08-18-13: LewmThis is misrepresenting the 927. Although its platter is only 5kg the 16" diameter and weight distribution results in inertia similar to much much heavier platters ( I think 50kg equivalent has been suggested ). This may be a good thing, attaining high inertia but keeping mass and hence energy storage within the platter low.
Mosin, Would you therefore dismiss any turntable with a light weight platter (and therefore a rather low moment of inertia) as a "contender", just on that basis alone? And if so, what is your cut-off point for "acceptable" inertia, in terms of platter mass?
The 927 appears to have a "heavy" platter compared to that of other well loved idlers, but not in the league with some of the monster belt-drive platters I have seen, e.g., the Walker lead platter.
The cutting lathes using the much vaunted Technics SP02 DD motor ( which in power and torque and poles is vastly superior to the SP10mk3 motor ) still used this flywheel effect as well with 60lb platters used in the cutting process despite the power and "servo" speed control.
Good turntable designs are very much a 'sum of the parts' - you cannot just ascribe a specific attribute such as what is the minimum platter mass required, because the answer will always be - that depends.... on the bearing, energy storage considerations, platter material, speed control etc etc
It's a bit like - I need to solve a problem, can I borrow Einsteins brain. It doesn't work. Why. His brain doesn't work without the cardiovascular system which you didn't specify in your request. Ok I got the rest now and it still doesn't work. Why. Because he likes a good walk and breakfast to get the juices flowing.