From Jfrech's post about the Grand Prix Monaco: "A highly accurate test procedure has demonstrated the speed error to be an extremely low .002%! Speed accuracy equals frequency accuracy, which means there is virtually no distortion on playback." Is anyone else wondering what their highly accurate test procedure is? |
Peterayer,
I wasn't including you amongst those who have said that a very high-mass platter on a string or thread-drive turntable would be immune to stylus drag as you have admitted the fact......
Dertonearm and Dover I believe in the past (amongst many others previous to the advent of the Timeline)....have made such claims.
Yet I have shown on my video of the Raven AC-2....the comparison when the stylus is NOT in the groove and I think that that gives a further comparison to both the motor, belt/string/thread and platter abilities of a belt-drive turntable......or ANY type of turntable.
Your comments (and Syntax's) about only being concerned by the performance when the stylus is tracking the record....is misleading.
I have recordings that have extremely modulated grooves and I have records which have very benignly modulated grooves.
I can adjust the motor controller to handle one or the other.....but unless the speed is manipulated for each and every record you play.......there will inevitable be a difference in the Timeline between different recordings.
This is why seeing the Timeline 'without load' in comparison to 'under load' is valuable. |
Dinster,
I have the Feikert App and the 10" Test record to go with it and have done repeated testing on both my tables using my iPad and posting the relevant print-outs.
The important thing about scientific or objective testing...is 'repeatability'.
In other words....every time you or I proceed to test exactly the same thing....we should achieve exactly the same result?
With the Feikert App.....I achieved different results every single time I repeated exactly the same tests?
In some cases...the results even showed the Raven AC-2 giving better results than the Victor TT-101? :-)
The test record itself was a major part of the problem.....
Due to the fact that it contains a modulated groove of exactly 3150Hz....it is essential that the record hole is dead-centre.
This is simply unachievable to the degree necessary to avoid variations from that constant test tone.
With the Timeline......every test result is repeatable.... |
|
Halcro
Agree it would be nice to have consistency in the test methods.
HF Dover
Phase lag is a result of drag, not a cause of it. |
01-08-14: Richardkrebs
HF Dover
Phase lag is a result of drag, not a cause of it. Yes, phase lag COULD be a result of stylus drag, but not necessarily exclusively. As a matter of courtesy, I would ask you to address me correctly as "Dover" which is my name on this forum. |
A DC Motor is a simple device. The speed is proportional to voltage input and load. If the load increases then the speed will drop and current will increase. My Sota tt has a simple power supply and DC motor. It has a trim pot for fine tuning speed; but speed will vary as load changes. (A tt with closed loop controller for a DC motor would vary voltage to maintain speed under varying load conditions.) Using the iPhone app I can adjust the speed to within 0.02%- about an order of magnitude off compared to Peter's SME deck. Also, speed drifts on my tt as it warms up so I must let it run for 15-20 minutes before fine tuning the speed. I know the higher end Sota tt's have much more sophisticated motor controllers. I would like to know how they perform in comparison.
Synchronous AC Motors are based on frequency. The rotor of an synchronous AC motor is always following the rotating magnetic field. That is phase lag or slip as Richard mentioned. As the load on an synchronous AC motor increases, phase lag increases. Current draw in the motor will increase which increases torque in order to bring the phase lag back to near zero. The frequency source for a synchronous AC motor can come from the 60Hz AC line or from a seperate frequency generator. Voltage will not change speed on a synchronous AC motor but it will change the amount of torque available to minimize phase lag. (More voltage means more current draw is available.) A closed loop synchronous AC motor controller must vary frequency to adjust speed. |
Halcro, My test record that I use for the iPhone app is also flawed. The record hole is off-center so I filed the hole open a bit and I must center it as best as I can on the platter. I get differing Wow&Flutter measurements (between 0.06% down to 002% filtered readings) depending on how well I center the record. My record also has a slight warp and at around 12 seconds into the track the frequency shifts due to this warp. So my overall measurements look better when I start the recording past that warp. I did screen saves on sevaral measurement trials using the iPhone app and finally saw this pattern of speed or frequency shift at the same point every time. |
Halcro, that new Victor TT-101/3 arms video is quite impressive. My belt
drive could not do that. I do see the value of testing with and without the arm
being in the groove. Unfortunately, my Timeline is gone so I can't retest or
shoot the video.
Your latest video seems to have much less drift than the first one (with 3 arms
but no music) linked in the OP. I wonder why that is. The drift to the left in
the first one looks like half the length of the Timeline dash so I guessed it is
3/8". The latest video drifts much less, but from about 3:15 in the
video to the end, it is clear that the TimeLine dash is no longer centered on
the blue tack but drifts to the left until about 3/4 of it is to the left of center
and 1/4 is to the right of center.
This is very minimal drift over 5 minutes. Perhaps Tony could calculate the
error if you give him the distance from spindle to blue tack and the drift
distance which looks to be about 1/8" or so.
Syntax did post a video of the thread drive Micro. I'd like to see some of the
modern DD tables like the NVS and also the BD TechDas. |
I verbally reported some results I got with my SP10 Mk3, using a Timeline borrowed from my neighbor up the street. (Yes, there are two audio nut jobs living on ONE short block in Bethesda, MD, USA. What are the odds of that?) He was using the Timeline to prove to himself and to me how very unstable was his very high end very expensive belt drive turntable, with a massive platter, I might add. The manufacturer told him there was a fault in his new motor controller to account for his disappointing observations. And now recently the new motor controller and a new kind of belt have been acquired. I don't know what these two upgrades (?) have done to improve his situation. The laser beam was riding around his room so fast I thought we were in a Disco night club.
I've mentioned this before; one problem with the Timeline is that it seems to have been designed for the narrowest of the 3 possible spindle diameters. I found it will not fit on the spindles of my Lenco or my Kenwood L07D (or perhaps it was the Denon DP80). Has anyone else had this issue? Following on the heels of Dertonearm's clever protractor, it would seem that Sutherland could solve this problem by incorporating interchangeable spindle holes, that could screw on to the bottom of the device. Thus, even more vinylphiles could be driven mad. |
Halcro
Ok.., what is the music this time?
Nice
Lewm
I missed your report on the MK3 with the Timeline. Are you able to repeat them here?
Thanks |
Nothing to say except it was bang on accurate, with the laser beam hitting a wall 8 feet away. I did not try a wide variety of music, and I did not persevere for very long once I felt the point was made. Perhaps in 10 minutes of observation there might have been some deviation; I can't say either way. I think I watched the blinking light for 2-3 minutes at most. Then I fell into a "deep sleep" and did whatever my wife told me to do for a week. Eventually, I snapped out of it.
If you're asking whether I can post a video, the answer is that I lacked such a capability at the time, not to mention that I had no such idea, either. I can probably re-borrow the Timeline if inquiring minds want to know. |
The real question is are these very, very small speed changes AUDIBLE!
I seriously doubt it!
Tape recorders and cutting equipment does not have perfect speed in the first place.
Many audiophiles like to split hairs with theory that makes no difference in real life. This is just golden ear BS! |
Richardkrebs - the music you inquired about is Cantigas de Santa Maria #77 - sounds like Jordi Savall - he performs in Auckland from time to time during his world tours. Highly recommended. |
Lewm
8 feet to the wall, that is a tough test.
Don_c55
I understand your skepticism, but would argue that these micro speed changes are indeed audible.
Sure we have tape machine speed instability along with eccentricity problems. That said, speed changes due to stylus drag, which is where this thread has kinda coalesced, are fundamentally different in nature. This because the music itself causes it. This results in a subtle smearing and bending of the notes. A general softening of the soundscape. The effect can be " nice " but it is not what was laid down on the record. |
I would like to again offer my Timeline Calculator Excel file for anyone who would like to try it out. You enter the distance to the wall and the laser deviation per revolution and it gives you the circumference of the virtual circle that the laser travels, the speed error of your platter in percent, the RPM your platter is off by, and the actual RPM of your platter. It can also tell you how many Hz a given frequency is off by. Here's the original thread: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1327029459 |
Don, Richardkrebs is right..... Why is speed so important? As you know, the primary job of any record player, including turntable, arm, and cartridge, is to accurately reproduce the waveform of the music as it was originally recorded onto a vinyl record.
But how exactly is this job divided up among the turntable, arm, and cartridge? Most people would say that the cartridge has the job of reproducing the entire music waveform, and that the turntable and arm have lesser passive roles, merely responsible for being stable platforms for the record and cartridge, so the cartridge can do all the active work, reading the entire music waveform from the record.
That's wrong. The cartridge does not read the entire music waveform from the record. It can't.
Why not? Because the vinyl record contains only half of the music waveform.
Where then does the other half of the music waveform come from? It comes from the turntable. That's right. The turntable is fully responsible for actively supplying half of the music waveform, and the other half comes from the cartridge.
This puts turntables in a whole new light. If a turntable's job is to actively supply half of your music's waveform, then it had better be doing its job right, otherwise your music will obviously and dramatically suffer -- to an extent you wouldn't have imagined when you thought that music's entire waveform came from the cartridge.
What do we mean by saying that half the music waveform comes from the turntable? You know that music's waveform can be plotted on a graph or on an oscilloscope. The graph of a music waveform has two axes, as do most common graphs. The vertical axis represents amplitude, and the horizontal axis represents time. The music waveform needs both these axes to exist, since it is a two dimensional entity in nature. If one dimensional axis or the other were somehow missing, there couldn't be any music waveform, and there couldn't be any music. Music itself is a time bound art form, and its existence depends on the two dimensions of time and amplitude as surely as a sculpture depends on three spatial dimensions (but not on time in the case of static sculpture).
In a record player, the vertical amplitude axis of the music waveform comes entirely from the cartridge. But the horizontal time axis of this music waveform comes entirely from the turntable.
It's like a gentleman's agreement. The record manufacturer actually gives you only half the music waveform in the groove, for your cartridge to read, namely the vertical amplitude axis. You agree to supply the other required half of the music waveform, the horizontal time axis, by agreeing to employ an accurate turntable to play back the record manufacturer's disc. The turntable that you chose to employ literally supplies the time axis half of the music waveform, while your cartridge reads the amplitude variation half (and only that) furnished by the record manufacturer, as the groove is passed underfoot by your turntable recreating the time axis half on the fly.
We give a great deal of attention to making sure that cartridges are accurate reproducers, so that they correctly read the side to side swings of the record groove that furnish the amplitude information about the music waveform, and thereby do not distort the music waveform themselves. But that's literally only half the story. We should also devote equal attention to making sure that the turntable accurately furnishes the time axis half of the music waveform. If we don't, then the final resulting music waveform will be distorted, as surely as if the cartridge were contributing unwanted distortion by inaccurately reading the amplitude axis half in its side to side swings.
The lesson is clear. You could buy the world's most expensive, most perfect cartridge, that exhibited perfect accuracy in reproducing the amplitude half of the music waveform from its side to side swings in tracing the record groove. But, unless your turntable is perfect in creating the time axis half of the music waveform, the final music waveform you hear will be distorted. The right amplitude played at the wrong time will distort the music waveform as surely as the wrong amplitude played at the right time. So Don.....as the above lucid commentary suggests....unless your turntable is as close to 'perfect' as possible in its speed consistency.....you are listening to 'distortion' without even realising it? |
Peterayer,
The better performance with this video is probably due to the fact that I now keep the TT=101 'powered up' permanently whereas previously......the turntable's circuits were 'cold'?
The results would probably improve even further after a few hours of actual use as I made the video from a 'first play'. |
Ketchup, I'll take you up on your offer. How do I get my email to you so that you can PM me? Thanks. |
Richardkrebs,
The music this time is Hymne a Saint Wenceslas circa 1237 from the album Rene Clemencic et ses flutes on Harmonia Mundi.
I agree with you...it is rather charming and the sonics are superb as with most Harmonia recordings. |
Is anyone else wondering what their highly accurate test procedure is? Yes....good point. Just more unsubstantiated Marketing Copy..... This is one of the reasons I fear the 'use' of the Timeline by manufacturers...? I simply don't trust them... Videos posted by manufactures displaying 'superb' Timeline results could be 'fabricated'? We really need actual owners of the turntables to post their results onto this Database....but that's easier said than done? Anyone who invests heavily in a well-known brand (especially an expensive one).....may not wish to publicise a poor result?....or may not even want to face the reality themselves? I fear those may be the reasons we don't have the NVS, the TechDas or the Caliburn submitted as yet? We certainly know that certain readers of A'gon do own these decks? |
Don, While I agree with others that correct instantaneous speed is an important measure of tt performance, it is certainly not the only thing to consider. Different tt's sound different, and it isn't always only due to differences in speed constancy. Yet somehow, I've gravitated to direct-drive and idler-drive (Lenco only); I hear my particular tt's as superior to the belt-drive tt's that I have owned in areas that probably really are related to their capacity to maintain constant speed despite countering forces that exist during LP play, but I've never owned a megabuck belt-drive tt that I might like better. Thus, from my experience, I feel unqualified to generalize. My subjective judgement of what I own and can afford is all that counts, to me. In the end, we're all in that boat. So, I sympathize in part with your view, but the obsession with speed constancy is not just hype. |
Halcro
Your choice of speakers are very suspect!
You hear "lucidity"? LOL!
I can not argue with religious theory.
There are many, many things that screw up Lp playback.
It never will be perfect! |
Halcro You have mistakenly attributed the following quote to Richardkrebs. 01-09-14: Halcro
Richardkrebs is right.....
Why is speed so important? As you know, the primary job of any record player, including turntable, arm, and cartridge, is to accurately reproduce the waveform of the music as it was originally recorded onto a vinyl record.... This quote has been lifted from the pages of IAR Magazine compiled by J Peter Moncrieff - Article on the Rockport Sirius III turntable. I note the article is subject to copywrite. Following convention it would be appropriate to acknowledge the correct author. |
Don
I don't think that any of us are claiming perfection. Well maybe one of us is. But we are, most of us, on an impossible quest for same.
Religious? Maybe a substitute, but it is a whole lot of fun.
Given the manyfold problems of vinyl playback, it is a miracle that anything resembling music is possible at all. So maybe a Devine presence is at work. |
I graduated from college and started working in Aerospace Engineering just as the WWII generation was starting to retire. I had the privilege of being mentored by engineers that started working just before and after WWII. This is the generation that designed and developed moon rockets, supersonic jet fighters, television and hifi. They did it all using slide rules and look up tables. It was an age of soulful design. On paper, vinyl playback looks bad. On paper, vacuum tubes look bad; but separately and even better together they make music magic. There is a lot to be said for Computer Aided Design and increased engineering productivity; but there is something about the Art of Engineering in vinyl records and the whole recording chain of the past, something remarkable that still amazes us in the 21st Century. |
Tony, words of wisdom. I have always thought that it´s a miracle that the vinyl groove and the magnetic tape are the recorded music itself. The triumphant victory of post war technology indeed. The modern digital tries to make playback perfect but it´s just an illusion, it still has a very long road ahead to perfection... Meanwhile we can enjoy the music and forget the modern digital technology.
But we can always try to make the analog playback even better and that´s the fun of it ! Here in AudiogoN universe many great minds are searching for the boundaries of the Analog but I wonder if there is anyone who has found them ?
Btw, my very heavy yet very humble TT usually maintains constant speed but sometimes doesn´t... probably due to fluctuations of mains AC. So it won´t pass the TimeLine test. That doesn´t worry me though as I have a very enjoyable system. |
01-07-14: Halcro
Peterayer,
I wasn't including you amongst those who have said that a very high-mass platter on a string or thread-drive turntable would be immune to stylus drag as you have admitted the fact......
Dertonearm and Dover I believe in the past (amongst many others previous to the advent of the Timeline)....have made such claims. Halcro, I have not made the claim that a high mass platter is immune to stylus drag. No turntable is immune to stylus drag. The unanswered question is how well do various turntables respond to stylus drag. Proposed Test Procedure In terms of Richardkrebs suggested testing procedure stylus off and on: this is not is not a valid test. What we are wanting to quantify is the variation in stylus drag between a heavily modulated record groove and lightly modulated record groove. The test that Richardkrebs proposes compares no stylus drag to some undefined recording. This is unscientific as it lacks a control recording to standardise the test. The results will be random and the conclusions meaningless. An accurate test procedure would be to agree on a specific record and tracks to be played. The record should contain a variety of tracks in terms of modulation. Then each person should play those tracks continuously from beginning to end. The sum total of the error at the end of this test will be truly comparable between turntables. As Tonywinsc suggested a meaningful sample would be 10 minutes, by which time any stylus drag error if it is significant would become apparent. 01-07-14: Halcro
Yet I have shown on my video of the Raven AC-2....the comparison when the stylus is NOT in the groove and I think that that gives a further comparison to both the motor, belt/string/thread and platter abilities of a belt-drive turntable......or ANY type of turntable.
Your comments (and Syntax's) about only being concerned by the performance when the stylus is tracking the record....is misleading.
I have recordings that have extremely modulated grooves and I have records which have very benignly modulated grooves.
I can adjust the motor controller to handle one or the other.....but unless the speed is manipulated for each and every record you play.......there will inevitable be a difference in the Timeline between different recordings.
This is why seeing the Timeline 'without load' in comparison to 'under load' is valuable. . You make the claim that unless the speed is adjusted for each and every record you play.. there will inevitably be a difference in the Timeline between different recordings.. From your comments above this is only true of the Raven AC2. It is wrong to assume that all turntables behave the same as the Raven AC2. For example, do you find that you also have to adjust the speed on your Victor 101 for each record. |
Tonywinsc, Hey, me too! It's also interesting how far you can go with plain old digital, regardless of what the digital designers have in mind. Lol |
03-06-12: Dover
Doesn't this discussion on DD servos highlight the question, does a very high mass platter, with very high inertia, driven by a high torque motor with a belt, thread or fluid drive with built in slippage, such that the platter mass will drive through any load fluctuations sound better than a DD with its constant speed correction. Dover, Perhaps your memory is fading? |
You have mistakenly attributed the following quote to Richardkrebs.
No,,,,,I was responding to Richardkrebs answer to Don_c55 about smearing of the soundwave due to speed fluctuations. If you...or anyone else thought that quote was attributed to Richard....my apologies. I communicated directly with Peter Moncrieff and obtained his permission in writing prior to posting his entire article on these Forums nearly 3 years ago. Perhaps you even read them here at that time? |
Dover, You seem to be full of suggestions for how people should submit their tests....yet you have not posted a single video of your 'famous' Final Parthenon performing with the Timeline in any fashion whatsoever? Up till now....my videos and that of the Fat Bob turntable used in the Timeline promotion on YouTube....are the only ones to my knowledge which demonstrate the reaction of the Timeline with the cartridge both playing the record and being dropped and/or lifted from the record. In both cases with a BELT-DRIVE turntable (as I have emphasised several times in this Thread).....there is a retardation of the Timeline dash due to 'stylus drag'. There are many on this Forum who claim that a BELT-DRIVE turntable with a high-mass platter and well regulated motor....will not be subjected to 'stylus drag'.
I am still skeptical about this....and we have seen no evidence with the Timeline that this is possible?
Hopefully someone will demonstrate such a phenomena? Did you miss the reference to 'belt-drive' again Dover? Until you start providing the visual evidence of your many claims.....I would suggest a modicum of restraint in your 'rules and regulations'? |
In agreement with Dover: Not only would one have to adjust the controller for each LP, but one would also have to leap out of one's seat to adjust the controller during highly modulated groove passages and then again when the music has smoothed out. I saw this very phenomenon whilst observing the Timeline on my friend's highly inaccurate belt drive tt (in fairness, later shown to have a malfunctioning motor controller). He had to run up to adjust the controller about every 30 seconds, in an attempt to quell the travel of the laser dot in one direction and then the other, across his listening room.
In disagreement with Dover: It was very unfair of you to indirectly accuse Richard Krebs of plagiarizing Moncrief (who is a scoundrel himself but in other ways). What Moncrief wrote, and what RK wrote, about tt speed as a determinant of musical accuracy, is self-evident to anyone who thinks about it. And RK did not claim to be the first to frame this obvious point. One may as well say that claiming the sun will rise in the morning is stealing from Copernicus (one of Halcro's favorite people).
Further, it's "copyright", not "copywrite". |
Ketchup, I'll take you up on your offer. How do I get my email to you so that you can PM me? Thanks. The only way to contact someone through Audiogon that I know of is to click "Learn" then "Member Directory." Look up the person you want to contact and then click "Send Message." I'll send you a message now. |
01-10-14: Lewm
It was very unfair of you to indirectly accuse Richard Krebs of plagiarizing Moncrief Lewm, if you read my post correctly I said Halcro
You have mistakenly attributed the following quote to Richardkrebs. We may have a different interpretation of the english language, but I do not equate "mistakenly attributed" to mean "plagiarised". Do you not agree that one should acknowledge the correct source if one lifts several paragraphs directly from an article written by someone else - word for word ? |
Halcro 01-10-14: Halcro
Dover,
You seem to be full of suggestions for how people should submit their tests....yet you have not posted a single video of your 'famous' Final Parthenon performing with the Timeline in any fashion whatsoever?
Up till now....my videos and that of the Fat Bob turntable used in the Timeline promotion on YouTube....are the only ones to my knowledge which demonstrate the reaction of the Timeline with the cartridge both playing the record and being dropped and/or lifted from the record. Halcro - Did you miss the knuckle test I posted. knuckletest Regard the suggestions - the methodology of your Timeline test is flawed. My proposal is for a more accurate and meaningful test that would provide consistant parameters under which all turntables can be evaluated. 01-10-14: Dover
Proposed Test Procedure
In terms of Richardkrebs suggested testing procedure stylus off and on: this is not is not a valid test. What we are wanting to quantify is the variation in stylus drag between a heavily modulated record groove and lightly modulated record groove. The test that Richardkrebs proposes compares no stylus drag to some undefined recording. This is unscientific as it lacks a control recording to standardise the test. The results will be random and the conclusions meaningless.
An accurate test procedure would be to agree on a specific record and tracks to be played. The record should contain a variety of tracks in terms of modulation. Then each person should play those tracks continuously from beginning to end. The sum total of the error at the end of this test will be truly comparable between turntables. As Tonywinsc suggested a meaningful sample would be 10 minutes, by which time any stylus drag error if it is significant would become apparent. |
While I agree that it would be best for every test to use the same LP, this is likely an unrealistic requirement since it presupposes that every tester has this disc.
Futher " The sum total of the error at the end of the test would be truely comparable between turntables"
This would not necessarily be an informative result.
Say a TT that isn't speed stable, which has adjustment is set for correct speed at moderate groove modulation. When playing heavy grooves it may under speed when playing light grooves it may over speed. The average speed over the test could be correct with the laser back on its starting point at the end, apparently passing the test.
The no load followed by some, ideally standard, heavy grooves is an arduous test. If it passes this it is likely that it would pass real world playback.
This provided the laser is observed under no load conditions and this is the control, (TT adjusted if possible, necessary, to zero drift)
Also if a TT passes this test it would be reasonable to assume that it would be ok with light grooves.
But, as I implied with the Goldmund comments, we are not seeing how the TT performs at a note by note level. |
The no load followed by some, ideally standard, heavy grooves is an arduous test. If it passes this it is likely that it would pass real world playback. I agree..... I thought this would be obvious to anyone familiar with the principles involved? |
Halcro, I agree the test record has an eccentric hole, as do most music records, so the variation in speed from the effects of warps or eccentricity is there on all records to some degree, do you think this makes a mockery of perfect rotational speed? Perhaps Nakamichi was onto something with their record centring mechanism. I have posted screen shots of the Feickert test on the TS 700 with and without centring, and it makes a considerable difference! I suspect the variations detected by the test tone +- 2 Hz at 3150Hz, would be undetectable with the time line. Did Nakamichi make the "best" TT of all time?:) |
Dover, My apologies. I probably sounded more indignant than I actually am or was. Perhaps lifting the paragraphs word for word (I knew they sounded familiar) with no attribution is not.... something. But this is the internet, all junk food all the time. |
Dover, yet you have not posted a single video of your 'famous' Final Parthenon performing with the Timeline in any fashion whatsoever? You really need to work on your comprehension skills. Your 'speed reading' abilities are flawed..... Again you ignore the vital word....TIMELINE....? Halcro - Did you miss the knuckle test I posted. No...I got that one. It's about as useful as demonstrating a turntable being able to perform under water? It demonstrates a serious lack of appreciation for the actual forces involved on the stylus due to groove modulation and friction which are responsible for 'stylus drag'. But FYI....the TT-101 passes this nebulous knuckletest.....not for the three paltry seconds on your video....but for the full 3 minutes with the TIMELINE....not the inaccurate strobe which you continue to use. |
Dinster,
I have a good friend who owned a mint Nakamichi TX-1000 among his EMT927, Micro SX-5000 and SX-8000 as well as Continuum Criterion collection.
After a year or two....he became disillusioned with the sound of the TX-1000 in comparison to his other decks and sold it.
Centring the hole of the Lp does not guarantee consistent speed control of a particular turntable?
It simply removes one possible cause of distortion when playing an eccentric record on a turntable WITH perfect speed consistency..... |
Lewm, thanks for your kind words. I agree there is a lot of "junk food" on the net. |
Halcro, It would be very interesting to see a TimeLine test video of a very eccentric record´s play with 3 tonearms in action. |
I would like someone with the TimeLine to make very small incremental adjustments in speed similar to the speed changes due to stylus drag.
Then listen closely at these different speeds, on records that have light and heavy modulation, and try to hear changes in sonics.
I do not think these changes (during play) are audible, as J. Peter Moncrief's theory (which Halcro quotes), implies.
He was "the" supreme theoretical BS artist, in his day. |
Don, Then listen closely at these different speeds, on records that have light and heavy modulation, and try to hear changes in sonics. I think you're talking here about speed 'consistency' rather than 'absolute' speed? I have no doubts that you are correct in the fact that if a turntable is running CONSISTENTLY fast or slow....and can cope with 'stylus drag'....the resulting sound will be undistorted and one could not really tell the difference. In fact...the TT-101 has the facility to adjust the speed either UP or DOWN in 4 Hz increments so that one can match the relative 'pitch' of the record with an instrument that one might wish to play along with. The only problem here....is that we don't have a Timeline which can alter 'pitch'....so that consistent speed of a turntable under stylus drag can only be verified by the Timeline at exactly 33.33rpm. |
Not to beat a dead horse, but if one were to measure precisely the left or right movement of the laser spot over time with no stylus drag and then do the same thing in the presence of stylus drag, one could in fact establish that the tt is capable of maintaining some constant speed in spite of stylus drag, even if that speed was greater or less than 33.33 rpm. |
Lewm,
After reading this thread for weeks now, this is exactly my question, and what I have not seen addressed in any of the posts so far. If it has been addressed, my apologies.
If a turntable slows down for a very brief moment due to the stylus drag and the Timeline registers it by shifting the laser spot but then remains constant, how relevant is that drag save for the very brief moment of the stylus settling in the grooves and the turntable adjusting its speed? |
I think the confusion lies in trying to use the Timeline, which shows average speed over any period of time, to evaluate momentary, micro-variations in speed due to stylus drag. The timeline can only infer that speed is varying once the stylus is in the groove if the laser mark drifts. The problem is you can't know if the drift is due to speed being something other than 33 1/3 exactly or if speed is actually changing during play. The only sure way to measure the effects of stylus drag on speed for a particular tt is with a very fine tachometer.
Think of driving your car. You time yourself from point A to B and knowing the distance determine your speed. That is average speed. If you want your speed to be exactly 30 mph then you must leave and arrive within a specific time interval. The thing is, you don't know what your speed variation is between points A and B. In order to know your speed variation you must watch your speedometer. The speedometer is giving you instantaneous speed. Showing your stopwatch to someone as proof that you drove exactly 30 mph between A and B doesn't prove that your speed was a constant 30 mph. Maybe you went up a hill and dropped to 25 and then down a hill and got up to 35 for a moment averaging out to 30.
The timeline is like a stopwatch giving you average speed. |
Lew,
If you watch my video of the Raven AC-2 with the Timeline.....you can see exactly what you suggest albeit in reverse.
You can witness the Timeline laser moving incrementally to the left as the record is playing.....whilst when the tonearm is lifted.....the laser is stationary.
This means that the turntable is spinning exactly at 33.33rpm without stylus drag....but runs slightly slower WITH stylus drag. |
