You are addressing the more interesting point - you adjust tension for the better sound or for the best figures?
Natural Sound
- Thread starter PeterA
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You are addressing the more interesting point - you adjust tension for the better sound or for the best figures?
Certainly, but maybe the record flattening effect of vacuum helps the stylus tracking correctly in the groove, more than avoiding "slipping" of the record on he platter. Just my unqualified guess !
Something you could test with the proper tools ! The RoadRunner "gadget" can assist you in diagnosing bearing problems, belt slippage and unstable power sources, just by monitoring in the background.
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Why do you not consider these to be proper tools? Have you ever used either one? The RoadRunner came with the table and I think comes with the AS2000. I also used the Micro strobe disk.
Again, these tools can be used to set the speed and can be very useful, not as an indicator of sound quality. The RoadRunner is a digital tachometer. IMHO all we need is the strobe disk, all else if for the fun of the hobby. In the particular case of the TechDas AF1Plus the incorporated tachometer can be used to set the belt tension - for those who do not want to set it by listening to their preferred sound.
Certainly, but maybe the record flattening effect of vacuum helps the stylus tracking correctly in the groove, more than avoiding "slipping" of the record on he platter. Just my unqualified guess !
The vacuum use shows in wow and flutter measurements and even in noise. I saw such data long ago on the Luxman turntables in a magazine review - and Hideaki Nishikawa specifically says so.
Surely - the same way a good inexpensive strobe does. But our ears should be even more sensitive!
There’s a tension range that speed remains constant and sound character will change it’s at tension extremes ie too tight or too loose where speed and stability is adversely affected. I find the width of the belt to have equal or even more of an effect on sound character as well.
Both the RR and a good strobe and disc are tools to help set the platter speed desired. They can also help with measuring speed variation and instability, a tach is a better tool IMO for this purpose.
david
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Vacuum hold down has a dampening effect and you hear it immediately when applied, if or how it affects w&f is debatable.
david
Yes! I've been saying this as well. Stable accuracy and low noise are, imo, the key functions of a turntable.
Yes, the GPA whitepaper on the Monaco turntable is no longer available on their Web site. Alvin perpetually claims that he is re-writing it. A PDF copy is attached.
Turntable speed accuracy
Record grooves contain only amplitude information and no frequency information. The frequency information of the record is generated by the speed turned by the playback device. Any deviations, changes or errors in the speed accuracy during playback will change the pitch of the signal retrieved by altering its recorded frequency. Simple fact, the more accurately you turn the record the more accurate the frequency/pitch reproduced and hence the lower the level of distortion and the greater the level of realism.
- Alvin Lloyd
Edit: The attached whitepaper is circa ~ 2013, though I don't have an exact date. It was written prior to release of the Monaco 1.5. Technologies and the measurements they yield changed significantly since original publication.
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for me a very interesting and important part of the turntable. I had a longer debate with Nishikawa on this. he explained the different forces effecting the belt and the ratio of with and length (free length between platter and motor, length around the platter) effecting the forces. The Aramid / Kevlar belt he is using (MS SF-1 or SF-1L or actual @TechDAS) structure is designed to work in an optimized way to handle this forces.
The change from the Micro Seiki SF-1 belt to the thin Micro Seiki Kevlar string is easy to hear.
Changing from there to soft rubber belt (like the white Clearaudio) is a big difference in sound, specially on piano.
I am not sure of any of the different belt Designs would have an effect on constant platter speed, but the audible effect is obvious.
Which do you prefer
?Staying with top line MS turntables and high mass platters once adjusted I don't see any speed fluctuation differences between the belts. Conditions change once we're dealing with 15kg and lighter platters and again dropping below 9kg is another paradigm, sonically and mechanically. Of course every other aspect of the turntable design and materials are always in play too but just limiting the conversation to belt effects.
david
david
Let's just say that after reading Alvin's paper there's quite a bit that I disagree with and important elements of belt design that he's conveniently left out. Of course the elephant in the room isn't how many times you measure the speed and how many adjustments you make to reach a numerical constant that he avoids discussing. What's also left out is how constant does platter speed needs to be, we certainly don't need 3 decimal points. How much variation with 2 decimal points is really audible? One thing that I do agree with which he touches on is the quality of the motors currently available for belt drive use, they present their ow set of challenges that need to be addressed and they're not in many designs currently.
david
I remember meeting AJ Conti when I visited him to pick up a My Sonic Labs cartridge. He took me into his back work room where he was testing new turntables tonearms and belts.
he told me the belt thickness matters as well as the amount of “free“ belt between the motor pulley and the platter. This had to do with the stretch of the belt and how much belt contact there was with the two round surfaces.
My old SME turntable had very little “free“ belt surface. The motor pulley was very close to a sub platter below the main platter and there was a high degree of belt tension.
I suspect good turntable designers understand that everything matters and pay a lot of attention to this.
he told me the belt thickness matters as well as the amount of “free“ belt between the motor pulley and the platter. This had to do with the stretch of the belt and how much belt contact there was with the two round surfaces.
My old SME turntable had very little “free“ belt surface. The motor pulley was very close to a sub platter below the main platter and there was a high degree of belt tension.
I suspect good turntable designers understand that everything matters and pay a lot of attention to this.
What is your criteria for labeling something a proper tool or a gadget? The RR tach is a lab quality instrument that measures the speed to 3 places right of the decimal. What you do with that accuracy and precision is up to you, just as with any quality instrument. Many users have diagnosed and corrected problems with their analog rig that previously went undetected, but once corrected, the sound quality improved significantly.
Is a strobe disc a gadget or a tool? If you use a mains powered light, it's not even a very useful gadget IME. You need a crystal controlled light source to have any kind of accuracy or stability.
How large of a speed error do you think you can see with a strobe disc? A large diameter disc (12") will drift ~0.1" at the perimeter (about the thickness of a nickel) per rev with a 0.1RPM speed error; surely that would be visible unless your eye sight is impaired. Smaller diameter discs will show less drift at the same error.
A speed error of 0.01 RPM with the same 12" disc will only drift 10 mils (about the thickness of card stock) per rev; I doubt most people could see that unless they had a stationary standard and watched the disc for several revs. 0.01 RPM error is ~.03% or less than one musical cent, the standard most professional musicians tune their instruments to.
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Slip between the LP and platter, if it exists, must be extremely small and easily corrected with record clamps or vacuum hold down. Even without those, there is significant surface area and friction so I doubt it could even be measured.
The most significant factor affecting platter (LP) speed on belt drive tables is belt creep; unlike belt slippage which can be cured with proper tension, belt creep is a necessary byproduct of using a smooth belt and cannot be eliminated entirely, though it can be reduced. Belt creep is caused by the unequal tension on either side of an elastic belt.
Tables with subplatters suffer from increased belt creep because the limited contact area requires higher tension in the belt which exacerbates the problem.
Thank you for your input Bill, you always have your facts straight, from personal experience in design and manufacturing !
The instrument becomes an audiophile gadget according to the way people use it. In this discussion as long as the instrument has an accuracy that is not needed for the purpose - setting the speed of the turntable - and we have equivalent almost free ways of setting the speed with the needed accuracy. As you know strobes are extremely sensitive - they are integrating devices and the error is cumulative - much more than the quoted 0.1 RPM, I have seen several reports of 0.01 RPM (.03%) and mains frequency is accurate enough for this purpose. As you wisely say we need a stationary line - even a shadow is enough for this purpose. But if someone tells me his listening pleasure is much reduced when listening at 33.30 compared to 33.333 rpm I will be the first to recommend him the electronic counting devices.
Please read our post exchange on this subject in full - I consider people are free to use whatever they want on their systems. But when I read posts correlating differences in speed due to stylus dragging with turntable quality I become more critical, particularly when people suggest it is an humbling experience. As always on these matters, IMHO and YMMV.
BTW, I am also guilty of systematically using "gadgets" in my system - for example an infrared thermometer to check temperature differences between channels of amplifiers and a voltmeter to check the balance gain between channels or laser measuring devices for speaker position alignment. But in my defense I will say I use industry standard quality instruments that I need for other purposes, not audiophile specific products.
Please note what is mostly considered for sound quality are the stylus induced LP micro accelerations against and in favor of the circular movement , not the average slip that is non existent according to measurements, as you say. Some people say that such thing does not exist, others state that they are of great importance.
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