Nude Turntable Project

Banquo363, you beat me to it. BTW thanks for the report of trying your table without the tin can.

Halcro,

09-12-13: Halcro
And here is the equally famous Takai Lab Final VTT-1 belt-drive turntable similar to Dover's.....although he has the Parthenon model I seem to recall which is quite different to this one?

The Final in the picture is missing most of the TT. It is a VTT1 Platter & bearing with non standard Lead Console plinth, and a Pioneer DC motor drive. It is missing the original SPZ plinth and it is also missing the original sine & cosine wave regenerated power supply and original motor.
Here's an early Final VTT1 with the SPZ plinth.
http://www.hifido.co.jp/KWfinal/G0301/E/0-10/C09-43580-46106-00/
In my VTT1 the wine/cosine generator is separate from the motor and uses a separate power amplifier for providing motor drive.
The Takai/Final Labs preceded both the Melcos and the big micro's by 7-8 years. The Melco's are interesting - they use embedded titanium in the bearing assembly, and the thrust pad is mounted on a spring designed specifically to the platter mass. The platter uses the Okubo mass formula to obtain equilibrium and minimise bearing "friction".
The Takai/Final Labs have an inverted bearing, placing the platter centre of gravity well below the bearing point, whereas the Melcos/Micro use the conventional bearing. The Takai/Final Labs also use sine/cosine wave generated power supplies for the AC motors. The Melco's & Micro's are less sophisticated in this area.

Dover,
Thanks for the info. I tried Googling but there is sparse detail available.
That Final motor looks serious........

Is no one interested in the magnetic fields concentrated at the normal arc of the cartridge? It would be helpful and interesting if someone with a smartphone would install the Tesla app and repeat my experiment.

Is this a problem? Does it effect all DD turntables?

I have ordered mu-metal sheets to try and redirect the magnetism away from this area. More on that in a week or so.

Gary

according to this, it is a problem, Aigenga. I believe Lewm investigated these issues with his Kenwood.

Sorry I don't have a smart phone but next time friends come over I'll have them do it.

The symptoms of rfi and emi contamination that site articulates are certainly troubling. I don't detect them in my set up, but I suppose along each of the dimensions things could be better--so who knows. As I noted above, I stuck some pieces of TI Shield underneath my subplatter right above the motor cover. Perhaps that is doing me some good? And if I used a heavy platter mat I would use the shield directly beneath it--but the boston audio mat 2 wasn't heavy enough to flatten the piece I cut. I think the mu metal is thinner.

What does the app actually detect, EMI or "magnetic fields"? Those are two different phenomena. I would expect it detects EMI. I don't think this is endemic to every single DD turntable ever made; I would expect it is something to think about on a case by case basis with any particular DD. However, as Banquo mentioned, the L07D cognoscenti recommend implementing a shield between its motor and the platter. It seems to me that Kenwood already did that: the platter "mat" is actually a 5-lb piece of quarter-inch-thick stainless steel, which while not being a perfectly efficient shield, does act as a shield. Nevertheless, I did buy a piece of TI Shield from M Percy. I cut it in the shape of an LP and tucked it in under the stainless steel platter mat, so it does not show. I then was able to imagine that it made an improvement; I don't trust such uncontrolled observations when made by the guy who did the work and spent the money (me), but there you have it. One could do the same or similar for the TT101 or any other DD. A copper platter mat would do some good as an alternative. The SP10 Mk3 has a massive piece of bronze or brass in its surface, which probably affords some shielding. Unfortunately, last time I looked on M Percy's website, there is a notation to the effect that TI Shield is No Longer Available. I don't know whether that means it is out of production or only no longer sold by Percy. He does also sell ERS cloth, which could be made to do the job.

Note that any shield must be grounded to be fully effective. I am assuming that, since the TI Shield on my L07D is fully in contact with both the base platter and the SS mat, and since they are in continuity with the bearing, my shield is grounded. (TI Shield has layers of copper on both sides; it is quite conductive. Be careful.)

The app measures micro tesla or mili gauss - both seem to be measures of magnetic fields. If I said that I know much more than that I would be lying.

I don't yet know if I will cover the motor area - leaving ventilation space or make the mu metal sheets part of my mat, one way or the other.

Gary

Aigenga, what's the exact name of the app you are using?

https://play.google.com/store/apps/details?id=com.maxcom.magdetector&hl=en

I just did a quick search and found this for Android

I am using "Teslameter 11th" from skypaw on an iPhone.
Gary

Sounds like I was wrong in assuming the app measure EMI and not magnetic field strength, as "Gauss" is a unit of magnetism (but it might also be a unit of measure for EMI; I need to check). I have no evidence that magnetics is any problem with L07D or SP10 Mk3, the latter of which has a humongous magnet and a very powerful motor. Anything ferrous will block or absorb magnetic forces. When you did your measurements, was the TT101 fully assembled and running? Did you compare with and without the "pants"? Possibly blocking magnetic field from the transformer or motor is the primary or a secondary function of the pants, since we do know they are ferrous. ("Old Ironpants.")

The discussion of the awesome Final Audio tts and their relatives brings to mind another audio conundrum. Does a tt need a massive heavy platter to reproduce extreme low bass? Halcro may have an opinion on this, since he is running his TT101, which has one of the lightest platters I have seen on a TOTL DD tt, vs the Raven tt, which has a typical massive platter associated with the high end belt-drive tts. Henry, do you perceive a difference in bass reproduction between the Raven and the TT101? If so, in favor of which tt? Thanks.

Aigenga, looks be just a iphone app. I have a droid OS, was thinking if others do try it would be best to use same software. Have to say I would be skeptical of accuracy of an app for this application. The one I tried was finicky.

Well…I read the interesting article on RFI/EMI linked by Banquo. Whilst it deals specifically with the Kenwood L-07D turntable….I don’t doubt that its observations would also apply to most unshielded DD turntables?
Whilst the writer begins criticising the L-07D …

The tonal range is also reduced. The sound stage is compressed. Stereo separation is reduced….and there is a roll-off of the upper registers

……I hear none of these artifacts with the TT-101 compared to the Raven AC-2 and the Continuum Caliburn.
In fact……these are some of the areas in which the TT-101 playback excels……compared to other turntables?
I also hear no “wum wum wum” sounds through the speakers when the ‘brake’ function is activated.
My experiences with RFI/EMI problems are that if they are present…..they are audible. Simply place the stylus on the vinyl and turn up the volume way past that at which you normally listen. A hum or drone emanates from the speakers which increases as the volume increases. With my TT-101….I can turn up the volume to maximum without any extraneous noise whatsoever.
I am more concerned at the possible ‘unknown’ effects of the wayward magnetism inherent in those DD turntables? So I decided to do some tests on the actual ‘strength’ of this magnetism.
Using my trusty vertical magnet tester……I placed it on the bare aluminium Victor platter and felt its ‘pull’. Was it enough to hold the magnet whilst the platter spun?
Yes it was!
I then decided to try it with the Micro Seiki Cu-180 solid copper platter mat in place.
I was surprised to find the magnetic field was not deterred one iota by the copper platter and the little magnet stayed upright. Methinks the Cu-180 is a ‘fake’ gunmetal copy painted gold? :-(
Could this magnetic field extend through the copper/gunmetal AND a vinyl record?…..is the Pope catholic?
Next I tried to emulate these tests with the original Victor rubber platter mat and then the Victor 1mm pigskin mat directly on the aluminium platter and could not get the little yellow magnet to even stay on the surface….let alone stand at attention :-)

Does a tt need a massive heavy platter to reproduce extreme low bass?

This seems to be an interim conclusion by respected reviewers like Michael Fremer and Jonathan Valin but they obviously haven’t heard the TT-101?
The Victor can go deeper than the Raven AC-2 (depending on cartridge in use)……but more importantly…the bass can sound more natural, better controlled with less overhang and more definition.
Perhaps the physics is different with belt-drive decks….but the short answer to Lewm’s question is…….not in my experience. :-)

FWIW, "Gauss" are a unit of magnetism. EMI is measured either in Volts per meter or Watts per meter-squared.

I can't vouch for the app but the phone has a compass in it which has to be a magnetism detector. So if the app tells me that there is a concentration of magnetic field in certain places and if it is consistent in that reading across multiple tests under varying circumstances then I must believe that it is so. Likely the absolute measurements are not to engineering standards but I am not using the numbers only the relative magnitude of the readings at various spots around the TT.

I don't know if the strength of the field rises to a problematic level - might be cartridge dependent. I also don't know how a problem would present: noise?, loss of detail or dynamics due to magnetic interference? Maybe I'll be able to fix the situation and maybe I will hear a change. I'm skeptical that I will. Gary

Halcro,
there came out so many Micro Seiki CU180 metal plates out of China in the last years MS couldn't have produced in the golden (!) times of Japanese turntable building...

Halcro copper will do nothing with EMI on for RFI

Lawrence

Halcro, I would not expect copper per se to do much to absorb or block a magnetic field, except by virtue of its thickness which would just physically space the LP and the cartridge that much further away from the source. I am glad to hear your report on the comparison between the TT101 and the Raven. There are many in the audio community who say otherwise, and I never could figure out a scientific basis for their claim, that you need a very massy platter to have good bass reproduction. It seems to me that a combination of torque and well done speed control would be as good. If you will recall, Dertonearm once wrote here that at minimum, a platter MUST weigh 35 lbs for good bass.

Lharasim. Are you certain that copper is not an effective EMI shield? TI Shield, which is a documented effective EMI shield, is composed of three layers: copper/permalloy/copper. True, it does not work unless the copper surface is grounded. Perhaps it is the permalloy layer that does the work. I don't actually know.

I just went to the URL provided by Aigenga. The photos show exactly what I did, as well, to create an EMI shield for my L07D. However, I never heard any "wum-wum" when the brake activated, either before or after shielding was installed. That site is the one hosted by Howard Stearn, who is an orthopedist by day and an L07D Lover by night.

Halcro,
there might be only one conclusion, get rid of the Raven :-)
isn't it time for a change? I don't know about the value of these modern machines right now. I always went for technology, musicality and a rare design when going for tables. My tables kept the value, they instead increased. I really don't get it why some audio friends pay horrendous amounts for everyday tables which basically copy an originial, to the better?

Lawrence,
It was magnetism......not RFI/EMI that surprised me on the Cu-180 turntable mat?
The Micro Cu-180 is indeed non-magnetic.
My ignorance levels on electro-magnetism run deep.......but I'm guessing that there are materials which can act as 'conductors' whilst others are 'insulators'?
That's why the stainless steel of the 'cradle' I designed became 'magnetised' by the strong magnetic field and why the non-magnetic aluminium platter of the Victor becomes 'magnetised'.....or at least allows the magnetic field to pass through?
The same effect must be in operation with the Micro copper platter even though it is 3mm thick?
I can understand the rubber platter mat being an 'insulator'.......but a 1mm piece of pigskin being a sufficient insulator bowls me over.....
And why a 2mm thick piece of vinyl is NOT an insulator.....I don't know?
I'm sure someone will educate me?
Where's Al when you really need him?? :-)

You're right Thuchan,
There appears to be 10 times more Cu-180 platter mats available for sale.....even NOS ones.....than Micro ever made in their day?

Similar story with the Orsonic headshells....:-)
Aren't the Chinese great?

To be fair to Dertonarm Lew.....he was referring to belt-drive turntables with his 35 lbs platter comment.
His logic.....and that of many other belt-drive designers.....is that greater mass creates sufficient inertia in the revolving platter to overcome stylus drag?
He also advocates non-elastic string or thread drive instead of rubber which means that the platter is not insulated from the cogging of the drive motor.
This of course requires a superb motor design.
For a direct drive turntable with a quartz-locked servo motor.....particularly a positive and negative servo control like the TT-101......the lightest possible platter will make speed changes less perceptible than a heavy one.
A common mistake that critics seem to make when discussing quartz-locked servo control....is that the servo is always 'hunting' for the correct speed?
They disregard the notion that the speed is quartz-LOCKED. The speed is generally spot on and not 'hunting' at all. The only time speed correction may be applied is under localised untoward stylus drag when....as you correctly remark.....good torque and bi-lateral speed control come into their own.

Thuchan,
Don't get me wrong.......
The Raven AC-2 is an excellent turntable providing very stable speed control and superb analogue performance when set up correctly.
It has audibly kept level with the TT-101 until this last 'nudie' change I have made.
And in my 35 years experience listening to all the best turntables I could access.....the TT-101 is simply the best.
The fact that I have extracted a performance level from the Raven that is so close......speaks volumes I think?
I will not be selling the Raven :-)

I tried that droid application for magnetism.
curiosity got the better of me. Some "fun" observations.
I set the magnetism scale to the highest level so the bar would not peak.
Holding my phone in my left hand I took hold of a fridge magnet with my right hand.
I have a boatload of these now leftover from my ET2 magnetic damping experiments.
Sure enough as I brought the magnet closer it would register on the proximity graph.
Sort of like in the movies where they show crew in submarines with radar. As I came in closer the levels would go up.
So it does work - but how accurate is it ?

The sp10mkII first.
While holding it about an inch above the platter away from the cartridge it showed numbers in the 40's.
Turning the power supply on caused the number to jump to the 80's. Now the interesting part.
Pushing start reduced the number to the 40's again.

Lenco. unfortunately this test was ???? as the big magnet laden Dynavector tonearm sits on this table.
It started in the 40's and as I brought my phone toward the mid section of the Dynavector the scale would want to shoot way off.
Which leads me to ask myself. Dynavector is a well respected company. if they thought there was a problem with magnetism would they have built their tonearm to be joined with their cartridges ?

Verdier - the most surprising since it uses two very large magnets (shielded) for levitation. With my phone just above the big platter. The lowest levels observed in the teens and 20's.

Cheers

Which leads me to ask myself. Dynavector is a well respected company. if they thought there was a problem with magnetism would they have built their tonearm to be joined with their cartridges ?

Good question Chris.
One would think not?

Halcro, To reiterate, copper does not shield against magnetism, electro- or other, largely because, as you noted yourself, copper is non-magnetic. Also, electrical insulators that you list are not good insulators against magnetism. Stainless steel can be magnetized because it has a (low) iron content. Alu will be as good as rubber, i.e., not good. Distance from the source and ferrous materials are two ways to reduce the magnetic field.

Chris, I think you answered your own question re the Dynavector, if I understand you correctly. It seems there was no detectable contribution from the magnet at the rear of the DV pivot when your detector was at the headshell. Thus, I would think, there is nothing to worry about (based on the fact that you read the same value of 40-ish when the tonearm is not in the picture). Moreover, the DV magnet is actually two magnets held in place in apposition over the stabilizer blade that is fixed to the moving part of the tonearm. Most of the magnetic lines of force would stay localized to that area because of the interaction between the two apposed stationary magnets and the moving blade that is already deliberately created. Yes, I think DV knew what they were doing, as they have stuck with this basic design for nearly 30 years.

Same goes for the Verdier: it uses two huge magnets of opposite polarity to elevate the platter. The magnetic lines of force are therefore concentrated in that space between the two giant magnets. Stick your detector down there, and see what that does. Also, the thick platter gives distance from any possible problem up on the platter surface.

I guess Syntax might say that he is not surprised that you prefer the TT101 to the Raven for deepest bass response. I've never yet owned a BD tt with a platter that would meet Dertonearm's standard for mass, so I have no opinion (and in fairness, I may be misquoting the minimum mass, but the parameter "35 lbs" sticks in my mind). I did at the time take some issue with his explanation for the finding, which was not solely based on rotational inertia.

EMF Measurements

Using an EMF Field Tester, range 0.1 - 200m Gauss I found the following measurements interesting.
Highest EMF emissions from vacuum tube preamplifier.
2" above the power supply 23m Gauss
2" above the tube circuitry 8m Gauss
15" to the side of the preamp 0.1m Gauss
15" above the preamp 3-4m Gauss.

The conclusion is that it may be better from an EMF view to place the equipment beside the TT and not underneath it.

As regards to the magnetism tests, on my Final Audio Parthenon, which uses Copper mat, Aluminium platter, gunmetal & SPZ bearing housings and base, there is no magnetism measured at all - none.

Halcro, could it be that you enjoy the Victor more because of its magnetic personality ? Magnetism in ferrous metals can be masked through the use of chrome plating. Some of the Japanese high end tube manufacturers use this technique of a chrome plated and painted steel chassis because the common alternative, aluminium, induces hysteresis distortion in the electrical signal when aluminium is placed near an electrical flow.

I have seen the Technics SP02 DD motor in a cutting lathe situation; the motor was mounted about 2 1/2 ft below the cutting head and the platter was 50kg. This is probably the way you should build a DD. The alternative would be to convert your DD to a thread drive and mount it all in a non magnetic chassis.

Final suggestion for the Victor owners who want to dispense with the flimsy cover, why not build a faraday shield but mount it to the shelf, not the TT. This will provide shielding and minimise resonance.

I received a sheet of mu-metal magnetic shield today and installed it in my TT-101. Here is the Before image showing the interior damped with automobile damping sheets. Here is the After image showing the mu-metal sheet cut into shape and placed over the motor. It is not grounded, nor is the turntable.

The result is that the magnetic field has moved away from the tonearm arc area of the platter over to the opposite (left) side of the platter. It is also more intense on the left side than it used to be on the right side but I think that it doesn’t matter because it doesn’t reach the cartridge. Mu-metal can only shield an area from magnetism, it cannot destroy the field. It is like squeezing a balloon – the air just moves to a different area in the balloon.

Soundwise, I haven’t done any blind testing or even playing an album side with it and then playing the same side without it – which is how I like to do it. But, I did play a few cuts on a few favorite albums and was (perhaps deluded into) hearing a better audio image and clearer notes and lyrics than I expected. I got that dumb grin on my face that I get when my rig sounds great.

An easy tweek that I (almost for sure) believe in.

Gary

Lewm,
Syntax despises DD turntables and Idlers and eschews the qualities displayed by the big Caliburn belt-drive.
He also abhors MM and MI cartridges so crediting him with any knowledge of the TT-101 is like mistaking him for a man of discernment?

Dover,
Did you miss the point that with the pigskin platter mat in place....there was no magnetism at the mat nor the vinyl disc?

Dover, Did you mean "EMF" or "EMI"? The discussion has gotten a bit confusing with the interchangeable use of the terms "EMI", "magnetism or magnetics", and "electromagnetics". Different manifestations of the same phenomena but with different consequences. I think of "EMF" as "electromotive force" = Volts. Units would not be "Gauss", I don't think.

Of course you would measure no EMI (or EMF) near the chassis of your belt-drive, where the motor is way outboard on the other end of the long belt. That is to be expected. Do you think the magnetic field or the EMI measurable in the vicinity of the platter of some DD turntables is damns them all, as a class? I am not even sure there is any consequence to it, and if there is, many have shown that the fields can be shielded.

Halcro, I have no bone to pick with Syntax, but I agree on the observation that he and a few others who are countrymen to Thomas Woschnick do seem to revile his Raven turntables to an inordinately passionate degree. It seems strange at times. He did not insult the TT101 so much as he did insult the Raven. Did TW kick someone's dog?

Lewm,
I use the acronym above EMF to mean Electromagnetic Field. This will have an electrical component, measured in volts, and a magnetic component, measured in mG (milliGauss). The tester I used measures the magnetic component of an electromagnetic field in milliGauss.
With regard to the Q on DD's, I dont think it is ideal to have electromagnetic fields floating around the cartridge, irrespective of what type of TT is used.
Halcro,
Yes I got the pigskin. If I can get some from the local abattoir I'll try it over the preamp. Do you know if it is from an Australian Yorkshire or a Japanese Landrace ?

Excellent Design?

Of course :-)
But, my personal Favorite is Audiophile Rule No. 2

"when it sounds good to you, it IS good"

I'm wondering if Idlers exhibit the same 'magnetic' characteristics as DDs seeing how they also have motors etc under the platter?
I suspect that the EMT 927 would react "positive' to a magnet wandering amongst its innards.......especially with its steel supporting frame?
Are you able to confirm this for us Thuchan?
And Lew.....perhaps you could do likewise with your Garrard 301?

Dover,
Mine comes from Israel.....

Henry, Don't own a Garrard 301. Do own a highly modified Lenco L75. In fact the only parts from a stock Lenco that I use are the motor, the idler arm and wheel, and the platter. Where there is a motor, there is an electromagnetic field. Thus I am sure that one would be detected with a detector in the vicinity of the motor. However, I use the PTP plate, which is 4mm of solid steel between the motor and the underside of the platter. Moreover, there is about 2 to 3 inches of space between the motor and the platter, and the platter itself is heavy aluminum. So, the shielding is at least "pretty good", and the physical distance would help as well. These fields generally fall off in accordance with an inverse square law; the strength is inversely proportional to the square of the distance. In DD's with coreless motors, like the TT101 and the L07D, the potentially radiating elements of the motor are particularly up close to the platter.

Stick your detector down there, and see what that does. Also, the thick platter gives distance from any possible problem up on the platter surface.

Hi Lewm
I fear for the life of my 2 year old Samsung Galaxy if I stuck it in there. a little curious but not that much.....
My daughter just expensed a new IPhone to me and my son a Samsung Note.
They both turn 19 on Friday this week - how could I refuse.
My phone now needs to last a couple more years.
btw - Drinking age in Ontario is 19 - maybe they will buy me a bottle of wine in return.

I suspect any levels I measured came from the cartridge - I was only six inches away from it.

I am however surprised at Dovers comment.

I dont think it is ideal to have electromagnetic fields floating around the cartridge, irrespective of what type of TT is used.

I mean considering he uses a Dynavector tonearm and preferred ET2 Magnetic damping. :^)

Cheers

I currently have a L07d in a thousand pieces. It uses extensive complex shielding around the motors many parts. Quite necessary I think, since the coils are close to the upper platter surface and are oriented vertically, focusing their flux up and down as opposed to horizontally on some other designs.

Chris, the increase in flux strength on the SP10 MK2 when stopped is due to the brake solenoid. Powered at stop, off when running.
I don't bother with the brake at all, using the EM braking of the motor itself to pull down the platters speed at stop.

Chris, the increase in flux strength on the SP10 MK2 when stopped is due to the brake solenoid. Powered at stop, off when running.

two comments Richard

1) You confirmed that this app on my phone actually works. this is kind of cool.
2) I'm impressed with your findings.

I currently have an L07d in a thousand pieces.

I look forward to reading about how you fit an ET2 on that. :^)

But Boy, would I really like for someone like you to get yours hands on a thread drive design TT - NOT - a belt drive design that has been converted to thread.

I would love to read your impressions ...

Cheers

09-18-13: Ct0517
I am however surprised at Dovers comment.

I dont think it is ideal to have electromagnetic fields floating around the cartridge, irrespective of what type of TT is used.

I mean considering he uses a Dynavector tonearm and preferred ET2 Magnetic damping. :^)

Ct0517 - your comments are incorrect.
Though I own a Dynavector arm I have not used it for a long time. It is handily outclassed by my Fidelity FR64S, Naim Aro and Eminent Technology ET2 arms.
Please refer to my post in your ET2 thread...

05-16-13: Dover
By the way I still own a Dynavector 501 which has a very high horizontal effective mass, and whilst the bass is quite punchy, the musical timing, soundstaging, and resolution is well down on both my Naim Aro and Fidelity Research FR64S ( yes I own 2 of these as well ).

Another correction:
Very minimal magnetic damping is used on my ET2, none on the Denon 103 set up, and it is well away from the cartridge and cable. This too was explained in your ET2 thread.

03-03-13: Dover
The configuration I use is:
Decoupled counterweight in the horizontal mode ( spring bypassed )
Lightened tonearm
Minimal magnetic dampening

09-19-13: Ct0517
But Boy, would I really like for someone like you to get yours hands on a thread drive design TT - NOT - a belt drive design that has been converted to thread.
I would love to read your impressions ...

I agree, it is folly to convert a belt drive to thread drive, unless all the engineering principles on motor selection, pulley design and platter/bearing design have been revisited and are clearly understood. For example, the optimum pulley for a thread drive will have quite a different profile than that of a belt, as well as the motor design, power delivery and platter mass. An example of this is the Verdier, where the motor is not strong, and addressing this should be a prerequisite before converting to thread drive.
It is quite an ask to go from tinkering around with DD turntables to designing a thread drive. A thorough understanding of engineering principles would be a prerequisite. I would recommend you search on Dertonams posts on thread drive in this forum for authoritative and informed analysis of thread drive principles. Dertonam has had a wealth of experience with the Micro Seiki thread drive TT’s that were designed specifically for thread drive from the outset, as is the Final Audio Parthenon thread drive TT.

I just downloaded the Teslameter 11th App onto my iPhone and it's very interesting.
It measures an electro-magnetic field in either Micro Teslas or Milli-Gauss (1 Tesla=10,000Gauss).
Just sitting in my listening chair gives a reading of 43uT or 590mG whilst at the turntable platter I can get a reading from 92-over 200(cut-out point) uT or 590-over 2000mG.
Readings UNDER the naked TT-101 are all over the 200uT max limit.
The readings change with power on or off so a complex study is required.
Because of my 3 tonearms.....the position of each cartridge traverses a different path with the cartridge passing over the transformer reading the highest.
Of course...all the cartridges at their inner-groove points are directly over the motor coils and the reading goes off the chart in all these cases.

The interesting thing is no difference in sound is heard by me as each cartridge passes over different reading points...and the arm passing over the transformer sounds no different to the other arms in intrinsic quality.

As a side-note....in this months issue of Stereophile with the 2013 Recommended Components.....for turntables ranked A+ and A.......76% have their motors mounted in the plinth close to the platter.

If Thuchan can download this App to his iPhone and demonstrate that the EMT 927 provides plenty of magnetism.......it may be possible to make a case for the beneficial effects of this ingredient? :-)

Henry, Don't own a Garrard 301

Sorry Lew.....I knew you had an idler and was just too lazy to look-up your System Page.....
It would be interesting to check your Technics SP10Mk3 which has the motor with the most torque (power?).....?

Dover, Funny you say that about "converting" the Verdier to thread drive. Nearly all, if not actually all, the Verdiers I have ever seen have been using thread drive. I actually thought it was "stock". One well known emporium near me that sells Verdier places the motor about 3 feet away from the platter and uses a thread drive. I've often wondered how the heck they can keep the thread from slipping down the smooth sides of the platter.

Richard, You voiced my own thoughts on the pitfall of a coreless motor; the orientation of the magnet and coils is at 90 degrees to that of a conventional motor, and this would result in max field strength in the vertical direction. Plus, the coreless motor is very close to the underside of the platter, much closer to the platter than a conventional motor in a Technics or other similar DD. I've noted that the L07D motor is a completely discrete unit, sealed in a casing shaped like a movie version of a flying saucer. Do you think the casing is made of mu metal or something with similar shielding properties? If so, why do we perceive that adding another shield under the platter mat makes a further improvement?

By the way, the same might be said of the TT101 motor. It too is completely encased, top and bottom, maybe for the same reason???

Dover - imo each of us needs and has a reference point, a ground zero for this hobby and other things in life.
Without this anchor we become lost.
This ground zero is a little different for everyone.
For this reproduced in my room as far as source goes - my Studer deck playing 15 ips tapes is it for me.

here's why.

Before my Studer tech gave me back my tape machine he put on a tape that had different frequency notes on it.
He played each of them for one minute. It was rock solid in pitch. Never wavering. I wont get into its sonics here.

imo - a TT setup can come close, but will never be this good because other than all the many electro/mechanical "items" that need to be set up with the table, tonearm and cartridge - the record itself is so so flawed. oh you can try to setup things as best as possible for one record. But the next one will be different. I have hundreds in rows next to my listening chair that I randomly select from. What are you going to do.

So the record for the vinyl hobby imo is the Elephant in the Room.

Everyone loves to talk about their shiny TTs, tonearms and cartridges - the equipment. No one wants to talk about the source. Sorry for ranting on your thread Henry.

Dover
An example of this is the Verdier, where the motor is not strong, and addressing this should be a prerequisite before converting to thread drive.

imo - if you truly understood how this table worked you would not have made this comment. I guess JC Verdier does not know what he is doing. If I recall you discussed a Verdier in the past on this forum and it required the use of a setup bearing to run properly as it oscillated. Could it have been one of the many counterfeit ones around ? Its a very imitated and duplicated table. You need to be very careful. fwiw - I remember reading Syntax timeline testing the vintage Verdier - it was on the pass list. Cant remember the thread.

My Verdier and my other hobby tables are compared against my Studer in my own room real time - switching between the two.

So thats my Ground Zero Dover. Whats yours ?