largely gone, leaving us with just 30Hz idler noise, the 9Hz tonearm resonance, cars passing by, the neighbors going at it, deer in the backyard, etc. etc. Bear in mind, this is just the vibrations from the motor that are transferred to the deck, not the actual groove noise. In terms of actual record playing, I'd say it's about as quiet as any decent belt or direct drive now. Not bad for an idler-drive changer from 1965!
View attachment 2101659
One thing that is concerning me a bit more, though, is the fact that my eBay plinth is sagging in the front left-hand corner, where the motor is. I thought it was just a worn out spring, but nope! The pressboard mounting is visibly deformed, presumably from the weight of the motor pressing down on it all these years. Guess I'll have to find a new plinth or find a way to reinforce this one, if I want it to be 100% perfect.