New TT ideas please

While I agree with Doug's comments I also agree that they may be a bit oversimplified. As is often the case it's all about compromise. A stretchy belt does have all of the problems that Doug points out. But the flip side is that isolation from motor cogging and noise is also very important. For a given motor and platter combination there will be an ideal amount of coupling. And that ideal will vary widely.

The important factor is how much cogging the motor exhibits. When you start with a motor that has low cogging the motor can be more intimately coupled to the platter resulting in some major benefits. Motor isolation is only good if it solves a bigger problem than it creates. Much better to start with a motor that does not need isolation, or at least very little.

It's a similar compromise when it comes to torque. High torque is a very good thing when it is tightly coupled to the platter. It's the only effective method for eliminating the effects of stylus drag. The higher the torque the better. However, in the real world higher torque (good) almost always comes with higher cogging (bad). So as Thom pointed out the challenge is to find an ideal compromise. As with isolation using a motor with lower cogging moves the ideal torque higher with it's associated sonic benefits.

A good unsuspended table addresses the problem of floor and room vibration. It just does it differently than a suspended table. This is a common misconception. There is a big difference between "high mass" and "highly damped". Simply making a turntable heavy is useless and often makes resonance problems worse. A highly damped turntable is able to dissipate vibrational energy internally. So external vibrations are allowed to reach the turntable but are then dissipated once they arrive. The big difference is that energy emanating from within the turntable is also dissipated in a highly damped turntable. It is important to have a mechanism for dissipating internal energy as well as energy from external sources. Suspension has both beneficial and detrimental effects. And like motor isolation is only good when it solves a bigger problem than it creates. A highly damped turntable needs less isolation so in many (but not all) cases isolation ends up being detrimental. This is why most highly damped turntables tend to be unsuspended.

Chris

Doug This may a double post – I cannot see my prior response.

+++ Sorry for not explaining the Newton reference in my usual mind-numbing detail.+++

Actually you offered zero explanation and you still don't.

+++ It resulted from the suspension allowing plinth movements in reaction to cantilever excursions and arm movements. +++

Okaaaay. A couple of misconceptions here.

Cantilever excursions cannot make the plinth move. The plinth is hard coupled to the stand. In my case, the stand is on a concrete floor. So unless the tonearm has more mass than dear old earth, the plinth 'aint going nowhere'. Need to do some rethinking here Doug.

The LP rests on the platter, not the plinth. Relative movements between the plinth and platter/tonearm assembly are only relevant if they have sufficient energy to upset the tonearm/platter assembly. That would would require something like an hard thump on the rack; something that would send an unsuspended tables arm flying across the record.

Real movement of the platter + tonearm assembly is important. In real conditions, there is absolutely zero movement – the suspension is at rest (equilibrium). When sufficient energy is dump on the table to cause movement, a suspended turntable ensures said movement to be at a frequency that does not do harm. Unsuspended turntables feed all frequencies directly into the platter and tonearm. That will include all audible frequencies AND your tonearm/cart resonant frequency. Not nice.

Relative movement between tonearm and platter is important. Cantilever excursions will dump identical amounts of energy on tonearm platter interface on both suspended and not suspended tables. Any downward movement of the platter (which will be minute) on a suspended table is compensated by LESS upward movement of the tonearm. This is Newtons law. “For every action there is a EQUAL and opposite reaction.” Emphasis on equal.

A non-suspended turntables cantilever excursions effects the tonearm platter interface with EXACTLY as much energy as a suspended table. That is not black magic, but pure science. Due to the higher mass of the platter assembly, the energy dumped into it from a cantilever excursion translates into less movement. (again, no black magic but Newtons second law).

In other words, the energy is better managed by a suspended table. On a non suspended table the tonearm needs to deal with 100% of the energy, and being so much lighter than the platter assembly, will exhibit the maximum movement.

As for your friends comments, I can echo that coming from a unsuspended table to my Oracle. So my response would be to chuckle also – seems not everybody knows how to set up suspension (although I did find it straight forward)

BTW, I still have an unsuspended table. It sounds better on air bladders.

Kind Regards
Paul

Doug
To dismiss suspended turntables out of hand is in my opinion a bit like throwing the baby out with the bathwater.
The JEM Blue Pearl is reported to be a good contender for state of the art performance.
and YES it is a suspended design.
I changed from an older Oracle Delphi to a Scheu Premier 11 and although the Scheu had its strengths I preffered the Oracle in my system.
I now use Townsends new Rock mkV and can apply all of your'e friends comments against the Scheu and Oracle tts.
and the Rock is a high mass suspended design.
A well designed tt is a well designed tt
suspended or not
all the best
Terry

Pauly, while I agree with you that there are very well implemented suspended tables I think you have overstated a few things to make your point.

The platter is directly coupled to the plinth via the bearing, unless the bearing is of the magnetic/air type. The plinth on suspended tables are not directly coupled to the stand, but rather floating on the suspension. If there is sufficient drag on the platter during dynamic passages there actually could be a rotational twisting reaction on the platter/bearing/plinth as well as the drive. I do believe most higher quality suspended designs have addressed this to the point where you would probably not hear it.

As for thumping a non-suspended table and making the cartridge fly, I can tell you that that is much easier and more likely to happen with a suspended table. That is exactly the reason I moved from suspended a (Basis) to non-suspended (Galibier) table. It is not the first moment of impact that caused the stylus to jump. It was the second moment when the suspension jerked back to the steady-state position that the stylus left the groove because it wanted to keep going in the original direction of motion. Bodies in motion tend to stay in motion unless. . . yada, yada.

We can all look around and find good and bad implementations of both approaches. I don't think it is so easy to dismiss either when the implementation is well done. I still have a high regard for Basis tables but there are some things I would never try to do with any suspended table. Like adjusting VTA and AS while the stylus is in the groove. I realize this isn't important for everyone but it was for me. Lucky for me that I'm in a position that I don't have to have a suspended table.

I've gone steeply up a curve on this thread alone. I know there are differing views and nuances, but you lot seem to handle such things in a very gentlemanly fashion (apologies to any ladies).

Many dealers lambaste the web, but those are the ones that don't like an educated customer.

Many, many thanks to all here.

Cheers