Direct drive vs belt vs rim vs idler arm

Perhaps I missed it in the six previous pages of this thread, but there is an issue with belt drive suspended tables that is often overlooked. If the motor is mounted somewhere other than the subchassis along with the platter, then belt tension varies with suspension movements. There's no getting around this. Even if the belt has less stretch than rubber, the belt becomes part of the suspension. It's part of the suspension anyway in this case.

Suspensions are designed to compensate for acoustic impact on the table and they're tuned to a low frequency. When one sets up a suspended table it's made to bounce straight up/down. This straight bounce only occurs if you push on the suspension precisely, and in the right place usually equidistant from the springs. Hit the suspension in the "wrong" place and the perfect bounce becomes imperfect. Sound waves don't obey the rules dictated by a suspension and will hit the table in unfortunate ways.

I read a diatribe here about the Goldmund Studio and how the Delphi was so much better. It's true that the Goldmund DD's had an unfortunate suspension, but at least there was no belt involved. This was something that everyone came to realize and it became di rigueur to defeat the suspension.
Okay, we're not talking about the stock table any longer, but a Goldmund thus modified was far superior to a forgiving Delphi with its mushy sticky mat and speed variations. Even without the suspension defeated it was a more precise deck capable of extracting more information. The methacrylate platter was a prototype for platters/mats that are designed for physical properties compatible with vinyl.

It's no coincidence that Japanese statement decks of the late '70s early '80s were virtually all direct drive. When the CD was introduced in '80 they were phased out. The "superiority" of belt drive was sold to the public because that was the only option for a small manufacturer. They didn't have the technology or the motors to duplicate the Japanese decks, so they did what they could.

Belt drive has come a long way and some are much better than those offered in the '80s. Now, well into the resurgence we come full circle. Before '90 VPI had the HW19 and the TNT was just introduced. Now their top deck is Classic Direct, go figure.

Lewm, Peterayer,
I believe the 30/12 was introduced sometime near the beginning of this century and is example of what I meant by "having come a long way".
Sota on the other hand, like Oracle, seem to have their heads buried in the sand. My apologies if these have been redesigned, but you simply can't have a suspension, especially a bouncy one, and a fixed motor not moving with that suspension, without serious consequences. They might work pretty good until the suspension is excited, then speed variations and/or sideways forces on the suspended parts wreck havoc.

When I was a high end "turntable guy" I was always amazed by some people's inability to hear speed variations. This can be learned just like perfect pitch is now taught in music schools. It can be a two edged sword though, you might not like what you hear from your rig.

The Sota Sapphires were a mess. The motor was fixed to the plinth and a heavy subchassis/platter hung from the same plinth made out of 1/2" MDF. The three feet that support the whole affair were also attached to that plinth. The belt was replaced (90's ?) by an even flimsier one that insures poor speed stability. The subchassis was made of 1/2" MDF with a lead sheet laid on, and weight blocks on the corners except the arm area that had a reservoir for lead shot.

I still have an old Sapphire I took in trade. It sits in a corner looking pretty. I never could listen to it for more than a short while. I started to redesign it, but the subchassis is warped and azimuth is crazy. I like the platter and I'm thinking of a more extensive redesign with a metal chassis and Verus motor w/o suspension.
It's my understanding that Sota is basically the same today, except the Cosmos which has the motor mounted on the subchassis. I'm no longer familiar with Sota top models, but I imagine it could be looked up. Sota was always very secretive about their designs. They seem to be the only company to disallow their info in the VE database. Wonder why?

Regards,