Rockport came the closest with its Sirius III Hi Halco, just wonder whether you have any measurement figures on the Rockport Sirius III, with Timeline or otherwise. I am really interested to see how the Sirius III compares to vintage Japanese DD turntables. Thanks! |
Halcro, I told you where I read that stuff and asked if it was correct. You don't seem too sure about all the additional complexity you talked about. It's all from the speed control adjustments and breaking?
As far as platter weight you said, "This is a subjective view and IMO has become an oft-repeated audio myth... It implies that turntables like Rega and Project cannot have "solidity"to their sound.... I have found that to be too much of a generalisation."
You're arguing against an implied generalization? First of all I never made that generalization. Secondly, I still believe that "audio myth" has some merit. You make a good case for speed stability and I'm not disputing that, but it's not the only parameter IMO.
Now I'm playing devil's advocate against vintage tables? Of all the millions of DD tables sold back in the day, I wonder how many have burned out motors or discarded for a broken part or lack of a good tech. All I own are vintage tables, but for some people new is easier, especially with dealer support. Maybe VPI has gone rogue, but most companies support past product. |
Hi Thekong, I don't know how many Sirius IIIs were made nor how many are still in operation......but it was more than 10 years ago that I was able to listen at length to one in my friend Richard's system. That was before the Timeline or the Feickert Speed App...👀 What I remember clearly to this day, is the shock of hearing familiar records reproduced with a clarity, brilliance and definition from the mids to the ultra-highs I was unused to. The lack of mid-bass to lower-bass definition and power I wrongly or rightly lay at the feet of the tangential tracking arm...... With my Victors....especially since the granite cradle....that clarity, brilliance and definition are now familiar residents chez moi 😋 albeit without the forward emphasis of the Rockport (probably due to the balance of the complete bass presentation with the Victors)...? Richard has had a Caliburn for the last nine years so opportunities to test the Sirius III have deserted me. It would indeed be interesting to see how she tests against the best vintage Japanese gear..? Regards |
Fleib,
I do hope what ever is wrong with your UA-7045 is something that can be easily fixed. That is the tone arm I currently have mounted on my TT-81. You will be quite impressed with it if becomes fully operational. In regards to the arm board on my Aries. It currently has the Graham arm board which I bought from Bob Graham to use with his 2.2 arm. I do have the original arm board that came with the Aries. It has been drilled for the Graham but I have not checked it to see if I could possible re-drill it to make it usable for the Lustre. In all honesty, I have never had any problem with getting anything from VPI before. But they did sell a lot of these so I suspect they just sold all their back stock. I was quite surprised at their reply. It is after all nothing but a acrylic hockey puck! Bob Graham has done the same thing with his arm wands for the 1.5, 2.0 and the 2.2. Due to certain production parts being unobtainable, you can not buy additional arm wands. He will do limited repair based upon parts available. This arm is not that old! I know our world has become a throw-away society, but come on! Regards, |
Fleib, Just a thought I had...... How does the cartridge know the mass of the platter....❓👀 Regards |
Hi Halco,
I was also blown away the first time I auditioned the Sirius III at the dealer over 10 years ago! However, I didn't notice any lack of mid-bass to lower-bass definition and power, maybe due to the different setup. Not sure about the air-supply in the Sirius III, but the stock air-supply for my Rockport 6000 arm is certainly inadequate, and major improvement can be had with a Jun Air compressor with integral surge tanks and multilevel of air regulations. With this upgrade, I don't feel the tangential arm is lacking in bass definition and power. If pressed, I may admit that the bass quantity maybe so very slightly less than arms like the FR64S, but the soundstage depth and width is something to die for.
But then, I must agree the performance of these flagship vintage DD turntables are shocking. It would be interesting if a direct comparison with the Sirius III could be arranged!
I have just managed to get hold of a Technics SP10MK3 from Japan, so will have some fun setting it up in coming weeks!
Cheers |
You're a lucky man Thekong... Did you actually own the Sirius III or did you just have the arm? If only the arm...what table did you have it on? Will be most interesting to hear your impressions once you have the SP10-III bedded in...😋 |
I wish I have a Sirius III, but no such luck yet! My Rockport 6000 arm is a simplified version of the Sirius III arm, and it is on a Capella II TT.
However, I am also in the process of setting up a Sirius II, so it would be interesting nevertheless to compare it to the SP10MK3 and Exclusive P3A in coming months :-) |
You didn't buy the SP10/3 and P3a that were just listed on HiFiDo....did you Thekong..? |
No, the P3a was from a friend in Hong Kong, and the SP10MK3 from Yahoo Japan. Actually, a local Sony PS X9 slipped through my fingers just a couple on months ago! |
Griff, I don't usually speak against VPI, but their answer to your inquiry, "I was told by a return email that they no longer provide arm boards for the Aries", doesn't seem open to future possibilities. Perhaps their answer was worded differently, or that's not exactly what they meant?
If some part or material has become unobtainable, there's not much they can do, but VPI now seems to have a take the money and run philosophy. They sell out their parts for discontinued tables (HW19, TNT, Traveler) and abandon their product and customer. You could take the first Sota ever made, send it to Sota for refurb and they'll give you options. It would probably make more sense to buy a new table, but they don't leave the customer hanging. Rant over.
I can fix everything on the 7045, except I'm not sure about the VTA adjuster lock. It seems frozen in the open position. Does the arm need to be mounted for it to lock? Not too late to cancel the charge. BTW, I was surprised to see the counterweight fixing bolt is 4mm thread. Heavy duty arm. Regards,
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Henry, "How does the cartridge know the mass of the platter....❓👀"
You mean "know" in the biblical sense? When cart suspension collapses?
I think you would agree that platter and mat, supporting surface, does make a difference. Some platters are designed to use w/o mat and your experimentation with mats indicates agreement. IMO, these things can not be considered in isolation. Consider an extremely lightweight platter, would tend to be more easily affected by extraneous vibrations despite stability of supporting structure. What about sound pressure waves? Maximum thickness of a mat is 5-7mm? Just enough to turn the shortcomings of a light platter, to mush.
Before you get reactionary, I'm not saying your Victors have extremely light platters, but platter mass can make a difference IMO. Consider the older Goldmund Reference - servo belt drive w/35lb platter. TT101 might have better pitch stability, but better sound is a matter of opinion. I wonder what you'd think of a Reference with one of your arms mounted. Regards, |
Fleib,
When you say VTF adjuster 'lock' are you referring to the locking nut that allows the shaft to freely move up and down? There is a nut that attaches the arm to the arm board. Then there is a nut that unlocks the arm shaft that would allows the shaft to freely move up and down when opened. When you 'unlock' it, hold on to the arm because it will freely fall and bottom out. You use that one to get the working end of the cartridge into the 'general' VTA area. Once both of those nuts are locked into place, then you can use the 'numbered' VTA adjuster +/- thumb wheel device to fine tune VTA. To do the initial set up, I set the +/- thumb wheel in the center of its +/- range. There are arrows to define this position. Then loosen the locking nut while holding onto the arm so it doesn't drop down freely, then roughly position the arm where I think it should go, lock the nut, the do the final VTA settings. Once you have done this a couple of times, you kind of get the feel for where the shaft should be located when you lock the nut. If it was set (locked), with the arm too low, you will be forced to use only one end of the +/- scale. Too high, you will be forced to use the other end of the scale. I shoot for a general 'center' position of the +/- scale. I shoot for that position mainly because of all the different height cartridges that I have. Regards, Don |
Halcro. In the manual of the ET2 Bruce Thigpen claims that a pivoted arm contributes to wow and flutter due to its geometry.
The TT-101 has exceptional figures in this area. Since you have a rig with 3 arms, it would be interesting to run 3 consecutive tests of say 1 minute each with the three arms. This to to see if there is any difference. Each arm has different geometry, so if Bruce is correct, we may expect to see a difference between the three readings.
Purely for academic interest. |
Technics SP10 Mk3No affiliation with listing party but thought you guys would be interested Good Listening Peter |
If anyone was interested in an SP10 Mk3, this one may be better value as it includes tonearm and base... |
Halcro.
I re-read my last post and realise that it could be misinterpreted. Clarification here...
BT suggests that when accessing speed accuracy with a pivoted arm, the measured performance is inferior to the actual performance. This due to the geometry of a pivoted arm.
Since you have a rig with three different arms, it would be of interest to run three sequential tests to see if there are any measured differences. If there are, maybe we could infer that the TT-101 is actually better than the readings indicate.
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Richardkrebs, The measured performance is inferior to actual performance?
Wow and flutter can only be measured with an arm/cart. Timeline measures or illustrates absolute speed. Henry has shown that absolute speed doesn't deviate when using 3 arms simultaneously on his Victor.
W/F is measured with a test record 3150Hz tone. Output is checked for deviation from that frequency. I think Thigpen must be referring to low torque belt drives, in which case a gnat landing on the arm or platter might upset speed stability. Regards, |
10-23-15: Fleib Richardkrebs, The measured performance is inferior to actual performance? Wow and flutter can only be measured with an arm/cart. Timeline measures or illustrates absolute speed. Henry has shown that absolute speed doesn't deviate when using 3 arms simultaneously on his Victor. 1. There is no such thing as absolute speed. Speed is relative. 2. Wow or flutter can be measured with a rotary function generator connected directly to the platter - this is the method Thigpen uses. 3. Using a record with a fixed tone is prone to error. Any eccentricity or imprecision in the surface of the record will generate wow or flutter. 4.The timeline only measures the arrival of a single point on the platter at the same place at each time. It does not measure what happens in between. If you take points 2 and 3 above into account, then when playing records there will be more wow and flutter generated by the arm/cartridge than the TT itself. If you want to relate Direct Drive speed stability to sound quality consider this: Analogue wow and flutter is similar to digital jitter. Testing of digital systems as regards temporal errors and the effect on sound quality has yielded the following - 1. The lowest level of jitter that affects sound quality is 5 nanoseconds. 2. Using sine waves for testing showed most people could hear errors down to 10 nanoseconds. 3. On recorded music people could here down to 20 nanoseconds. I have seen some studies that suggest temporal recognition in the brain is triggered at around 4 nanoseconds. There is no way that the error correction circuitry from these vintage decks is fast enough to be inaudible. If the listener thinks that their TT "sounds" more speed stable than anything they have heard before, then their perception of their current turntable on its relative merits is limited to a relativity to the inferior tables that they have previously used in that particular system. |
Dover, "There is no such thing as absolute speed. Speed is relative."
That is incorrect. For a turntable, 33 1/3, 45 RPM is absolutely the correct speed. How it's measured is another story.
"The timeline only measures the arrival of a single point on the platter at the same place at each time. It does not measure what happens in between."
That was my point, commonly referred to as absolute speed vs. wow and flutter.
"Analogue wow and flutter is similar to digital jitter. Testing of digital systems as regards temporal errors and the effect on sound quality has yielded the following -"
Analog wow and flutter is very different from digital jitter. Your analogy is a bad one. Because of the continuous nature of analog, very small amounts of W/F are much less noticeable. Not so with digital. Because the music is chopped up and regurgitated back to analog, any jitter is more prominent, noticeable. This is especially true with harmonics and tonality.
Playing records is harder, more expensive, and a PIA compared to digital. Then why the resurgence, because it's cool? I don't think so. It's more fun because it sounds better. Regards, |
Fleib, Speed is never absolute. It is always measured from a point of reference. The planet is rotating, the measured speed on your platter is relative to the rotation of the planet - it cannot be absolute.
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Fleib. Copied here the reference to wow and flutter from the ET2 Dampening trough owners manual.
Food for thought.
"WOW AND FLUTTER Wow and flutter, FM distortion and surface irregularities in the LP should all be grouped together because, as we will see, they are all tied together. When you cut a pure tone (say 1kHz) onto an LP and then play it back on a turntable/tonearm/cartridge system, you would hopefully want 1kHz to come back. Something close to 1kHz comes back, but rapidly being shifted up and down around 1kHz. If the frequency is shifted up to 1001Hz and down to 999Hz within a short period of time, the amount of shift is .1%. If the shift occurs less than 10 times a second, it is considered as flutter. The two measures are generally lumped together and called wow and flutter. “Weighting” is applied to the measurement to reduce the measurement’s sensitivity to very low and very high rate of frequency shift. The actual amount of frequency shift is much greater than the number implies. The weighting network is supposed to create a number related to a subjective ability to hear wow and flutter. Reviewers have incorrectly attributed wow and flutter to the turntable. Since the advent of the belt drive turntable, wow and flutter has been purely a function of tonearm geometry, the phono cartridge compliance with the elastomeric damping, and surface irregularities in the LP. In our own lab we have measured many high quality turntables using a rotary function generator directly connected to the platters of the turntables. The measured results are usually an order of magnitude better than the results using a tonearm and test record (conventional wow and flutter method). Further proof exists if you take two tonearms, one straight line and one pivoted and mount them both on the same turntable. The straight line tonearm will give a wow and flutter reading with the same cartridge/test record of about 2/3 to ½ that of the pivoted arm (.03% < .07% to .05%). This is because the straight line tonearm has a geometry advantage and lateral motion does not result in stylus longitudinal motion along the groove of the record. Another proof is to take two different cartridges, one high compliance and one low compliance, and take measurements with both using the same turntable and tonearm. The reading of wow and flutter will be different. All wow and flutter readings are higher than the rotational consistency of the turntable A damping track applied to a tonearm (straight line or pivoted), will reduce the measured wow and flutter usually 10-30% and sometimes as much as 50%. ET-2 wow and flutter readings with a typical cartridge and good turntable will usually measure (.02 to .04%) which is extremely low for an LP system. With the damping track installed flutter readings with the ET drop still lower and with one test record we measured readings as low as .007%. Surface irregularities on the vinyl of the LP record are the primary cause of rumble or random low frequency noise, which causes the tonearm/cartridge spring system to start oscillating. This oscillation occurs continuously during playback. It is a primary cause of wow and flutter and FM distortion in phono playback. Surface irregularities occur not as a part of the record cutting process, but result from the molding process used in making the record You can see visually small ripples on the surface of an LP as it is turning. These continuously excite the tonearm resonance" |
RK, Just as I thought. Thigpen says, "Since the advent of the belt drive turntable, wow and flutter has been purely a function of tonearm geometry, the phono cartridge compliance with the elastomeric damping, and surface irregularities in the LP."
He's measuring tables with no load (absolute speed) and comparing to W/F measurements with cantilever oscillation thrown in. Yes, the belt drive tables are often more susceptible to external forces presented by a pivoting arm. This is not to say DD/idlers are immune, but I think we've all heard what happens with low torque tables of any type, when the needle drops.
This sales pitch is misleading because he takes TT speed stability out of the picture and replaces it with arm geometry, although benefits might be true for those with low torque tables. I haven't considered W/F as a function of arm damping, but I don't like low torque tables. The term oscillation implies an increase in magnitude, but that's interpretive. Regards,
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Thanks for that interesting excerpt Richardkrebs. I wish he had included the graphs, charts and figures to properly support his claims.... We of course are now able to graphically demonstrate some actual performance charts and figures for various turntables under test. Dover still resorts to imagined 'monsters' from his antipodal 'sleep of reason' as witnessed by 4.The timeline only measures the arrival of a single point on the platter at the same place at each time. It does not measure what happens in between.
He strangely ignores the Feikert Frequency Response Charts posted which demonstrate a 'real-time' ANALOGUE print-out over a 30 second time interval....an interval comprising 16 revolutions of the platter....which disproves his (and your) theory of malevolent speed behaviour BETWEEN the Timeline recording interval. It is indeed revealing that Dover has never had the intestinal fortitude to post his Final Parthenon turntable performances under both the Timeline and the Feikert Speed App yet continues to boast of its abilities. I am dubious in the extreme.....😎 As for your idea of testing the various arm/cartridge combinations on my TT-101...I don't believe the Feikert Speed App is accurate enough for this contest. In fact....if you conduct three 30 second test measurements with the identical table/arm/cartridge (without touching the set-up)...you will receive three sightly different results. But as far as we can visually disprove Thigpen's theories, here are the Frequency Charts for my three arms and cartridges. WE8000/STFR-64S507/IIAnd just to show that not all DD turntables are the same here is the Onkyo CP-1050I have seen some good performance charts for some belt-drive decks....but just to show you what some are capable of.... Wilson BeneschGeorge Warren |
Halcro.
Thanks for the tests. Do you have the companion numbers for each arm? I was interested in any consistent differences between the arms/carts, which could go some way to validating BT's ideas. There was nothing else in my request.
As for Dover's and my comments about what is happening "between" each pulse of the time line. I was hoping that this topic was in the 'agree to differ basket', but since it has been raised....you only need look at the traces you have just posted. Sharp spikes on the raw trace... this is a servo in action! Rapid acceleration/deceleration of the platter. Yet the platters average speed is 33 1/3. The smoothed ( green) trace filters these spikes, so it tells only part of the story. cheers. |
Sharp spikes on the raw trace...this is the servo in action. Hmm....both belt-drive turntables must also have servos....if that's what sharp spikes indicate......🙈 |
Halcro The Wilson does have speed feedback, don't know about the George. If you look at the George's raw trace, even though it is all over the place, it is quite smooth in comparison to the others and approximates a sine wave. This would imply a different speed control architecture.
The key point is that that the traces you posted clearly show that within a single revolution, the TT-101 has significant very short duration speed changes, but it's AVERAGE over one revolution is exceptionally stable.
Cheers. |
Halcro - 10-23-15: Halcro ..Dover still resorts to imagined 'monsters' from his antipodal 'sleep of reason' as witnessed by 4.The timeline only measures the arrival of a single point on the platter at the same place at each time. It does not measure what happens in between. He strangely ignores the Feikert Frequency Response Charts posted which demonstrate a 'real-time' ANALOGUE print-out over a 30 second time interval....an interval comprising 16 revolutions of the platter....which disproves his (and your) theory of malevolent speed behaviour BETWEEN the Timeline recording interval. That is not correct - point 2 in my post you refer to highlights that the Feickert test record can be prone to error - evidenced by the fact that the weighted averaging process is supposed to account for eccentricities in the record ( see Feickert for confirmation ). 10-23-15: Halcro As for your idea of testing the various arm/cartridge combinations on my TT-101...I don't believe the Feikert Speed App is accurate enough for this contest. In fact....if you conduct three 30 second test measurements with the identical table/arm/cartridge (without touching the set-up)...you will receive three sightly different results. Indeed, you have confirmed that the Feickert is not accurate enough to quantify the micro changes in speed between the test intervals. I would also remind you that in your earlier testing you indicated that you got different results if you rotated the record a quarter turn. 10-24-15: Richardkrebs As for Dover's and my comments about what is happening "between" each pulse of the time line. I was hoping that this topic was in the 'agree to differ basket', but since it has been raised....you only need look at the traces you have just posted. Sharp spikes on the raw trace... this is a servo in action! Rapid acceleration/deceleration of the platter. Yet the platters average speed is 33 1/3. The smoothed ( green) trace filters these spikes, so it tells only part of the story. In Fremers testing thus far he highlights the vastly different shapes of the raw trace between the Caliburn and the Onedof even though they measure similarly, indicating differences in micro timing vs macro timing. I would also expect for example differences in the shape of the traces according to motor type - AC motors tend to self correct sinusoidally, whereas DC motors tend to correct trapezoidally. An important point is that we can only do true comparisons where the testing instruments, protocols, and environment are constant. In other words comparing your results to Fremers is not scientifically valid. There will be differences in the test records, there are errors integral in the iPhone/computer apps that vary depending on model, and many other variables. |
the TT-101 has significant very short duration speed changes, No.....the Wilson Benesch has "significant very short duration speed changes"and the George Warren has "significant very short duration speed changes" and the VPI Direct has "significant very short duration speed changes" and the Continuum Caliburn has "significant very short duration speed changes'. The TT-101 has less speed change than any turntable so far shown. If you can show results for any turntable with LESS speed changes than that of the TT-101.....please do so. |
Halcro Look at the raw trace for the WE8000. Start at the first lower min freq, just above 3130 hz. Other than the max at around 3164hz, count every sharp change in direction until immediately before the next min of around 3130 hz again. I count 14. The platter changes speed 14 times during that single revolution.
Cheers. |
Dover, All you and Richardkrebs do is disparage every scientific test method we have available for turntables without ever offering an alternative. If you have nothing to offer to help analyse a turntable's performance in an objective manner, perhaps you should both just ignore these discussions... |
So show me all the speed changes in this raw trace frequency chart Richardkrebs? |
Halcro.
The TT-101 is a machine, a thing, nothing more. It, like all machines, is far from perfection. My objective comments, made as a result of properly interrogating all of the Feikert test data you provided, are in no way a reflection on its owner. The same cannot be said for your attempt to censor me by suggesting I "ignore these discussions" because I posted facts that you find uncomfortable.
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Dover, "Speed is never absolute. It is always measured from a point of reference. The planet is rotating, the measured speed on your platter is relative to the rotation of the planet - it cannot be absolute."
We're talking rotational speed not land/air/sea speed. It's as absolute as the timing of a minute. Regards, |
RK, "Look at the raw trace for the WE8000. Start at the first lower min freq, just above 3130 hz. Other than the max at around 3164hz, count every sharp change in direction until immediately before the next min of around 3130 hz again. I count 14. The platter changes speed 14 times during that single revolution."
A tone is a vibration, a sine wave, not a straight line on a scope. You have to compare to a "pure" tone generated for 3150Hz. Regards, |
If Dover and Richard (and Fleib) were to refrain from commenting, we would all be the poorer for it, and this fun thread might be dead. Carry on, gentlemen. |
For those belt-drive turntable owners who are concerned at the 'servo-control' jagged spikes on their Feikert Frequency Chart, here is a what Marcus Ribi from Feikert Platterspeed has to say about the change in the software.... The approximate sine wave form of the chart is resulting from eccentricity of the record. A normal measurement of WOW and flutter with a perfectly centered record will NOT show such a wave form, but a more random spiky form instead. That's what the spikes are coming from: it's a superposition of eccentricity and "real" WOW and flutter. Measurement of WOW and flutter then tries to best filter away the regular changes comig from record eccentricity to provide best results. |
I wonder how accurate this is. The waveform peaks at +16Hz and bottoms at -20Hz. That's a spread of 36Hz, a little more than 1%. A scope or a meter with a frequency counter could be used to check results.
Another fly in the ointment - Werner Ogries EE, has reported calibration errors in both HFN and Analog Productions test records. Not sure of all the gory details. |
Taking a break from applied technology, how about remedial physics? What do MPH and RPM have in common? Time is a dimension we have divided precisely, based upon, but not dependent upon, the movement of Earth around the Sun. Our division of time does not exactly agree with the rotation of Earth and has to be corrected at regular intervals. It could be divided arbitrarily, but the days and seasons might not agree with nature.
The Earth rotates in a counterclockwise (west to east) direction at approx. 1040 MPH at the equator. If you went to Brazil near the equator and drove a car 100 MPH west, you'd actually be going backwards at 940 MPH and wind up in the Atlantic ocean?
Rotational speed of an object on Earth is not dependent on the rotation of the planet. Either is land speed. As long as we have precise and agreed upon divisions of time and distance, the rotation of Earth could cease and we would still be able to apply our divisions of time. We would still be able to play a football game, do the dishes and take a walk, weather permitting.
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Fleib.
The error resulting from record eccentricity is surprising.
Take a small 0.5mm eccentricity on a 100mm radius and we get around a 1% error. (The tracking radius makes a difference)
Nakamichi were on to something way back then. |
Halcro, thank you for taking the time to confirm that my original assertions on the disadvantage of using a test record to measure Wow and Flutter were correct. 10-23-15: Dover 3. Using a record with a fixed tone is prone to error. Any eccentricity or imprecision in the surface of the record will generate wow or flutter. As Marcus Ribi from Feickert says.. 10-26-15: Halcro .. Marcus Ribi from Feikert Platterspeed The approximate sine wave form of the chart is resulting from eccentricity of the record. A normal measurement of WOW and flutter with a perfectly centered record will NOT show such a wave form, but a more random spiky form instead. That's what the spikes are coming from: it's a superposition of eccentricity and "real" WOW and flutter. Measurement of WOW and flutter then tries to best filter away the regular changes comig from record eccentricity to provide best results. In the final analysis the key sentence in Feickerts response is "tries to best filter away the regular changes coming from record eccentricity to provide best results". The Feickert software uses algorithms to calculate and remove errors generated by eccentricity. These are an approximation at best. If you had a faulty turntable with a regular error with each rotation, the averaged WOW & Flutter reported could understate the true WOW and Flutter if the algorithm ascribes the resultant speed issue generated by the fault to eccentricity". |
10-26-15: Richardkrebs Fleib. The error resulting from record eccentricity is surprising. Take a small 0.5mm eccentricity on a 100mm radius and we get around a 1% error. (The tracking radius makes a difference) Nakamichi were on to something way back then. Assuming for arguments sake that this number is correct, then given that record spindle diameters can vary from 7.09 to 7.21 then we are looking at errors of 0.2% even before we take record eccentricity into account. Richard, given that most records are eccentric to some degree, could you explain why you have increased the horizontal mass of your ET2 by 300% adding lead to the spindle and removing the decoupled counterweight, when it is clear that increasing the horizontal mass will increase the wow and flutter on playback by a significant degree on eccentric records. The testing I did on my ET2 with removing the counterweight resulted in audible degradation of the sound. |
Dover.
Yes "removing the counterweight" would result in a dramatic degradation of the sound!
As to increasing the horizontal mass of my arm by 300%. One needs to specify at what horizontal frequency this measurement is taken. At 0.55Hz (eccentric record at 33 1/3 rpm) the leaf spring on the ET2 counterweight is stiff. IOW on a standard ET2, at a horizontal excitation of 0.55Hz, the mass of the counterweight assembly must be added to the weight of the spindle, wand and cartridge. This means that when tracing an off centre record, my cartridge sees more or less the same mass as one mounted on a standard ET2. (applies to average weight cartridges and associated counterweights) BT has confirmed this and I posted his response on the ET thread, maybe you missed this?
Resonance transmissibility theory 101
cheers. |
Richard - thank you for reminding me. Yes I see where I have gone wrong - I listen to music at full frequency range, including those above 0.55hz. |
10-24-15: Halcro Dover, All you and Richardkrebs do is disparage every scientific test method we have available for turntables without ever offering an alternative. Henry (Halcro) I used to have this boss; who upon first meeting you in his office would say... "Don't dare bring any problems to my attention without offering solutions." Now I have no boss. But my wife is trying her best to become one :^( *********************************************************** AudioGon Analog Forum ratings highest on Audiophile Saturday night in this part of the world, when Richard and Dover post in succession on a thread. There is this, how do I say it, intangible, hard to describe .........chemistry between them. |
Dover, As you've already pointed out.......since the availability of the Feikert Speed App I have regularly stated that the Data downloaded on its 'Chart Info' was imprecise and non-scientific as it was not possible to duplicate the results from test to test. On this point you and I are in agreement. The Frequency Chart on the other hand, is a more reliable visual snapshot of the absolute speed and actual speed variations over a 30 second timespan if you observe the Low-Pass Filtered Frequency. The Raw Frequency plot should be ignored as it is subject to the Feikert-designed software algorithms to enable the Low-Pass Filtered Frequency plot to be produced. The jagged lines are part of their software programming to compensate for record eccentricity and do not indicate, as Richardkrebs erroneously proclaimed....."significant speed changes caused by the servo control". IMO the low-pass filtered frequency plot is a viable tool for turntable performance comparisons as indicated by those I showed of the Wilson Benesch and George Warren. The real shock was the realisation that both these turntables were able to be listened to without much concern....😱 Analogue is so forgiving...🎧 |
Chris, There is this, how do I say it, intangible, hard to describe .........chemistry between them. 😎 Perhaps it's a Kiwi thing...❓ They may both settle down a bit next week when we beat them in the Rugby World Cup.....😜 |
Halcro.
The explanation from Marcus confirms my comments re the 14 speed changes in the first revolution.
Here is the relevant sentence...
"That's what the spikes are coming from: it's a superposition of eccentricity and "real" WOW and flutter."
The raw data tells us much about the nature of the platters rotation. We see the "real" WOW and flutter as distortion of the sine wave.
In other words, perfect speed would show just a sine wave symmetrically centred about the 3150hz line on the raw data graph. This then being filtered by their program to produce a straight line at 3150hz for the low pass graph.
cheers. |
Richardkrebs... In other words, perfect speed would show just a sine wave symmetrically centred about the 3150hz line on the raw data graph. Markus Ribi... A normal measurement of WOW and flutter with a perfectly centered record will NOT show such a wave form, but a more random spiky form instead. Richardkrebs... Sharp spikes on the raw trace... this is a servo in action! |
Halcro.
Perhaps you misinterpreted my last post. When I said "perfect speed" I did not mean "perfectly centered".
A real world test record, which is off centre, produces the sine wave. Speed errors are superimposed on this sine wave, as Markus says.
So with a real world test record running at perfect speed, we would get the results I described.
cheers.
Go the ABs! |