Audiophiles "opinions":
"I wrote it the right way, so it was copied the wrong
way right. I mean the right way wrong." :-) |
Dertonearm, The billiard experiment you cite is an interesting analogy. It seems to me that when the billiard ball encounters the billiard table, it is first of all sitting on the felt cover. The outcome of the experiment would seem to depend on how much of the kinetic energy of the ball is absorbed by the felt/stone entity vs how much is reflected back into the ball. That has a lot to do with what happens right at the interface of the ball and the felt/stone. Different kinds of felt might affect the outcome, for example. Billiard table stone is usually slate. Slate from different locales around the world has very different hardness. Hardness or density would affect what portion of the energy is absorbed vs reflected. In other words, it's not only about mass. High turntable platter mass would be good though to sink the absorbed stylus energy as heat rather than to reflect it back into the cartridge, if the platter material were of a nature to absorb enerby from vinyl rather than to reflect it. So platter composition would have something to do with this phenomenon as well.
There is also the question of whether ideally one wants to absorb the energy imparted by the cartridge or to reflect it back to the cartridge. In this aspect, the billiard ball analogy may fail. I cannot argue with your listening experiments, as you cite them to Mosin, but I am guessing you were using a belt-driven tt at the time. So there is another question of whether the drive system makes a difference. I have no basis to form my opinion on that except to say that I hear more solid base lines from upper mid-level direct-drive tables than from similar quality belt-drive tables, when the latter have platters of much higher mass. |
Lewm, on the "billiard analogy" ALL other factors (level, felt/fabric, size etc.) are the very same - the only difference being the mass underneath the felt. Be it slate, granite or (seldom...) other hard stone. Check out billiard tables - the huge difference in prices of different models by the same manufacturer is direct related to mass (mass underneath the felt...) and usually the published thickness of the stone platter underneath the felt is the "price factor" per se.
So - lets just predict that it is the larger mass only which makes the difference (and this too is the technical fact..).
The larger the difference in mass between two singular bodies - one (the smaller) moving on the other - the less energy is absorbed/withdrawn from the smaller moving mass by the larger mass underneath. Resulting in more inherent energy "staying" with the moving corpus and is used for movement = longer distance running.
In billiard - which I was into in my youth - this is common sense and knowledge. At least in Snooker and Karambolage - not sure about Pool....
So - let just take that fact for granted.
Of course the inner damping of the platter does add to the overall result, as does the clever sequence of different speed of sonic distribution in different materials, but the total mass has a paramount impact.
Take the platter of the vintage Basis Debut Gold.
Its not that heavy (but still above 20 lbs I think) and it is very well damped despite its vacuum suction.
However, its lower bass performance - while being very good - can NOT compete with the low register performance of platters twice its weight.
I too wished it would be otherwise.
My new turntable thus features a very complex platter with a total weight of 135 lbs (static net weight ...... but there will be 2 inertia units going with it.... so the dynamic mass will be , well - immense).
Not because I like heavy cylinders, but because I know what I need to do to achieve what I want.
The drive system does make a difference, but to a much lesser extend that widely assumed.
It does make a sometimes huge difference with poor (cheap) motors and/or light platters.
I already had a great argument with the idler-drive and direct drive fraction here on Audiogon some months back.
I know why I use the drive I am using and I am getting the results I wanted and which others won't believe.
For the model set up in my earlier post there is only one thing that matters - brute mass.
The other points mentioned do matter too - and a few more.
Enjoy the journey,
D. |
Dertonearm, I am thoroughly enjoying this discussion, and I do thank you for your patience with my recalcitrance. I feel like this is a Socratic search for truth, not an argument. So.... you wrote, "The larger the difference in mass between two singular bodies - one (the smaller) moving on the other - the less energy is absorbed/withdrawn from the smaller moving mass by the larger mass underneath." I think this statement is incorrect for a ball rolling on a flat inert surface, provided it is a given that the surface does not deform due to the pure weight of the ball. (We could agree that a ball won't roll very far in mud.)
I know your conclusion re what type of tt is best is based on extensive listening and even more extensive trial and error experiments that I cannot come near to replicating. So I would not dare say you are wrong in that regard. I am just commenting on the why of it. |
Dear Lewm, this is all a matter of the conservation of energy. The rolling billiard ball is just an analogy to illustrate (roughly..) the behavior of two masses in contact with each other and with VERY different individual masses and the smaller mass (stylus) in movement on the surface of the larger mass. What I am trying to do is to illustrate that point and I must apologize, as I am apparently not very successful.
Sorry about that.
In any case maybe soon some seasoned members will join us here and tell me how wrong I am and that I have no clue of a) physics and b) turntables.
So best to do for us all may be to just forget my model and that funny idea with the billiard table and that nonsense about conservation of energy and carry on as before.
Enjoy the journey,
D. |
As I understood you are finished with billiard playing, so let´s spend one more thought on audiophile opinions.
A good definition is: The difference between fact and opinion is that a fact is something that is empirically true and can be supported by evidence while an opinion is a belief that may or may not be backed up with some type of evidence. An opinion is normally a subjective statement that can be the result of an individual interpretation of a fact.
I hope we agree that we discuss more or less on the bases of opinions and not all the time on facts?
Assessing the quality of TTs we may judge on some performance data, the kind of technology which is used, the acceptance of the audiophile forum (we all), the activities of the sales forces behind the product, maybe pricing as well (?) etc. In the end we select favorites which mirror the momentary level of our systems. In this stage our opinion about the brand and the type of TT is formed.
To assess audiophile opinions we have to have a close look at the experience of the opinion makers, maybe at their systems and at the quality of their recommendations. This is the kind of erratic approach we are following usually in this wonderful journey. But in some way it is following an interative path of experiences - with positive results.
When it comes to listening I do think that maybe 99,5% among us feel like an audiophile expert being able assessing TTs. Of course we hear the difference of TTs, tonearms and cartridges. We go to fairs, we visit friends with good systems, sometimes we are invited by manufactures to assess prototypes etc. In the end we usually end up defending our grounds more or less stating so called facts (which are sometimes opinions). That´s the difficult side of opinions. |
Thuchan, you are so right. In the end all of us, except for Dertonearm who was in the business of turntable R&D, have opinions based on very narrow experience. That's possibly why it is of interest to consider the physical principles involved in the playing of an LP. Maybe science would take us closer to the highest form of the art. Anyway, it's fun.
DT, Yes, the energy must be conserved according to Newtonian Mechanics, but I believe it is dissipated as or converted to heat, as the cue ball rolls across the felt surface. The two masses (ball and table) are passive actors in this process; the bigger mass of the heavier slate would if anything more readily dissipate the energy in the ball than would a smaller mass of slate, or so it seems to me. I don't mean to preach; this is just me thinking out loud. I am waiting for my physics professor to correct me. |
Lewm, well - pretty fruitless to discuss a long proven physical fact (which the longer running distance on the thicker slate plate billiard table is) or at least it direct (objective !) technical result - isn't it?
Well Thuchan - in fact we are not finished with billiard playing ( and to me it sounds more and more that we never will...) - but I am leaving the table now for good.
Cheers,
D. |
Lewm, Dertonarm: You may continue billiard playing. I did`nt want stopping you. Maybe next year when we are facing new tables... |
Getting back to the original question posed, why don't you try the new Basis Inspiration TT? It's their finest TT and it looks like a spectacular TT. Basis products have a great reputation for wonderful music reproduction.
On the other hand, have you tried more arm and cartridge combinations? You could even do this with adding a Graham Phantom MKII to the TW-Acustic with a couple of arm wands. Any high end analog dealer in your area should let you try out some of their demo cartridges over week ends. I know that Bryan at Analog Room San Jose, CA lets his high end customers do home demos. Maybe that's a way to get the sound you want without spending another $50K. After-all, you do have one of the very best TT's in the world.
If not that, then go the Walker route.
Good Luck! |
Having ben a high end dealer and set up many turntables - Linn, Pink triangle, Roksan, Sota, Oracle, SP10's, Mapleknoll ( Walker ) etc yrs ago my conclusions are as follows ; go back to first principles - the stylus, arm, platter AND motor drive MUST be absolutely rigid and referenced to each other to obtain ultimate pitch stability. I have found that most suspended tables suffer considerable wow. Similarly if you consider the first princiles I espoused - air bearings are out, not rigid, that rules out the Walker, Da Vinci & Air bearing micro seiki's. You need to consider the bearings - the Raven has a teflon thrustpad as do many high end decks, thats like playing your record on a spongy pudding - the platter and cartridge coupling are not rigid. I currently run a Final Audio Parthenon - high mass, copper platter, all chassis components made of composite gunmetal, totally rigid and massive ac motor with a power supply that includes power regenerator for accurate voltage and hz etc. This designed in the 70's ( Absolute Sound ultimately wrote it off as they mounted it on an air bed - completely against the designers philosophy ). It is mounted on a custom stand with true mechanical grounding ala Goldmund. The only turntable I lust after is the Verdier - with ball installed in the bearing so it is grounded - but dial the air pressure so that the grounded bearing only sees 4-5 lb ala the Continuum. Tonearm recommendations - no air bearings again not rigid - I use Naim Aro as the unipivot has true single point grounding and is rigid given correct arm/cartridge matching. Cartridge recommendation - currently use an Ikeda - no cantilever slewing around creating time distortion, diamond mounted n a hoop - so speed of a Decca without the hassles. Direct drives - have 2 friends with SP10 MkIII's in custom plinths - I'm not convinced - the sound is chopped up ala digital - have reservations about direct drives with constant speed correction impacting stability. Non air bearing Micro Seiki's and Melco's are also on my list of resonable decks. |
Hi, I am not enough of a technical guy to understand all the comments and recommendations about designs, etc. I just trust my ears. Anyway today I had the good fortune of listening to a well set up Walker Black Diamond (+ Goldfinger v2 cart) and was impressed. Extremely detailed and transparent with superb soundstaging and imaging. It was very flat and neutral that i couldn't hear any part of the frequency spectrum that was more prominent than others...i suspect as a result that it was very non fatiguing to listen to, which i did for 2 hours. Best TT i heard so far. |
Dear Dover, air-bearings are not out. Just look at the new Bergmann concept. It looks that more and more developers dealing with Top-High-End TTs are having an eye on air bearings. For what reason? |
Dear Dertonearm, Sorry to see you go. We could discuss it privately. I allowed all along that my reasoning could be faulty, but I have yet to hear the science-based counter-argument from you for your thesis that higher mass of the slate would result in a longer run of the billiard ball (which of course leads to the more relevant argument that higher mass platter per se gives better sonics). To say that your proposition is a well known given fact for billiard tables is not convincing to me in the slightest. It seems too obvious to say it but it was once a well known given fact that blood-letting is the best treatment for infections.
Dover, if you did not have your concept of how the servo mechanism works in a direct-drive turntable, would you still say the sound of an SP10 Mk3 is "chopped up"? What do you think is the frequency of servo action once the 22-lb platter of the Mk3 is up to stable speed? I would guess it is not sufficiently frequent to give the phychoacoustic effect of "digititis". I think your impression may be biased by your preconceptions. It happens to all of us. I am running an SP10 Mk2 right next to a Lenco w/idler drive. Comparing the sounds of the two, I hear nothing like what you describe. Since the Mk3 platter is 3 times heavier than that of the Mk2, I expect the Mk3 would be even less likely to exhibit the artifact you describe. |
The Black Night does not use a teflon trust plate, but considering the 1-2 gm force of stylus I don't get the sponginess of an teflon trust pad once compressed. I wouldn't understand it w. an air bearing as well. The only issue w. an air bearing would be the variations in pressure etc which I have no experience with.
Black Night compared to Raven AC? It is more open on top and yet has much the same character in sound. Difficult to explain, you need to hear it. It is earily silent. But shortcomings that were missing on the AC in the vinyl chain are apparent w. the BN.
The easiest way to compare the 2 is to say where the best SACD releases was close to Vinyl w. the AC, on the BN I need to start from scratch. Kind of upsetting as I wish digital w. all its convenience has a prayer. SACD is close, very - but then go listen to the AC. You will be shocked. Then listen to the BN and the shock leads to disappointment in digital. But... Real to Real is still the best I have heard. And that is an even bigger step up. Just not for me. |
Transrotor Apollon, maxed out with 80MM platter, Magnetic drive bearings, 3 motors, SME V, and outboard Transrotor drive controller with manually adjustable fine tuning for speed. I am just saying, for me, my turntable is the "LAST" part I will ever think about changing for my main system, forver. Non-Suspended on Clearaudio MontBlanc turntable stand. I have never had any issues that people talk about with many other turntables; no bass feedback even at 100db plus levels and a large 15" subwoofer, no vibration pick up from walking, absolutely quiet and very stable. Ultra black backgrounds and velvety smooth highs with that silence between instruments and delicate and intricate breathing and parting of lips that you can hear in a lot of music, but just can't because the system is not high resolution enough.
I am not making a sales pitch, but if your system is already offering you all of that, then you have reached virtually the end of the upgrade road, the expenses from here on out will be for exotic materials and who knows what else to give you that .05 increase in quality.
I too was on the hunt for an end of life upgrade path years ago, and that is exactly what I did. I only worry about changing tubes out now when I need to and never the turntable, except when it is time to retip the Benz. I have a spare MC for that very purpose.
Good luck.
Ciao,
Audioquest4life |
Audioquest,
I saw one of your Transrotors in HK. Very nice bling :-) |
Laws of physics say that for every action there is a reaction, therefore any "give" in a bearing means you are losing the leading edge ( I think you will find the downwood pressure/energy of the minute stylus tip is surprisingly high ). For an air bearing or magnetic bearing to be completely rigid they would have to have infinite pressure - impossible. The only benefit of air bearings is that they are much cheaper than a decent mechanical bearing that does not induce vibration and noise, they dont wear out and they are more forgiving of poor set up ( soft bearing = soft sound ). Remember Enid Lumley of TAS - drop the air pressure until it fouls and then raise it slightly - this gives you the softest mushiest sound possible.
Lewm
I can only draw on experience - listening to the L07D demonstrated the later Goldmund direct drives were cogging, similarly when comparing the SP10 Mkiii against the Mkii you can clearly here the instability of the Mkii. The mkiii is the best dd I've heard - I'm just not totally convinced. I would not be averse to picking up an SP10 mkiii for experimentation to find out more. |
Writing off air-bearing featuring TT's categorically because of an individual point of view how bearings in TT's work and interact with tonearm, plinth and underground is not at all an approach worth further consideration. While the SP-10 MK3 is a nice and well made DD-TT, it is nowhere near an estimated nor possible optimum in TT design. It is a 30+ year old design made for broadcast applications and following a certain, - then en vogue - principle of the day. As the idler-drive TT were 2 decades earlier.
An air bearing (working...) being less expensive than an average "true mechanical grounded" bearing ? What do you think the bearing in the SP10 MK3 did cost ? Whatever you guess now - its not half of that figure.
It is somehow funny, how - especially in TT design - everything is worshipped which tries to get around physics and real investemnt in material and financial resources. The one and only real clever approach in making a good cheap TT I have ever seen was Bill Firebaugh's initial design - it only suffered seriously from choosing the wrong velocity in its damping fluids.....
True mechanical grounding ? Tell that anyone in any laboratory working with microscopes - you're in for a good laugh and instant empirical proof that it won't work.
We will never see a lightweight TT nor an unsuspended one, with a platter less than 30-50 lbs coming anywhere near the point of closing the book on TT nor approaching its true frontiers.
As we all will see - as they will come and go in half years turn.
The same they have done so for the past 40+ years in high-end. |
I can certainly understand the microscope analogy. However, microscopes don't create vibrations nor do they interpret them, so to some extent the analogy is not complete as a comparison. I know many of the isolation techniques used in audio look at those used for elaborate electron microscopes. Turntables are selective vibration detectors, however, with the vibration starting at the device. They also have to decide how much vibration to "keep" and how much to "filter". That is somewhat different from maintaining a clear visual field in a microscope. |
Managing the vibration introduced by the tracking process is a different matter. This is not disputed in any way by me. However - the isolation from OUTSIDE vibration traveling into the TT - is essential, a true conditio sine qua non. The inherent vibrations have to be eliminated inside the system (here: TT) - the external vibrations have to be kept away from the system (again: TT...).
An ideal solution/scenery: different room to eliminate sound pressure effects PLUS isolation from building resonance by means of a vibration isolating platform tuned for below 2Hz resonance frequency - 0.5 Hz if possible.
Regarding the isolation from outside vibration TT's (at least the ones worth mentioning and claiming themselves to strive for the state of the art) do indeed have the very same needs as an electron microscope.
Avoiding having the very tiniest details smeared by low frequency outside vibration moving into the TT system.
Anyone not accustomed to this, I strongly recommend giving their beloved TT a listen after setting in on a Vibraplane or Minus-K with enough load close to the maximum allowance.
The following listening will answer all questions in a matter of 20 seconds.
I know it - I have watched the faces of various audiophiles often enough in those first seconds.
After that all critics turned to true believers in the simple laws of mechanic.
But - its kind of costly and won't work with some of the fancier "high-end" rack due to lack of guts (here: stability).
It doesn't look to good either.
A well loaded Vibraplane moves into the game very much like a solid full linebacker with 240 lbs+.
But after all - this is a game for real men.
And here once again the boys are separated from the men - as the later do what has to be done and not just talk.
Enjoy the journey,
D. |
Isolating the turntable system from external and airborne vibrations is certainly essential. That creates one point of vibration attenuation and frequency reassignment from external influences.
A lot of the above discussions seem to bear on the issue of the various interfaces of the vibration detection system, itself and how they "drain" into this interface between the turntable system and the outside "world".
For instance, a theoretically perfect rotating platter with a perfect gravitational field on a perfectly frictionless air or magnetic bearing creates another point of isolation within the turntable system itself. Also, the more frictionless the bearing, the cartridge modulations and imperfections of the vinyl will create centripetal and centrifugal de-stabilization effects over time which can only be reflected back into the vinyl/cartridge system from the platter to the cartridge. I imagine this is why the Caliburn system unloads the mass but preserves a mechanical interface, to stabilize this interface and create a point of vibration drainage apart from the cartridge interface, itself.
Also, a linear air bearing tone arm, also theoretically frictionless, creates another point of isolation from the internal interfaces of the turntable system. Although this may minimize tracing distortion, it creates two different effective masses and another isolated vibration interface. Unless the damping from this system is perfect, the cartridge sees reflected vibrations from the tone arm system itself without an external source of vibration drainage. Also, if the friction is theoretically zero in some dimensions, the cartridge is free to wag the tone arm without inhibition and is not restrained around the groove modulation. So this system is not restrained or drained as with a mechanical inerface.
If you have an air bearing platter AND an air bearing tonearm, you have two theoretically frictionless points of isolation mediated by the cartridge interface. This seems like you have one tail (the cartridge) wagging two dogs (platter and tonearm) against two points of isolation without drainage, relying on perfect damping from the two points of isolation. I don't really see how this is ideal even in theory.
Also, on SME website, they cite that material density and stiffness are at least as important as sheer mass. The SME tables create a "mass effect" by using stiff, high density horizontal plates and turntable platter rather than sheer mass. |
Dertonarm, Have you heard a turntable set up on an active anti-vibration platform like Halcyonics? These are very expensive, but they reach down to 0.5 Hz and should be more effective than a Vibraplane. I wonder if this alone would improve the Raven AC-3 substancially. |
This discussion is going in a direction that isolation (passive or active) is the solution for everything. I am sorry to say, it is not. It is a step up in Performance but an average Turntable placed on a isolation device is still an average turntable. It only sounds a little bit better than the same without it. A cow will be no horse. |
Syntax, it might me a fruitful approach to test the halcyonics duo or/and the halcyonics sandwich, also against the Vibraplane. As they say they produce custome made units at the moment you get a sandwich unit only in 800mm x 800mm which is somehow an oversize for most audiophiles.
As you might agree we both are not keeping cows in our barn or do we? |
Dear Thuchan, smart as it looks, expensive (and thus tempting...) as it is and originating from both our fatherland ( and thus I would love to promote it for its origin alone, - against all global thinking...) with its long time fame for excellent engineer approach - from my now 17 years 1st hand experience with active and passive air-supplied isolation for turntable design, I would always go for the passive option.
I know very well why and have learned from the past. The Halcyonics is active compensation by mechanical means.
Very similar to the feedback-loop in amplifier design and/or pre-compensation in loudspeakers (Backes&Mueller...).
The Minus-K ( almost as expensive, american made and pure passive in a VERY smart manner...) is more than just a serious contender.
In the Silencer you already see the "audiophile touch" - great looks, most money put into the fancy cosmetics - we are so accustomed to.
However - you get 98% of the performance with a Vibraplane for 20% of the money. Proofing again the principle of Pareto (even more here...).
The point is not, whether to use a Halyconics, Minus-K or Vibraplane or a custom made solution. The point is to understand the issue and to fine-tune the solution to the precise needs.
But the main point is - to do it.
Or in philosophical terms and phrases:
Either Descartes: cogito ergo sum...
or J-P Satre: to be is to do .....
or rather Frank Sinatra: schubi-dubbie-doo......... |
|
Dear Dertonarm,
I see your point very well, if someone will invest the money i´d rather like watching the race between active and passive isolation by myself - just for interest.The question remains if it is worth the investment. Nevertheless you also know the famous words: no risk no fun...
or: believe what you hear
or: trust your good friends |
Dear Thuchan, see whenever possible I look for the option which does involve the least periphery and as few parts which can actually fail. Thus bringing the meantime before failure as well as the percentage of possible failure to the minimum possible.
All this of course with equal performance. In this particular matter it all comes down to low resonance frequency and high damping - no matter whether active or passive. |
"We will never see a lightweight TT nor an unsuspended one, with a platter less than 30-50 lbs coming anywhere near the point of closing the book on TT nor approaching its true frontiers.
As we all will see - as they will come and go in half years turn.
The same they have done so for the past 40+ years in high-end."
You misread my comments - my turntable is the Final Audio Parthenon - 25kg+ platter, massive bearing and composite gunmetal rigid plinth and armboards, along with massive motor using power regeneration and power amp for the motor. If you do a search on the net you will find that the top brinkmann's etc are still catching up to my turntable which was built in the 70's. Final used to "upgrade" the big micro's as well as build their own turntable. I dont like the SP10 mkiii just said it was the best dd I've heard. And yes I've had the air bearing tables, arms and moved on. I seem to be sensitive to speed stability, timing and compression - dont want a rose tinted front end with timing issues. |
I am familiar with the Final audio products - and with the Parthenon.
As for "timing" and speed control. My table runs with the big Studer Capstan motor with regulation and Studer speed control. This was good enough for the majority of the music recorded from the 1960ies to late 1990ies. So the stability of the "timing" on most of your records was determined by this very motor drive and its control board. I always found this a most suitable solution.
Especially so as it makes all other TT-motors look like lightweight dwarfs.
As for air-bearings ... well, there are air-bearings out there quite different to the ones "usually" seen in high-end audio. Its all a matter of "thinking in different scales".
And - its not just you being "sensitive to speed stability". Everyone with a remote interest in piano music will gladly join in. |
Dover, what are the specifics of the motor and speed control? Low or high torque? AC or DC? |
Response to Aoliviero
Motor is AC, large ( weighs around 10kg in gunmetal case ), driven by what is described as an oscilater preamplifier, this has sine/cosine outputs, feeding a power amp of which the outputs go back into the preamp and out to the AC motor. The controller has separate infinite speed adj for 33/45 and has a torque control so you can adjust it.
Dertonam
What turntable/arm/cartridge are you using. Is it the one you built yrs ago and described in various threads ? |
Dover, my tonarm/cartridge is silver-wired FR-66s/B-60 w/FR-7fc special. I am currently re-designing my initial TT from the 1990ies. It will be finished late this winter. I will post pictures and a description when finished. |
Dear Dertonearm, I hate to harp on this issue, but I have a "thing" about bad science, such as your contention that the mass of the slate is a major determinant of the distance that a billiard ball will travel (and your bogus reason for saying so). I have done some reading on the physics of billiards, as a result of my consternation. Two things emerge from my research: (1) Once the ball is struck, the major contribution of the table to the distance and direction in which it travels is the static and rolling friction between the ball and the felt, as I surmised in the first place, and (2) slate is used for billiard tables not for its high mass per unit volume but because it can be worked to achieve a very flat surface, and once made flat, the surface of slate is very stable as regards humidity and temperature, i.e., it does not warp. Here I offer a reference to a pretty nice article I found on the internet that reviews the Newtonian mechanics of billiards:
http://archive.ncsa.illinois.edu/Classes/MATH198/townsend/math.html
Now if you can concede that your metaphor is ill chosen, perhaps we can also open our minds to re-examine the idea that platter mass is the sine qua non of the highest end turntables. If I could find an article that addressed your other bald statements, that a certain platter mass is needed, regardless of the drive system, and that the dynamic mass of the Saskia platter does not count as "mass", I would post those too. I don't have the requisite experience to disagree; I just don't think you have the "data", even of the subjective kind, to back up those two notions. The only defendable fact here is that YOUR turntable, which is a belt drive of a certain type and construction, sounded best with a platter of a certain minimum (high) mass when auditioned by you and your colleagues. (I don't know whether you made measurements of frequency response or speed stability that could be adduced to strengthen your case as regards your turntable, but if you did, I would be interested to see same. I am assuming your conclusions are based on subjective listening tests.) Now I can go bang my head against the wall, because my favorite football team just once again pulled defeat from the jaws of victory. |
Sorry, here is complete URL:
http://archive.ncsa.illinois.edu/Classes/MATH198/townsend/math.html |
Dear Lewm, dynamic mass of a TT is certainly important, as it adds considerably to its inertia (and is thus a matter too of the "geographical" dispersion of that dynamic mass in the horizontal distance to the "eye of the hurricane" - i.e. the bearing center), but in absolutely no way it adds to the mass "seen" by the record or stylus.
Why ?
You are standing on planet Earth - right?
Whether our planet spins or not doesn't alter its total mass.
Especially not the difference in mass between you and mother earth.
Now - if you jump from firm solid rock ground it will be different as if you'd jump from a suspended wooden floor and the landing will be different too - right?
Do I need to say more ?
I know that there are very few "physical facts" in audio life were audiophiles can agree upon, but can we agree on that? |
Dear Lewm, again - ALL OTHER FACTORS are identical. Force vector of stroke, felt, air, humidity, everything except the thickness of the slate.
This elaborate analysis you found is what it is - a nice mathematical analysis of the forces, speed, impacts and angles occurring during billiard. It has nothing to do with the model we are talking about.
On the other hand I am certainly on no mission (as I do not believe in missions at all..) to convince you or anyone else.
If you do not agree to that model and to that principle of static platter mass and its contribution to undistorted tracking on the record you have a) a good large party on your side and it is b) totally fine with me.
As I mentioned before - just forget my silly ideas and model, don't bother anymore and continue as before.
Neither you nor anybody else have to accept nor buy that idea.
I certainly have no problem, but simply want to repeat one last time: ... ALL other factors (including the felt..) in that model are identical (just think about this for a moment - it tells the whole story - factor-elimination! - and it requires far less time than looking for written papers via Google......).
For your consideration - the increased thickness do bring one other factor into the "game" which too does contribute to the decreased tracking distortion as well as to the "longer run" of the ball on the table (and you won't find that covered in the maths either.....). But it makes little to no reason to discuss the next point when the first factor is still clouded.
Well, - I was used all my life to think and act far away the mainstream.
You do not find fresh grass (neither for your cows nor for your racing horses... ) if you walk on paths and grounds hundreds have walked before. |
Dertonarm, Lewm, Dover,
I have been pondering the technical aspects behind TT speed stability in a qualitative way. I think there might be situations where mass plays an important role. I tend to think about this as AC vs DC, low vs high torque, low vs high platter Inertia (driven by mass). I tend to bracket in the following fashion:
1) Optimum
a) low torque, high platter inertia, AC
b) low torque, high platter inertia, DC
2) Moderately optimum
a) high torque, high platter inertia, AC
b) high torque, high platter inertia, DC
3) Not so optimum
c) high torque, low platter inertia, AC
d) high torque, low platter inertia, DC
e) low torque, low platter inertia, AC
f) low torque, low platter inertia, DC
What Im basically trying to say is that a high mass platter may be able to ride out or sustain small speed instabilities introduced by either the motor or drag from the stylus/record interface.
I wonder if a high torque motor combined with a low enough platter mass begins to dominate speed instability in case there are speed instabilities in the motor. In other words, the platter inertia may not be high enough to dampen this effect if the motor torque is the dominant factor.
I would think that the low or high torque options with low mass option may be the worst.
I also wonder about AC vs DC motors. I heard that while AC motors are constant speed, DC motors are actually constant torque.
Any thoughts on these questions? |
Dear Aoliverio, while I will not question the ranking you have listed, I would nevertheless like to mention, that it too depends on the transmission (belt, string, tape - whatever). Introducing a low grip string/thread with a certain "amount" of "wanted slip" then the first group with high mass platter/high inertia will display an extremely smooth and constant speed with little to no measurable derivation once 33 1/3 are obtained. The higher the inertia/mass and the lower the grip of the thread the more constant the speed. I would call this the "Micro-Seiki-RX-Principle" as it first was introduced and widely used by Micro Seiki with their RX-series of turntables. Furthermore the thread with low tension/grip is about the very best "isolator" from motor/flywheel generated vibrations.
As for the motors - in the set-up with low tension thread and high inertia their importance is decreasing. I simply choose the best capstan motors and stop worrying about the issue at all. An expensive, heavy and uninspired choice, but a very satisfying and final one too.
However - the more rigid the coupling between platter and motor and the less mass/inertia in the platter the more importance in the speed stability and low vibration of the motor drive.
Here again I would choose a really good big tape machine capstan - for the very same reason as before: stability of speed, very little vibration.
What we find on our records was recorded with these capstans in big Amperex and Studer machines for 4 decades.
I think if it is good enough for the source of our records, it is good enough for their reproduction. |
Dertonarm
You make a very interesting point which may help explain some observations I had with a previous system.
In a way I was thinking about low torque as a way of minimizing a motor speed instability on the platter. I think you are right that some wanted belt slippage would accomplish the same thing. Possibly better.
Couple of comments. Would the belt slippage concept work the same with a DC motor? If these are constant tourque, would the motor try try to compensate for slippage and therefore lose speed? Whereas an AC motor being constant speed would not change pulley speed if the friction changed due to slippage.
Any thoughts? |
DT, you wrote,"Now - if you jump from firm solid rock ground it will be different as if you'd jump from a suspended wooden floor and the landing will be different too - right? Do I need to say more ?" You might say more about the relevance of this metaphorical and rhetorical question to turntables. But don't bother on my account.
Aoliviero, There is no free lunch. Each of the common mechanisms for spinning a platter has its particular set of compromises, including high mass platter/loose belt types. If you really want to learn more about it, go to Vinyl Asylum and search for the posts of Mark Kelly on this topic. He has done real experiments, and he can back up his conclusions with physics. Don't get nervous, DT, he likes much about belt drive turntables, but not the whole enchilada. |
Aoliviero,
You said...
"I have been pondering the technical aspects behind TT speed stability in a qualitative way. I think there might be situations where mass plays an important role. I tend to think about this as AC vs DC, low vs high torque, low vs high platter Inertia (driven by mass). I tend to bracket in the following fashion:
1) Optimum
a) low torque, high platter inertia, AC
b) low torque, high platter inertia, DC
2) Moderately optimum
a) high torque, high platter inertia, AC
b) high torque, high platter inertia, DC
3) Not so optimum
c) high torque, low platter inertia, AC
d) high torque, low platter inertia, DC
e) low torque, low platter inertia, AC
f) low torque, low platter inertia, DC..."
I agree, but believe the absolute details of it are somewhat determined by the drive implementation and other factors that may be specific to a particular design.
Win
Saskia Turntables |
Dear Lewm, well - as I mentioned before - there are many audiophiles and "audio scientists" out there who do favor direct drive or idler drive in turntables ( both principles do build on the idea of "control" and the motor and its quality has a huge impact on the result) and who will present wonderful technical descriptions and "proofs" for their preference.
But that is not my problem. I do use thread/string drive with very low grip and "wanted slippage" to accomplish what I want and use extreme high mass and inertia to get to a kind of self-stabilizing system. This has one huge drawback: - a fairly long time to get to the needed speed.
I am using a motor which is extremely expensive (and weights 12 lbs without any cover ... raw) and would by the way qualify easily for the most demanding ID or DD TTs.
I have told you in a direct email what are the points behind direct drive and idler wheel drive and their origins and original purpose.
We will see all 3 drive principles in various versions side by side for the next decades. Every one of them will have their cheerleaders and followers.
Fine.
No worries Lewm - I certainly will not get nervous about anyone's experiments. I have done my own. Too many people do misinterpret their dreams, philosophy or ideas for physical facts. And any experiments result is depending on its conductors ability (or his will...) to read it and draw the (sometimes unpleasant...) objective conclusions. |
Dear Aoliviero, the Studer capstans I worked and work with are all AC. In this model it is all about constant speed of the motor spindle/pulley/flywheel.
I see your point. A motor trying to compensate slippage by altering speed is of course a contradiction for the slippage concept.
In general - this concept is kind of tricky to set up and works only with certain TT's (platter mass...). It works with thread/string NOT with belt. It works best (as all drive principle in TTs) when the horizontal plane of the bearing is force free. The actual "embracement" of the thread around the platters diameter must have a pretty large angle - 210 degrees and more.
It not easy to fine tune, but once done it works smooth and reliable and gives extreme constant speed with ease. What I always liked particular about this model was the "natural touch" - letting inertia doing its work undisturbed.
Nice. Quite the opposite of the "control" approach. |
The recent threads suggest that maybe the way to segment this better might be in the following camps:
1) Strong coupling to platter and strong control of plater speed
The direct drives would fall into this camp. As would most belt drives that have strong connection to the platter.
I would think that either low or high mass platters can fall into this category with high mass being better.
Either low or high torque with higher torque being better when trying to control a high mass platter with belt.
Either DC or AC with speed stability playing the more important parameter independent of motor type.
I would also think platters with purpisely hgiher friction bearings or eddy-brakes would have to fall into this category.
2) Loose-coupling to platter, use of platter inertia to maintain stability
This would need to be a string-based drive with enough slippage. Obviosuly, direct drives would not be present since there is direct motor coupling to platter.
I would think you would need to use an AC motor or the like since it is a constant speed device and would not change spindel speed if there is slippage.
I'm not sure if torque would matter for an AC motor.
I think one would defintely need the high platter mass in this case to maximize platter inertia.
I would think that a more freely spinning, "friction-less" platter would be better than something that is helb back by a large bearing friction or eddy-brake. But then maybe a certain amount would be okay?
Anyway, would seem that the number of turntables in camp two is smaller. Forsell? Acoustic Signature? Platine? Custom units?
Andrew |
Yes, the "camp two" is considerably smaller. You may add to that short list the big Micro Seikis, Final Audio, Epic and Melcos of decades past. Than the german Apolyt from the 90ies with so far 15 units built and featuring the most extreme and most expensive approach of this principle. The classic Platine Verdier however does feature eddy-current brake (side effect of its vertical magnetic supported bearing) and is used today by various owners with all kinds of DIY-drives (I have seen idler-wheel driving PVs as well as tape, belt, thread and even transmission belts).
Cheers,
D. |
D.
So you prefer belt/string over any other method, so.
With anyone here the sound you get or strive for serves your own sonic interest and adjectives.
I use one belt drive table and one refurbished direct drive table. I prefer the dd, silly cheap compared to the belt drive.
lastly a question for Dover, what do you think of someone dumping a Walker Black Diamond for a refurbished Technics SP10 MKII ?????
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The original topic was, "Upgrade from TW Acustic Raven AC-3 to what?"
That is the proverbial can of worms, isn't it? We can sit here ad infinitum, and discuss the merits of this or that implementation, but at the end of the day the user wants to improve upon the turntable that he currently owns. That turntable happens to be a very well-respected one, so his choice is likely to be another that is built with equal passion, but its builder will be acting with a different vision of how it should sound. The bottomline is that the implementation of the vision should be in keeping with the buyer's expectations. He wants a different sound that more closely meets what he feels is right for his particular system.
It isn't about technical merits at this point. Rather, it is more about choices that meet personal criteria because he already has a top-flight turntable.
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Stiltskin, Be prepared for a lecture.
Mosin, I was thinking along the same lines. In fact, Alectiong may have already made his choice while we've been carping. I am very curious to know what he bought, or maybe he wants to sell his Raven/Grandeeza first. |
