Is magnetic drive an ultimate concession to the superiority of direct drive?

woodsyi · « **on:** 19 Oct 2010, 05:29 pm »

Looking at the Kodo Audio Beat table with mag drive at RMAF, I am wondering if this is the new thing that will put direct drives over the belt drives. I also noticed that Peter (Soundsmith) Lederman is now using Teres Certus in his room showing his Strain Guage system. Belt is always going to lose something in the transfer of energy. Nor can belt drives be quick and adroit at speed control when massive platters are used. High mass is great for stability but slow to change also means it can't correct itself quickly if the motor is not constant. On the plus side, belt separates any motor vibration from the platter which is the big knock on DDs. What if you can get the DD control without the motor vibration?

I understand the Beat is really a Garrard 301 modified by Steve Dobbins. I think he does mods on SP10s too. Other magnetic drive TTs I can think of are Clearaudio Statement and Teres Certus. I assume that these physically separate the stator on the plinth and the rotor on the platter. Is this the wave of the future?

TheChairGuy · « **Reply #1 on:** 19 Oct 2010, 05:46 pm »

Quote from: woodsyi on 19 Oct 2010, 05:29 pm

Is this the wave of the future?

More like good idea revisited.

I have the JVC QL-Y66F, circa 1985, and it features a has a high-tech magnetic bearing to reduce friction by elevating the spindle. It also has magnets in the tonearm for some of the same reasons...and adjustable damping in horizontal and vertical planes

It's about as good as my VPI Classic...which has no magnetic properties (other than the sonics

)

I think so many of us have been diddling around with mostly sideways turntable 'upgrades' too long...it's like splitting over hairs. The Soundsmith Strain Gauge was the most significant step forward in vinyl reproduction that I have ever heard, frankly.

Get a good table, a nice arm mated mass-wise to a Strain Gauge...and bite the bullet for the $5500 for cartridge/preamp. That's where I'm heading.

Absolutely, $6500 spent on a table, arm, and Strain Gauge (say, a Rega P3 + Strain Gauge) will best same $6500 on a better table, arm and a MC/MI/MM cartridge.

John

woodsyi · « **Reply #2 on:** 19 Oct 2010, 05:58 pm »

I am not quite that sold on Strain Gauge but I think I am leaning toward Certus or something. I think I will be calling Chris B....

Plus, I want the 2 arm plinth.

TheChairGuy · « **Reply #3 on:** 19 Oct 2010, 07:11 pm »

You KNOW I'm sold on the SoundSmith Strain Gauge

Just as soon as I see us over the hump of a 5% price increase our factory just gave us (and they're worried about deflation??

) I intend to buy a Strain Gauge.

I'll get over the $5500 entry fee somehow.

That might well be a few months, but that day is coming

Go for the 10 to 12" arm option....I find it hard to go back to a 9" arm now having enough piano rendered so much better with the better tracking longer arms.

John

woodsyi · « **Reply #4 on:** 19 Oct 2010, 07:38 pm »

I want 2 arms so I can dedicate one arm to mono. The Miyajima premium mono pickup was quiet impressive. I have heard different arguments on how to cancel "vertical" noise on stereo pick up playing mono LPs, but it could be that you really need a mono pickup. This one sounded really good.

vinyl_guy · « **Reply #5 on:** 19 Oct 2010, 07:43 pm »

Quote from: TheChairGuy on 19 Oct 2010, 05:46 pm

The Soundsmith Strain Gauge was the most significant step forward in vinyl reproduction that I have ever heard, frankly.

Get a good table, a nice arm mated mass-wise to a Strain Gauge...and bite the bullet for the $5500 for cartridge/preamp. That's where I'm heading.

John

Me too. The sound coming from the Strain Guage was the best I have ever heard from any cartridge. It was heavenly

woodsyi · « **Reply #6 on:** 19 Oct 2010, 08:08 pm »

How much of the heaven came from Certus? That's the TT and Teres arm that Strain Guage was mounted on.

vinyl_guy · « **Reply #7 on:** 19 Oct 2010, 08:37 pm »

Quote from: woodsyi on 19 Oct 2010, 08:08 pm

How much of the heaven came from Certus? That's the TT and Teres arm that Strain Guage was mounted on.

I heard the Strain Guage on both the Certus and the VPI playing vinyl I brought (R & R of course

). No question the Certus was the better TT & arm, but I really liked what I heard on both TT. So I attribute enough of the "heaven" to the SG to still want one.

neobop · « **Reply #8 on:** 19 Oct 2010, 08:41 pm »

I was looking at an ad for an old Luxman TT. It had magnetic bearings. I think it was the 555. IMO DD has always been better than belt. The belt drive gestalt was perpetrated by manufacturers who didn't have the capability or imagination to make a DD. 20 yrs ago the Goldmund DDs beat ALL the belt drivers. Which is not to say that there aren't some excellent belts today, or 20 yrs ago for that matter.

I've read other raves about the strain gauge. These claims must have something to them. Looks like $5500 is for entry level. It goes up to $15,000.
http://www.sound-smith.com/cartridges/sg.html

I buy cars for less than that. LOL
neo

Toni Rambold · « **Reply #9 on:** 19 Oct 2010, 10:48 pm »

The Teres Certus is a direct drive tt with a special synchronous motor with a permanent magnet, so a motor control unit is unnecessary.
The Garrat 301 is an idler wheel tt.
Both tts have a coupling between motor and platter - direct or in case of the Garrat a rubber wheel - and the belt is the coupling element of a belt drive.

The Clearaudio Statement is a free magnetic field drive tt with a lower and upper disc with neodym magnets and an air gap of several millimeters between the two discs - so there is no mechanical coupling between motor and platter.

Here is an example of the least expensive free magnetic field drive tt:

right side below: drive unit with lower disc and 10 neodym magnets.
left side holding: upper disc.

The Strain Gauge Cartridge is a very old hat,
which uses the Piezo-Electric-Effect.
30 years ago, John Iverson, then of Electro Research
built a beautiful "preamp" (constant current source)
and used a Panasonic 451-C Strain Gauge Cartridge.

See TAS 20, page 441f

see also: http://www.avguide.com/review/soundsmith-strain-gauge-cartridge-and-phono-preamp-tas-201

lazydays · « **Reply #10 on:** 23 Oct 2010, 05:23 pm »

looks like a plastic Final Tool! <g>

I would tend to avoid massive magnetic drives till someone can prove they don't cause problems elsewhere (it dosn't take much to cause a cartridge to act stupid; let alone the cables). I've check my string drives in the past with some very fancey equipment (electronic strobes and vibration analysis equipment) and never say a problem. But on the otherhand the magnetic poles should cause a pulsing in the rotation (nature of the beast), but how much remains to be seen. In the mean time I still plan on croaking with the same two tables in my possesion as all that plastic still has not shown me anything better
gary

lazydays · « **Reply #11 on:** 23 Oct 2010, 05:25 pm »

almost forgot!
a direct drive is never ever gonna run with the big dogs
gary

neobop · « **Reply #12 on:** 28 Oct 2010, 11:21 pm »

Quote from: lazydays on 23 Oct 2010, 05:25 pm

almost forgot!
a direct drive is never ever gonna run with the big dogs
gary

BS.

Delta Wave · « **Reply #13 on:** 28 Oct 2010, 11:51 pm »

Quote from: neobop on 28 Oct 2010, 11:21 pm

BS.

Indeed!

Berndt · « **Reply #14 on:** 29 Oct 2010, 03:42 pm »

We use mag drives for chemical pumps.
I keep eyeballing old pumps for donor parts to build a DIY mag drive.

Rim, if I can be of service, I'd be happy to help with a custom plinth.

vinylphilemag · « **Reply #15 on:** 29 Oct 2010, 04:05 pm »

I'm not convinced that either drive technology is inherently superior, because there are examples of excellent TTs that use both. For examples in the direct drive camp we have the Rockport System III Sirius and the Clearaudio Statement, and in the belt drive camp we have the Walker Proscenium Black Diamond II, the Bergmann Sleipner Reference, and the SME Model 30/2. So I don't think it's so much the drive technology per se that's important, but the implementation thereof.

Toni Rambold · « **Reply #16 on:** 29 Oct 2010, 06:46 pm »

Quote from: vinylphilemag

For examples in the direct drive camp we have the Rockport System III Sirius and the Clearaudio Statement

...

... as I have posted before the Clearaudio Statement is not a direct drive tt.

It is a free magnetic field drive tt:

... the lower platter (with neodym magnets) is driven by a DC motor by a string.

Regards Toni

vinylphilemag · « **Reply #17 on:** 29 Oct 2010, 07:52 pm »

Quote from: Toni Rambold on 29 Oct 2010, 06:46 pm

...

... as I have posted before the Clearaudio Statement is not a direct drive tt.

It is a free magnetic field drive tt:

Regards Toni

I sit corrected, but my original observation stands! It also seems that we should actually be differentiating between THREE drive types: belt, direct (i.e., linear motor with no physical contact between the motor and the platter), and rim (although I suspect that many would consider rim drive to be a subset of direct drive, which I suppose it is).

cbrady · « **Reply #18 on:** 30 Oct 2010, 12:05 am »

A few corrections. The beat is not a modified Garrard, it is direct drive.
The Certus turntable is not magnetic drive, it is direct drive.

Direct drive and magnetic drive have nothing in common. Magnetic drive provides a compliant coupling between the driving wheel and the platter. The behavior of this coupling is essentially the same as a belt. This filters out out cogging from the motor. The net effect for either a belt or magnetic coupling is a low pass filter between the motor and the platter.

Magnetic drive takes a turntable in the opposite direction from direct drive. Any sort of compliance between the motor and platter delays delivery of toque to the platter. This is responsible for the lack of pace and drive that plagues belt drive turntables. Direct drive turntables on the other hand often suffer from cogging effects that are filtered by the belt (or magnetic coupling). To get top level results from direct drive puts extreme demands on the quality of the motor, making direct drive expensive and difficult. But it also hold promise for the most uncompromising performance.

WGH · « **Reply #19 on:** 30 Oct 2010, 02:09 am »

Here is some info about 'The Beat' from RMAF: