I suspect that some of the improvement I and others have found using versions of the outboard power supply for the GT 2000 is that transformer vibration is now removed from the plinth of the turntable. Conjecture on my part but feasible.
The GT 2000 series did not come standard with the external power supply but it was designed into the basic GT 2000 model to be purchased as one of the many available options. Any discussion about a GT 2000 needs to outline whether any of the options are being utilised because all of them will in some way affect the sound of the turntable.
The GT 2000 does not deserve to be omitted from the list of the multiple Japanese Uber Direct Drive turntables. Fully optioned the standard black GT 2000 had an external power supply, a 40 pound platter, vacuum hold down and spring suspension weighing a total of around 120 pounds. That really is the full fledged realisation of the GT 2000 series design concept. How anyone could leave it out of a list of the best Japanese Direct Drives boils down to lack of understanding/prejudice.
There is a misconception on the internet that the GT 2000 series utilised a ball in the bearing well. That is completley untrue. The contact point of the spindle was radiused (ala Linn Sondek). Also Liquid Audio reviewed a GT 2000 and reported it to have bearing play. Mike noted when he inspected the bearing closer that the thrust pad, (the contact patch for the spindle) had a crack which almost split the thrust pad in half. That ’bearing play/slack’ he found is in no way representative of a properly treated GT 2000 and is evidence that the turntable he was examining had been dropped with some force whilst the removable platter was in situ. Thus his sonic assessment of that particular GT 2000 is dubious.