I still stand by any isolation system that isolates the motors and the turntable in 2 separate domains (2 separate isolation devices) will in fact induce wow & flutter as the turntable & motor will vibrate independent of each other. This in itself must be considered. So, then we can postulate the best isolation will be a wall mounted stand with the motor suspended apart from the turntable. Unfortunately not a possibility for me and for most.
So back to basics, it is important in the design of any turntable that the motor has as little vibration as possible. This can be measured but in fact no currently published magazines in the US ever do such a measurement. Neither do they measure speed accuracy. But if I remember correctly there are some magazines in Europe which do such measurements. I wonder what motors measured best in terms of speed stability (at the platter, not motor) and in terms of vibration at the motor directly and finally how much vibration is transmitted to the platter/LP from the motor. All good questions. So now, I will also suggest a good isolation system or stand will in fact absorb vibration from the motor and also keep it away from the all important stylus/LP interface.
Now, on to the theory behind more motors. I have thought extensively about this. I am by no means an expert but put forward the following points.
Syncronizing multiple motors does have its challenges and might lead to the less is more philosophy from this perspective.
While a motor pulls the belt on one side of the pully, it in fact pushes the belt & creates slack on the other side of the pully
Using 3 motors will have a "take up motor" that will pull the belt and reduce the slack amount of belt being pushed.
Also 3 motors allows for less contact area between the platter and belt. This results in less surface resistance and less induced vibration from the motor through the belt to the platter. But also, this results in less realized torque at the platter, as there is less contact between the belt and platter. Again 2 items in conflict with each other. Ultimately you will need to let your ears be the judge. I know I have, and have spoken privately about my conclusions with my audio friends.
Back to isolation, I am in agreement that more weight on top of a stand will give you a lower resonant frequency but I think there must be some way to come to an ideal number. I forget my physics as it is over 20 years ago but for anything to isolate it must vibrate. If it is too stiff it won't work. Just think of the difference between a Cadillac suspension compared to a sports car or BMW/Audi for the Germans. One is softer on your but while the other wobbles more. Ultimately I find the stiff suspension of a car better, but ask my father and he would say to opposite.
I am using springs for my stand as many have seen. I wonder if reducing the # of springs will improve isolation. I know reducing the mass on top of the stand sounded worse as the resonant frequency rose too high. But then I might as well use less springs. I wish I remembered my spring constants etc. |
That's an interesting thought Dgad. I wonder if Thomas thought of using one motor and 2 passive pulleys. Arthur K from Funk Firm uses such a scheme and calls it Vector Drive. |
Dgad, suspension in cars and isolation from periphery vibrating ground (shelves, floor, wall) has very little to do with each other.
While your thoughts do indeed reflect some popular high-end audio "theories", they are not on a solid physical basis and are not hitting the topic.
In resonance frequency and the isolation from parasite vibration "we" are - should..... - seek a resonance frequency below 1 Hz.
Check the website of Minus-K and other companies dealing and specializing in this to get some insight into this topic.
3 motors will introduce - as they can hardly be synchrozised - 3 sources of error into a rotating system.
To this just add the belts which do elastically speed up and slow down - i.e. introducing wow and flutter - the platter and you have a rotating system which is the very opposite of constant unaltered speed.
You don't hear that the TT sounds worse with multiple motors?
Most likely because the bearing is now force free if the motors are situated in a manner that the bearing is horizontal free of force or close to that.
As this will "better" the sound, most will credit this improvement to the multiple motor situation.
However - using only 1 motor and 2 counter-bearings in the positions of the other "motors" instead will further improve the sonic presentation.
Multiple motors is the very same conceptional error as with multi-tubes or multi-transistors output-stages. As the individual tube/transistor/motor is always NOT identical in all parameters to its "comrades" the resulting "signal" is itself not homogenous but "wobbling".
This is something to think about before telling me how wrong I am.
It has to do with strict logic and theoretical model without prejudice.
We should have some members here who do enjoy exactly these ........... |
Ducati Rider,
Black Night get close and the fact that the motors are next to each other & contacting the belt almost at one point should be the best of all worlds. Syncronization would never be a problem in such a design.
Dertonarm,
I never said what I like better in these forums between multiple motors or not. Only in private, as my conclusions are not 100% verified. Further 3 motors in theory, can compensate for error as well. They would average the error of any one motor. Again, I am back to the argument there are no absolutes/
As for electron Microscopes and tonearms etc. I think we have to take into account 2 types of vibration. One would be "micro vibrations" and one would be Macro. There can be no one solution that is perfect for all scenarios. Imagine a sprung wood floor. A different isolation option would be needed for isolating footfalls as compared to airborne noise. |
Dgad, any isolation platform deals with mechanical vibrations only - airborne pressure (loudspeaker etc.) do of course need different measures.
A isolation platform with a resonance frequency below 1 Hz however does deal with microvibrations as well as footfalls. |
Dertonarm,
We are dealing w. both static & dynamic forms of isolation. I think both needs to be approached independently. But then there are active isolation systems that might handle all. In the end, for my system, I find that a low resonant frequency is a sonic ideal and as stated before one of the biggest sonic upgrades for the $ I have ever done. The other being my room (speaker position etc.). I have also stated here on the forum that even with isolation I found stillpoints to be a benefit. That also says something. But what I don't know (and I do wonder). It was immediately audible. I would imagine Stillpoints provide isolation in a horizontal plain vs a vertical one. Then again Stillpoints under my CDP in combination with springs is also a major upgrade and not expensive. |
Dgad,
if you are not using any vibration platform you may also go for better motors like Faulhaber or Maxon motors. If you supply the Faulhaber motors by Sorbothane you might really hear a difference to the motors now running.
This is not theory but approved by a Raven owner. |
Dgad, sorry again - Stillpoints, Spikes and other direct (or via one or several hard components...) coupling devices have nothing to do with isolation from periphery vibration. You just have a different "coupling" to the underground, but the vibration of the underground nevertheless does enter your components and its cabinet.
Static vibration vs. dynamic vibration ? You mean ONE frequency of vibration with constant amplitude versus a multiple of frequencies with alternating amplitudes ?
An isolation from vibration worth the name has to take care of all of this.
Thats why high priced isolation platforms (bench-tops and complex frames alike) are either active pressure supplied (Vibraplane et al) or very complex (Minus-K).
Some Stillpoints under your CDP will of course make a difference due to the relatively low weight and not very rigid cabinet.
The Stillpoint due dampen the groundplate of the cabinet and do - due to their extreme hardness - kind of speed-up the component-born vibrations to leave the cabinet.
But it does in no way isolate from outside vibrations.
Putting your CDP between two fairly heavy blocks of slate will most likely improve the sound even more, since now the cabinet can't resonate that easy any more and if, then with much lower amplitude and much lower frequency due to the vastly increased weight and direct large surface dampening of it top and ground plate.
If possible - give it a try.
I yet have to see the CDP which does NOT benefit from that particular method of large surface dampening. |
Back to the original question...You would be improving little and only in certain areas while sacrificing in others...You have one of the top tier tt's now...Save your money for other things, or at least other areas of your system.
Regards... |
...... or give a listen to a TT with a different concept. In other words - do audition a TT with comparable platter size and mass, but with a working low frequency suspension. The difference in low level resolution, bass speed, authority and "air" and the sudden lack of "grain" may give a completely new perspective on the performance and requirements of TTs.
Have fun on the journey! |
Dert
you give a very vague answer when you state ..."or give a listen to a TT with a different concept. In other words - do audition a TT with comparable platter size and mass, but with a working low frequency suspension. The difference in low level resolution, bass speed, authority and "air" and the sudden lack of "grain" may give a completely new perspective on the performance and requirements of TTs.
name names, what manufacturer employs these concepts? which might I add are at or near the price point of the TW Raven?
guys enjoy the music tolerate the equipment
braab |
Braa........ make your selection, choose the names you like - look around on A'gon and the magazines. Giving names here would just mean taking position and raising new potential for dispute.
But - to give just one idea.... - J.C.Verdier does offer 2 TT's in the price range of the TW Raven AC1 and AC3.
You'll find more.....
Have fun,
D. |
Hi DT...,
am I correct in assuming the 'Platine Verdier' does NOT use a motor controller, and therefore relying on belt slip/creep, platter mass, and controlled bearing friction to 'cancel' the effects of cogging?
Axel |
Hi Axel,
before we go back to 1.class school:
Do you know what a motor has to do?
To fight a battle? |
Trying to "controll" a heavy platter in motion with 33 1/3 rpm by a "motor" is a nice try. You have a constant "war" between the inertia of the platter and the torque and regulation of the motor.
I am sure we will have several protagonists for this principle here on Audiogon and in the "audiophile" community.
But we will find no protagonists for this principle among technical engineers.
Why ?
Well - obvious reasons, once it is given a serious and undogmatic view.
Direct coupling with quartz or whatever controlled high torque and precise motor giving the "pace" will always work quite well with low mass (= low inertia) platter.
Never against inertia.
We would then look at constant "war" with lots of tiny speed changes and everything but really constant revolution. |
Well,
1. Klasse or not. If I read the response it'd tell me that "Platine Verdier" can not work as a top tt should work, because it is at constant "war" with the -constant- bearing friction... hm,?!?
Hey, I guess I'm not ready for this engineering-101 type of analysis yet. Something tells me this is more opinion then knowledge based analysis :-)
One fact to be considered: motors (most? all?) in order to perform correctly/steadily - AC to make sure, since DC is all over the place due to other issues, need to operate AGAINST some sort of load, the more constant the better.
This would completely contradict this almost 'free-wheeling' notion that I seem to hear by Syntax.
Thomas, were did you obtain your engineering degree? In the 2. Klasse then?
Greetings,
Axel |
Well, it can be a endless discussion when you don't know what you hear. Most today "like" something or they read an "article/review" in a magazine, save 3-4 sentences from it and after a while they are transformed into "experience/knowledge".
Sometimes I wonder (no, wrong, I stopped that) how many Audiophiles think, what a Designer does is perfect. Ultimate. Lots are able to make enough money to buy expensive things (but only with a good discount of course/review "winner"), but on the other side they have absolutely no idea what these units are doing. And they are not seriously interested in that.
And even in the next life these discussions will go on...
One way to avoid it, is to try to visit audiophiles and listen to their Systems, sooner or later you will hear differences...the only decision you have to make then is:
- Do I "like" it or not...
- Is it right or wrong....
"In the kingdom of the blind, the one-eyed man is king"
You know, these 3 sentences... |
I know that this will lead to nothing but more questions, but nevertheless:
- operating the Verdier TT with a thread/string and minimal grip will minimize the requirements to the motor and maximize the benefit of the platters inertia to give excellent constant speed.
The one "key" to great results (very constant speed with literally no alternations) in high mass platters is "belt" (read: thread/string) drive with minimal grip/tension. The inertia does the job - and it does it better or the equal of the very best direct coupling/controller.
But it does so with the minimum vibration and literally no alternation in speed (due to motor/controller regulations, belt grip in conjunction with speed up and slow down due to belt inert velocity etc.).
There are 2 way to get good constant speed:
- low mass platter with low inertia driven by high quality and high torque motor/w controller (many examples - direct drive and idler drive and hybrid concepts by Denon, Sony, Luxman, EMT etc in the 1970ies/1980ies and later).
- high mass platter with high inertia and very low grip thread drive.
If you want to go with a low platter weight - fine.
But that will get you nowhere close to what is possible, due to the inner resonance of the low mass platter introduced by the tracking process itself.
You can try to dampen that with mats etc. - thats why so many TT's do benefit from tuning mats to a high degree.
Still - you won't get really dynamic low register, no "air" in the bass line, no real speed and a rather muddy and "warm" upper bass.
But many do like that. |
D.T.
y.s.:
>> If you want to go with a low platter weight - fine. <<
Not necessarily, in fact I have this suspicion from what I heard this far, there is once again some trade-of going on here.
I have heard the 'musical' mass-platters close to what you mention (alas not with loosish string), - and very 'fast' lower-mass-platters ~ 4.5kg, that can sound a bit 'restless' even nervous like.
So Thomas, where he sees it, seems a bit unclear to me, but since he likes to 'stir the pot' he may like AND dislike both, in the fashion of a true chilled out cynic?
In the case of a ~ mass-platter (of sorts), Transrotor Z3 with a jolly tense neoprene belt, it goes as much the route pretty of a Thorens 2010 arrangement.
Then we have the 'Platine Verdier' with yet heavier platter and a rather LONG, no-stretch Kevlar? string. (Tensioning and length is up to the user - like how long is your rack space?)
If I'd have to pick between the 3, I guess I'd be still looking at the 'Verdier' rather.
Then we have the SME system, fast, dynamic --- BUT not necessarily all what you'd call a: really dynamic low register, [or] "air" in the bass line, YMMV.
Now, so we wont loose the thread subject -- where do our 2 contenders, TW & Da Vinci, fall into the scheme of things?
Note: I once tried a no-stretch string in place of a square (stretchy belt) on a RPM 9 ----> result: Plain awful...
Greetings, |
Axel, ...... back to the object of this thread: in terms of both - craftsmanship and tooling - I would go for the Raven (but I don't need to....).
Both - Raven (whatever incarnation) as well as Gabriel do both desperately need a working isolation to be able to show their merits.
Putting them "hard-coded" on any solid ground/shelf, rack means simply giving (rather throwing....) away 50% of the possible performance.
As for the RPM 9 with thread.
It needs some experience to get the right "feel" (if you don't have the right equipment) as far as the thread tension goes. Too much - pretty bad. Too less - pretty bad too...
"Right" tension - pretty amazing......
And yes - I would take the Verdier any time above the two contenders.
Preferably a Verdier made prior to 1993. |
Dertonarm,
Did you ever test the Verdier for stray magnetic fields above the platter that would in fact negatively impact a cartridges performance by interfering with the cartridges magnetics? |
Dgad,
yes - I did. About 18 years ago. First I was suspicious about this too. The big magnetic rings relatively close to the tiny magnets inside the cartridge,....hmmm.
However, - as the tests showed (and some measurements done at the technical high school Munich) the 2 magnetic rings are embedded inside two steel "rings" which do very effectively shield the magnetic field - at least from dispensing vertically towards the platter surface.
There was no detectable interaction with the magnets in cartridges nor did the test show any induced hum.
It performed flawless with a very wide range of cartridges from Ortofon MC-5000, Supex, Koetsu, FR, Grasshopper v.d.Hul, Dynavector,Kiseki, Ikeda EMPL, SPU and Miyabi.
The Verdier is a fairly "raw" concept and was from its very beginnings as a DIY-project introduced in the late 1970ies in the french L'Audiophile-magazine. It is however a smart design which gives - proper set-up - extremely good sonic results and has some very clever design features which all do work for the better in performance (if not in looks....).
The versions built prior to 1993 are sonically better to later production.
The versions with pure magnetic bearing in the horizontal plane - no added ball.
I am referring to the La Platine Verdier only. |
A permanent magnet cannot induce hum. There is no need to test it. |
The stray magnetic field if unshielded could change VTF as the cartridge moves across the record closer to the spindle/ magnetic bearing. just try working on a cartridge with any screw driver. |
I just saw a report from Jonathin Valin from TAS returning from DaVinci in Bern
http://www.avguide.com/blog/trip-switzerland-and-da-vinci-audio-labs |
