Dear Dertonarm, Dear Syntax,
You have " a schöne Rücken"
best @ fun only |
it is very funny, the DD-drive concept divides the users in two seperate fields, lovers and deniers, as sometimes happens with the idler drive as well. From my experience with DD drives I am convinced that a DD motor needs a perfect environment (sorry Halcro). There are excellent examples of "very musical drives", e.g. the Technics MKIII in a fine plinth, the Nakamichi (Micro Seiki motor) or the Brinkmann Oasis.
I found an interesting description at Brinkmann maybe with relevance to the speed/time issue:
The drive mechanism is probably a turntables single most important component. This significance results from the fact that music consists of sounds organized in time. A turntable therefore has to play back a record at precisely the same speed at which it was cut, normally 33 1/3 or 45 rpm. Any deviation, no matter how small, from the correct speed will ultimately change pitch and tempo and result in music reproduction that is not true to the recording.
Our hearing is much more sensitive to short term speed variations, as opposed to long term ones. The onomatopoetic term wow & flutter correctly identifies the underlying issues wow describes continued, longer lasting deviations, caused for example by eccentric records, whilst flutter denotes short-term irregularities best demonstrated by piano tones that fade away with a slightly howling quality.
Let us consider the following example: a 1 kHz tone (1000 cycles per second) is cut into a lacquer at precisely 33 1/3 revolutions per minute. If the pitch is to be accurate, the turntable has to play back this tone at exactly the same 33 1/3 revolutions per minute. A seemingly insignificant variation of 1% would result in a playback speed of either 33 or 33@d revolutions per minute with pitch being off by ±10 cycles. Even people with perfect pitch would have a hard time correctly identifying a 990, 1000 or 1010 Hz tone without a reference yet even brass ears would easily hear the differences in a direct comparison.
Speed precision is perhaps even more important for the musics tempo. For our perception of music to be real, the tempotiming and paceis more crucial than the pitch. This is where the 1% difference would make itself heard far more easily. Considering that a typical record has a playing time of around 20 minutes per side, a ±1% difference would amount to no less than 24 seconds. This seemingly irrelevant deviation would result in either a slightly restrained and darker sound, or a livelier, brighter reproduction of the original event.
In order to meet the claims of High Fidelityno more, no less than music reproduction true to the original the cutting and playback speed have to be absolutely identical. Due to reasons being outlined in the following pages, this theoretical ideal is practically not feasibleturntables are hence (and in the best case) the closest possible approximation to the theoretical optimum.
Two elements determine the rotational speed of an AC based electric motor: the power line frequency and the number of magnetic poles. The formula used to describe this is as follows: rotational speed = line frequency x 120/number of magnetic poles. In countries with a 60 Hz power grid, a two-pole electric motor therefore runs at 3600 rpm (60 x 120/2 = 3600). Each doubling of magnetic poles cuts the rotational speed in half: 4 poles equal 1800 rpm; 8 equal 900 rpm; 16 equal 450 rpm. Theoretically this could be continued even further, however, practically, there are only so many poles one can fit inside a motor case.
Further, each additional pole also increases the motors torque, which in turn increases the cogging effect. DC electric motors dont fare any better either and most are offered in standard 1500 rpm configurations. This showcases the ensuing problem quite easily: on one hand we have an electric motor spinning at 1500 rpm, on the other we have a platter which has to spin at 33 1/3 rpm. The ratio of motor to platter speed is therefore 45:1. Logic dictates that the drive pulley has to be 45 times smaller than the platter.
If we take a platter diameter of 30 cm as an example, this would equate to a pulley of only 6.6 mm in diameter. The contact area for a belt is therefore very small, which in turn increases slippage; which in turn influences speed stability negatively. The problem is further exacerbated by the fact that the cogging is transformed into a frequency range in which human hearing is very sensitive
The power line frequency (and thus the motors rotational speed) can be reduced with frequency converters; however, the cogging problem still persists.
The platter of a turntable can either be driven directly or indirectly. In case of an indirect drive mechanism, platter and motor are two separate components whereby the power from the motor is transferred to the platter through intermediary means. In case of a direct drive turntable, platter and motor are assembled into one and the same unit.
Motor and platter are two separate entities; some sort of medium is necessary to couple the motor to the platter. Typical applications include the following:
> Belt (round or flat; geared or v-belt type; various threads made of synthetic or natural fibers)
> Idler wheel
> Gear wheel drive
The choice of transfer medium is critical since it not only transmits the motors torque to the platter but also all motor-based interferences, among them the motors cogging, which compromises speed stability since the platter is not driven continuously but somewhat jerkily instead. The more direct the connection between platter and drive, the more directly these interferences will be transferred. An idler wheel for example couples the motor very directly to the platter. As a result, the cogging effects are more pronounced; in the best case they manifest themselves as a slight flurryness of the sound; in the worst case through clearly audible distortions.
Because of the reasons stated above, most turntable designers therefore prefer a softer coupling between the diameters of the motor pulley and the platter. Even tiny discrepancies in the belts uniformity will have a serious impact on the platters speed stability. Consider the following example: say a DC motor running at 1500 rpm drives a 20 cm sub-platter via a 1 mm thick flat belt. A discrepancy in tolerance of only 1/100 mm will have a net effect of 0.9% wow & flutter on the platter!
Countering these effects demands substantial efforts in the design of a belt driven turntable. Heavy platters (12 kg or more) and low rpm motors tend to mitigate these side effects to the point of not being significantly audible.
Studios (radio stations in particular) demand quick start-up times turntables typically have to reach their correct speed within half a revolution. For LPs this means 0-33 1/3 rpm within 0.9 seconds. Such acceleration figures can only be achieved through use of high-torque motors and correspondingly tight coupling between the drive and platter. It isnt a surprise then that for decades idler wheel drive designs were the de facto standard in studio applications.
But idler wheel turntables also had seriously high maintenance costs in order to be up and running 24/7 and to avoid rumble and other sound degrading issues caused by worn out idler wheels to affect the sound negatively.
Thus out of necessity, in the late 1960s manufacturers of studio turntables began to look for
low(er) cost maintenance alternatives. They came up with direct drive, whereby the platter was placed directly on the motors shaft, ie the stator was mounted around the bushing and the shaft was used as the rotor and voila, the goal was achieved; at least in theory.
But start-up times of less than 1 second necessitated high torque motors, which designers achieved byusing motors with 32 and more poles. The penalty they paid were heavy cogging effects accompanied by high wow & flutter numbers. The cure was found in quartz locked motors and phase locked regulators; which corrected for any deviations from their preset with an iron fist.
On paper at least, these corrected direct drive turntables boasted hitherto unimaginable low wow & flutter numbers down to 0,001%. But the rigorous iron fist regulation prevented the platter from spinning smoothly; instead, the regulation caused the platter to oscillate continuously between speeding up and slowing down.
These start/stop motions translated into an unpleasantly rough and hard sound; odd as wow & flutter numbers in the 0,001% range are deemed inaudible. Once the direct drive technology had gained a foothold in pro audio applications, the benefits of mass production (ie. trickle down effect) made sure that very soon even $100 turntables were equipped with direct drive and advertised as having less than 0.01% wow & flutter. This is precisely where direct drive got its bad rap sheet.
Under closer scrutiny however, this assumption were based on some misunderstandings. For one, in home audio application use, turntables are not really required to reach 33 1/3 rpm in less than a second, thus 32 pole motors and phase locked regulators are not really necessary either.
Finally, one more relatively unknown factoid: while it is common knowledge that direct drive turntables became popular in the late 1960s, their actual invention dates back to a small Swiss manufacturer in 1929. The name? Thorens, who enjoyed and even today is looked upon with great respect for their idler wheel and belt driven classics. |
I heard about an audiophile living in Munich who usually proudly presents his very rare and expensive vintage items, including high calibre turntables. During a listening session someone stated "the sound is so slow, maybe we should check the speed accuracy". The result was 30,.. also being not very stable.
Speed was corrected to 33,33 and in the end the audiophile resisted listening to the correct speed sound. He said, I am used to the slower mode, it doesn`t matter if anything is correct. I love the sound!
Oh my god...
Best and fun only |
Dear Unoer,
my system does not stand in Munich - if you were thinking this direction :-)
I just made a test with the Timeline and the VPI SDS - and indeed it was running a little to fast when using another tonearm (in this case Micro Max 282 with Sussurro).
Slowing down with the SDS is just precision and fun !!!
BTW I also like slow food, slow life but sometimes fast driving :-)
best @ fun only |
Dear Unoear,
(why not Duoear ?) you are fully correct. It is not a big problem finding me if you are not restricted to the US as some people seem to be, like Audiofeil for instance. Nevertheless this guy knows all kind of ice cream tastes and National League players (of the US of course) - hmmm maybe interesting.
But back to the topic. Has anyone really opened the Timeline and do you know what this means? Did you count the screws Halcro?
Unoear is a nice acronym. Is Duoear still available :-)
best @ fun only |
Never tried the Timeline with the Criterion because the air damping asks for a record fixing knob over the spindle of the platter.
I may try without the special fixing tool.
best @ fun only |
Dear Geoch,
pls. give a warm hello to Chris Skaloumbakas. He will remember my "Greek Membership".
best @ fun only |
Hey Geoch, Nandric is right. You will definitely get a good price in the German market for your TT. I have seen one in an exclusive High End shop recently. They sell it as a Brinkmann Project.
I would rather go on ebay, maybe ebay.com than on Audio Markt. At Audio Markt you will be confronted with lots of stupid questions. No need for this experience.
Best @ Good Luck |
Tonywinsc,
interesting what you experienced during your test measurements. on all my TTs I experience a change in speed when the needle hits the record. Regarding the different carts and weights of the headshells I usually adjust speed by my speed controllers. Belt drive not necessarily needs to be a disadvantage (thread). I usually measure my wow & flutter with a test tone of 3150 Hz and on the EMT by 5000 Hz (J60s).
You are so right on the Influence of the exact spindle position of the record. Most turntable designs don't refer to this issue. I know one design which does optimise the center of rotation - the Nakamichi TX 1000.
Best @ Fun Only |
Halcro,
do you have an inbuilt realigning control unit which brings the speed always to 33 or 45?
best @ fun only |
Perfekt Henry!
What is the name of the red lamp fixed in the wall?
best @ fun only |
Henry,
you made a good point with the Timeline & the Nakamichi. The red signal keeps stable even when the needle runs down on the record. Ths is an advantage of the DD design (and I have to correct myself - no manual speed correction is necessary on all my TTs).
Tonywinsc,
if we start a competion by using a stopwatch I might win with the EMT ;-)
Frogman,
you are right, precision control is the one thing but musicality and a sonic footprint is the other one. Therefore I find it hard always following the neutrality apostles in our community - but there are not so many in this thread. Am I right?
best @ fun only |
well said Frogman, but I am not pairing sonic footprint and neutrality. Sonic Footprint in my understanding is that you recognise the turntable's abiliy in producing fine music. Just take the EMT R80 (927) as an example. Agree completly that Precision Control allows musicality. I for myself need both!
Some people argue that a turntable should just reproduce which is a funny statement. A Linn Lp 12 and some of the smaller new Thorens tables e.g. also reproduce - but with what kind of result. Of course some people may like it. good. Distortion is a wide field and I know someone in this community who loves the term.
In my understanding sonic footprint is not the result of distortions at all. The Nakamichi, or the EMT as well as the Micros do have a sonic footprint which is different. Does this mean I am surrounded by distortions, God beware. I would jump from the bridge...
best @ fun only |
Dear Lewm,
ok didn't jump so far. Maybe I have a different / not typical understanding of footprint or better let's say character or personality of a turntable.
I know some audio gurus carry the philosophy of neutrality around the world, which should mean, the more neutral a turntable is the better for the reproduction. In their sense it is absolutely necessary that a turntable should not become musical - but neutral. A neutral turnable cannot be musical, warm or dynamical, or lively. It is and has to be just neutral. Everything else is coloration or distortion. Am I right? Okay. In this understanding I am happy to live with coloration & distortion - and I don't need to jump.
best @ fun only |
Dear Raul,
I know about the theoretical discussions you are referring to and so many people in this business. Regarding practical issues when it comes to listening it is not about the turntable adding something or not! This is not my point. You may bring down a turntable to neutrality and it sounds shitty or let's say clinical cold.I have heard so many totally neutral turntables and the owners were proud of their sound. Fine. The real art in turntable building or let's say also in dealing with different concepts/drives and comparing those is based on the ability of the turntable to transport the signal in an uncoloured and undistorted way - which does not mean that all turntables doing this are equal or coming with the same sonic footprint (!).
When you ever had the chance listening to an EMT 927 or to a very good DD or to a brillant belt concept ( lets take the Continuum as an example ), and I am sure you can, you will agree that although they are playing music in a wonderful way, they offer some differences. From my point of view it is the biggest missjudgement to put these differences (dynamics, musicality, bass grounding etc.) only to artifical add ons which should not be there.
Some people don't like the sound of idler wheels.I believe it is good listening to a well adjusted idler wheel. I have experienced the differences also of various prominent brands and models, good sounding and not good sounding idler wheels. An idler wheel can be very dynamically. Is this generally coloration or distortion in your definition? Or are you referring to not well adjusted tables - which is different.
If for example a SME is an absolutely neutral turntable in your or other people' s experience and you regard the sound it makes as a benchmark "in your undistorted world" perfect! For me it is not benchmark! But this is up to the preferences one has. I am sure we both must and will live with our different way of approaching practical listening experiences. What I am saying is: Too much in this forum is only and more or less theroretical based. Maybe we can bring some colour into it :-)
best @ fun only
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Dear Syntax,
you are saying speed stability has nothing to do with sound quality. How do you mean this? If the speed is varying enormously during the playback process it leads not only to deviations in wow & flutter but you can also hear an impact on the sound, I mean I can hear it. And I believe you do too !?
best @ fun only |
Peterayer,
I could not find the Wave Kinetics thread anymore too? Sometimes it happens that a thread disappears by accident. Do you have some information? You suggested this new wonderful thread.
best @ fun only |
Deartoenarm,
agree with your preconditions being set. Unfortunately the reality regarding some running tables looks sometimes different due to weak motors, belts changing the consistency, no built in or used precison control instruments etc. The new TechDas AirForce seems to offer some nice features. On the other hand I would have wished a two sided belt driven system.
best @ fun only |
Dear Nandric,
it is an ongoing quest. I am happy that some new designs appear on the horizon and that Micro Seiki seems to be back.
Maybe we will not see only clouds in the future...
Best @ fun only |
Speed accuracy has inspired two more companies bringing out devices for checking. Allnic with the SpeedNic turntable speed checker and Dr. Feickert's free Platter Speed speed check software (for i Phone or Android) - learning from MF...
best @ fun only |
Dear Lewm, disagree. I think they read the posts but they understand it in a different way as you, me or others do.
This is not because they not only have a more sensitive scope but maybe they have a more sensitive feeling too when reading each other`s post.
Nevertheless I do think in this topic we are all not far away from each other. We all agree that accurate speed is an important condition or precondition for enabeling a good sound quality.
Of course there are other factors having also an impact on good sound quality, the bearings quality (e.g. air based or other quality attributes), the motor´s quality (maybe also fly wheel or more motors), the platter`s quality (material, weight, air lips) the belt, thread or idler wheel`s quality, and last not least the interference and the implementation of all these turntable parts. Enough stuff for some more threads...
best @ fun only |
when it comes to bearings/ motors and platters I see a difference between the vintage designs and most of the modern turnables. The service principles say I need to lubricate the EMT' s bearing every year, oiling the motor once in years. Introduced in 1951, the EMT 927 is a massive turntable with an aluminum chassis, meassuring 6 7. 5 x 52 x 21 .5 cm with a weight of 80 pounds. The platter has a diameter of 44 cm and sits in an amazing precision ball bearing. The bearing shaft is 16.6 cm long and has a diameter of 2 cm! The motor itself is massive. It looks like an industrial motor, 13.5 cm in diameter and 20 cm long! It is a 3 phase synchronous type with phase shifter.
The big MS designs have an oiled, capsuled bearing which should keep a man's life. The massive platters have a weight of 40 to 50 pounds, the full table up to 170 pounds. The Micro Seiki motors are very precise (with a competent controller) as the Continuums motor is as well, a linear 3 phase AC-24V DC Brushless design with integral optical decoder. You need looking at these parts to get an understanding why the usual small motors used for todays TTs are a joke! The Continuums platter has a weight of 60 pounds. I have put an image of the self lubricating bearing on my page to show the difference.
I do understand when Dertonearm questions the quality of new developments against the Micro Seiki, EMT or Continuum standards. In all the mentioned designs the mass does its job with inertia and resonance control. All that makes for a very good turntable in my opinion. And in all designs precision is of importance.
best @ fun only |
The Allnic SpeedNic works pretty well. I have put two images on my page (last two images when scrolling down)
best @ fun only |
Dear Halcro, you´re right the Timeline is perfect. The Allinic provides the advantage you may use it as a fixed installation and you do not need to hit the mark at the wall which is a bit of trial and error moving the Timeline forth and back - but of course after a while it works brilliantly.
You have two turntables and only one strobe - this looks like an imbalance :-)
best @ fun only |
Dear Lewm,
the Allnic SpeedNic is battery powered and not so bad as you think...
also it allows adjusting during play.
I am not selling this product :-)
Rugyboogie,
you are in very comfortable situation with one running turntable ;-)
best @ fun only |
Rugyboogie, I meant with one belt drive TT, sorry!
best @ fun only |
Dear Peterayer,
Do understand. Sometimes threads are dissapearing without the community being informed for what reason this was done, if it happens accidentically or because someone asked for deletion. In my case I asked Audiogon. on one thread it was restored, on another thread I did not get any reply, maybe a dealer wasn't` happy - just wondering ...
Best @ Fun Only |
Ketchup,
TT bearings of the 50is are bigger, more stable and usually in good TTs of a much superior built quality than those of most modern concepts.
best and fun only |
Dear Lewm,
Yes it is Exactly as you described. Modern manufacturers have better toolings and usually better preconditions but most do not make proper usage of it. Continuum is a positive exception. Nowadays high quality bearings seem to be too expensive which means we are offered more and more crap.
Best & fun only |
