Halcro, you have done a fantastic job bringing us up to speed on this and also leading the way on trying alternative ideas on your Raven. However I must pull you up on a couple of comments on DD
"The differences between the two drive types I believe, has to do more with the speed of any correction applied once a deviation is detected?
In this.....a belt or thread drive is at a severe disadvantage.
The DD motor....usually with a lot more torque than that of a belt/thread drive....and being directly connected to the platter.....can correct deviations in micro-seconds theoretically inaudible to the human ear."
Thread drives do not self correct as DD's do.
Didn't your mother tell you 2 wrongs don't make a right ? You could argue a DD is twice as bad as a thread drive. One assumes if there is a time slippage and it is a one off why stuff the next few seconds of music trying to catch up ?
Then there is the correction of the correction when the DD overshoots on correction.... as my learned engineer tells me, nothing wrong with DD's they are only a little bit out all of the time.
"The DD motor....usually with a lot more torque than that of a belt/thread drive"
This is a presumption, I'm not sure it is correct. I'm not sure how many DD's could spin my 20kg plus platter up to speed in less than one revolution as does the AC motor on my thread drive.
But to balance the argument I still lust after an SP10mkIII for a second deck.