Micro SX-8000 II or SZ-1

The system seems to have eaten the post on equivalent mass, so I'll do another.

The idea is analogous to the method of calculating equivalent mass for tonearms and the calculation is the same: divide the moment of inertia by the square of the radius of action, the result being an equivalent mass.

Using a standard radius of action of 150mm, the equivalent mass of the flywheel arrangement for the Micro Seiki is 2.58 kg.m^2 / (0.15m)^2 giving 115 kg.

Note that due to distribution of mass, a TT platter would have to be about 200 kg to achieve this equivalent mass.


Mark Kelly

Lewm, of course you need to see both units in person to have a better decision-bases. Nevertheless the solid buttons of the RY-5500 II and their haptics are a statement of High-Quality engineering and machine building I do not see at the SZ-1m so far.

The link Pcosta provided gives a very good picture of the unit and of the buttons. What matters more than taste of design is the in-built fly-wheel concept and the air bearing of the SZ-1m which T-Bone has described. Maybe I should look for an extra fly-wheel unit for the 8000.

Mark,
Thanks for posting. I had not seen your first post when I wrote and i had not looked at the VK page linked. I was noting the mass moment of inertia of a solid with zero angular velocity (which is the way all Japanese TT specs historically have shown their mass moment of inertia spec - which if I'm reading your idea correctly, reconciles with your recalc above because the coefficient of the square of the gearing is... 1.

When I think about it, when my Exclusive P3's capacitors went, it was probably going something like 750rpm too (until I shut it down). If I could harness that and use the spindle, I could have gotten something like 1000 tons/cm^2 (a lot more weight and much bigger r^2).

I will go away and digest some of this.

As to the Saskia, I had previously read the 'effective mass of 200lbs' bit on the OMA homepage, but as there is no other information, and I have not seen any other info on the table elsewhere, it is difficult for those of us less in the know to understand how that comes about. I will assume (and we all know what people say about that), that the

tightly controlled external rotor motor when combined with the turntable's heavy platter results in an effective mass of well over two hundred pounds

means that "because it is rim drive not belt drive, when combined with a platter of X mass, we get effective mass of X+Y mass." There is so little information on the OMA page that anyone with a modicum of info could probably see where I am wrong on this too, but I couldn't quickly find any info months ago when I first looked.

T Bone

The equivalent mass given by OMA is calculated according to the method I used.

It's not the mass of a platter equivalent to the total inertia of the system, this would be even higher (around 400 lbs). IIRC Win decided to use the more conservative figure - he's a big believer in understating and over-achieving.

Mark Kelly

Mark, I understand the calculation but do not understand (from reading the webpage) where the 'gearing coefficient' comes from - higher speed flywheel providing gearing vs 33.3? rim-weighted platter increasing effective rotational inertia when compared to solid mass?