Direct Drive Rumble

I remember back in the 70s when direct drive was an upgrade from belt drive in every manufacturers lineup. This was before Linn, SOTA, etc. took over the world of turntables. Conventional wisdom has it that direct drives couldn't compete because they were noisier than belts. The theory advanced at the time and still held by many was that the belt mitigated the influence of motor vibration on the whole system. What I recall, however, is that there were consistently lower rumble figures for the DD tables over the numbers posted by the belt drive units. Is there another measurement besides rumble to indicate motor vibration and its deleterious effects?
Isn't rumble referring to the bearing effects (the quality of the bearing design and manufacture)? Wow and flutter are the primary parameters affected by belt vs DD.
DD TTs do have less rumble (theoretically) because they are free of the assymetrical side force on the main bearing found in (most) belt drive TTs.

Therefore, assuming high quality bearing design and proper lubrication DDs are essentially free from rumble but can suffer from a kind of 'flutter' produced by the motor pulses. The better ones use a feedback system (e.g. Micro Seiki) or a clock (quartz) regulator like the Technics, JVC, and Goldmund Studietto to name a few.

You can find a lot of great info on DDs at:

Thank you, gentleman. The bearing issue had never before come to my attention. It would seem, from what you are saying, that direct drive has the greatest upside potential since it will experience less rumble effect and no worse than equal wow and flutter.
I started another thread a while ago about the suspected superiority of DD and the arguments surged back and forth for weeks resulting in nothing conclusive.
Near the end of that period, I had occassion to visit Chris Brady of Teres turntables at his home and witness the unveiling of his new DD table. It was clearly superior to his best BD which was used for comparison. There was more of a sense of drive and attack in the DD. The BD by comparison sounded "lazy". Chris is now convinced that DD has a greater potential for playback. And so am I.
I hope there will be a new generation of DDs in the future. It would be interesting to see them made with an inverted platter bearing. Is the Teres made that way?
Direct drive or die.
If you have been following the threads over on Vinyl Asylum regarding idler-wheel turntables you will know that the next few months should see a new DC motor drop-in replacement for many of the idler-wheel tables of yesteryear. Removing the motor vibration from idler-wheel tables will give those TTs a major sonic improvement. And could spur the development of totally new idler-wheel tables.

Teres is just one of several companies coming out with new DD turntables. It looks like belt drive TTs are going to be caught between an upsurgence of direct drive and idler-wheel tables. That has got to be good for vinyl lovers.
It will only be good for the vinyl lovers who can afford them.
The rest of us will have to find ways to make do with yesteryear's product. Of course, that may only apply to DD. Do you have any idea what the retrofitted Idler motor will cost?
Hi Macrojack,

"It will only be good for the vinyl lovers who can afford them."

I disagree. Everytime someone with bucks buys a new DD or rim drive TT, a used belt drive TT will probably go up for sale. With the supply of used BD TTs going up and the demand for BD TTs going down, there should be real bargains available in the used market for us mere mortals. Everyone benefits, except the manufacturers who can not keep up with the change in technolgy.

No price has been announced for the DC idler-wheel replacement motor. It will initially be sold in Japan.


You'd be astonished as to the performance that a KAB modded Technics 1200 can deliver for about $1K.

Everybody that has auditioned my unit has been impressed, including Steve Rothermel, designer of the Ridge Street Audio Sason loudspeaker. Call Kevin and he'll hook you up:

I've owned Linn, Transcriptors, Thorens, VPI, Pink Triangle, Mission, Systemdeck, Kenwood, Sony and maybe even some other belt drive turntables since the early 1970s. I was socialized in my early hifi days to prefer belt drive turntables. But some things don't stick. Continuously since 1980, I've had a Luxman PD441 (and later added a PD444) direct drive turntable. Various Linns, VPIs, Pink Triangles and Thori co-existed with the Luxman and it's the Luxman 441/444 that's always been left standing. They've won on sound, speed consistency, drive, tone, isolation, lack of noise, immunity from ambient factors. Rumble? I've never had so little on any turntable. It's essentially undetectable. If there's any coming from the turntable, it is dwarfed by rumble recorded into most discs. This Luxman series has a magnetic-repulsion arrangement for a "load-free" (I think it's really "reduced load") spindle/bearing.

A Verdier is interesting to me, but I stopped bothering with belt drive. I continue to get superb tone and energetic presentation from my Luxman PD 4XX turntables. Watch out for either a 441/444 and snag it.