Came across this Post by another Contributor in the past:-
Don't get me wrong, I totally do not underestimate the importance of the speed control architecture. Motors of this type will not be speed stable under load without it. This was a second revolution (no pun intended) in the late 70s, early 80s. The big Japanese companies came up with far better control systems on their later decks (to go with the better motors) that all but eliminated the over/undershoot issues that have been attributed to DD control systems. JVC famously (and probably most successfully) came up with a double bi-directional servo that was also used in the Yamaha GT-2000 series TTs (Yamaha also used one of JVCs 4 pole coreless motors AND a 6kg platter for even smoother operation). Kenwood for the L07-D (and probably later coreless motored DDs like the KP-990 and KP-9010) had a very sophisticated double nested PLL design that was relatively "soft" and also had a 5 or 6Kg platter for inertia.
Seems the DQX-1000 uses a JVC motor...prior to their big switch to coreless. Try to hear a TT with a coreless JVC motor and bi-directional servo if you can...
You are wrong, the "boom" in coreless was in the late 70s and early 80s when digital controllers as such didn't even exist!! It was not cheap to implement a good controller at that time (at least the first time it was developed...it gets subsequently cheaper the more you use it...although the one in the TT101 was never simple or cheap). There is a rediscovery of that technology going on in the last few years but there was about a 30 year drought in its use in new TTs.
