Nude Turntable Project

Raul,
Since you have discovered a turntable that reduces distortions considerably over what you have been using, then surely that renders your views on the best cartridges moribund. You may well have written off many cartridges that you thought were not neutral, but in fact were highlighting turntable distortions.
Are you now going to re-review the 200 odd cartridges that you thought were no good?
Agree with Lew from personal experience marble ( sharp upper midrange resonances ) and wood ( dull, turgid ) are very poor plinth materials.
Also agree with Lew re the SP10mk3, I have 3 friends who have owned these for many years, and the improvement over the SP10mk2 is huge. I would rate the L07D as superior to the SP10mk2.

Victor 101 -
Could you get rid of the flimsy bottom cover completely and mount the nude deck via an inverted tripod ? It doesn't look particularly rigid from the photos.
Potentially could you remove the internal transformer and some of the electronic boards from the main chassis and mount them separately to eliminate as much vibration as possible. Make sure all internal joints are as rigid as possible.
If you check out the Cotter and Kaneda versions of the SP10mk3 you can see what is possible in terms of stripping down to the bare essentials.

Obviously if you cant hear much difference between a copper mat and a pigskin mat, then your system is either not very resolving or it is too highly coloured to hear differences in components.

Lewm,
My take from his description is that he unmuted the preamp when MC was selected with the volume up and a MM installed - hence this probably blew the phono stage.
Now the feedback he referred to in the other thread could be any of physical, acoustic or electrical. We dont have enough info as you say.
Physical - just put the TT on a rubber sponge and see if it changes the level of feedback, if so this suggests physical. Swap the TT's around and recheck.
Electrical - could be earthing related or could be adverse reaction from combo of cartridge & 2.5 metres of Cardas litz, ie tuned circuit from those cartridges and cabling is upsetting the phono stage.

The Nude Turntable Project is a modern fairytale based on an adaptation of "The Emperors New Clothes" by Hans Christian Andersen. Everyone looked at the new NTP with wonderment, but could not see that in reality it wore a cloak of many colours that only a child could see.

Halcro/Pryso
We are in agreement on the "stability" of 3 feet.
My comments on stability are in the context of draining unwanted energy using single point mechanical grounding. I also assume the tripod is correctly designed for weight distribution to give stability and deal with rotational energy around the central axis. I also assume we are not driving the TT down to the grocery store and we are not in the habit of sitting on it.
Very few surfaces that the gear is mounted on are truly level, and in that context 3 feet will naturally load predictably, whereas with 4 or more feet they will have to be adjusted precisely to provide predictable loads through each foot. This is almost impossible unless you have pressure pads under each foot. The Mana stand manufacturers' recommended set up procedure for their 4 legged stands were to adjust the 4 feet with a stethoscope and tapping technique. Imagine doing this on each shelf as well as the feet ! And if you have a wooden floor that moves, you'll need to retune them each season.
In my 30+ years of audio I have applied the Goldmund mechanical grounding principles on all my components ( and many others ) and in all circumstances converting equipment ( TT's, amps, speakers ), speaker stands etc to 3 feet, single point mechanical grounding has yielded significant improvements in clarity, focus and the removal of resonances and tonal distortions.
In the Goldmund amplifiers, the mains transformers are grounded directly by bolting the transformers to the Goldmund footer, and the transformer is attached to the chassis by lossy connectors. The electronic circuitry is directly coupled to another of the 3 feet for optimum grounding and that foot has a lossy connection to the chassis. The net outcome is that each of these sources of resonance are single point mechanically grounded, and separate from each other, even though they exist in the same chassis. The chassis is decoupled from the others and grounded through the third leg. With non Goldmund amps the "alpha" leg is best placed under the mains transformer which is usually the largest source of resonance.

08-26-13: Richardkrebs
From reading here it seems that those that prefer hard supports make them all out of the same material. I believe that this arrangement can be improved, if your goal is to wick energy out of the TT structure. By using, say, three identical hard feet you are creating multiple paths to the shelf (ground). This is the electrical equivalent of an earth loop.

This is certainly not new.
The seminal article for mechanical grounding in audio equipment as applied to turntables was the Technical Report by Martin Colloms of the Goldmund Reference published in Volume 51 of The Absolute Sound magazine in 1988. Colloms undertook a complete dissection of the design of the Goldmund Reference including the single point grounding methodology that Goldmund employed. I would highly recommend anyone interested in TT design obtain a copy for reference. Some of these mechanical grounding principles were deployed to their entry level products such as the Goldmund Studio that richardkrebs owned.
Each time there is a change in materials some energy passes through and some gets reflected back. For example if you have a mat on a platter, then some energy will pass through from the mat to the platter, but some energy will reflect back to the record/stylus and smear the sound. This is basic materials engineering.
Providing properly designed pathways to drain unwanted energy from the stylus, record interface through the platter to ground in order to prevent coloration from energy reflecting back into the record and stylus has been around since the 60's, moreso in Japanese audio circles.
The Final Audio Parthenon from Japan released in 1971 is essentially a nude turntable with defined energy paths from stylus to ground. The designer Kitamura explains that the amount of energy generated by the interaction of stylus and groove is much higher than required to drive the coils, and therefore unless the balance of energy is drained to ground, it rebounds and resonates the turntable, arm and cartridge, superimposing resonances back into the playback. This is documented in a review of the Final Audio TT in TAS Volume 8 #30 in 1983. The absence of resonance, which results in a clarity and density of tone unparalleled by other TT's I have auditioned such as the Goldmund, Micro Seiki's. SP10's, L07D's etc is one of the primary reasons I purchased the Final Audio Parthenon.

08-29-13: Ct0517
If I understand you are using three leg supports under your triangle TT.
One is the "alpha" leg the leader for energy transmission, while the other two are slower followers? Are you not worried about energy in the plinth getting built up in those two areas with the pvc legs? Did you have a way to test this other than by listening?

08-29-13: Richardkrebs
Like your Alpha leg analogy. Actually, with the other two feet, we are trying to block energy transmission as much as possible although in practice I doubt that this can truly be done.

Actually it does work.
With electrical grounding the signal always finds the path of least resistance.
With a mechanical ground, as discussed, providing a single path to ground results in a cleaner dissipation of energy. Mechanical resonances and disturbances will find the path of least resistance to some degree, but there must be a logical path in terms of materials selection, transmissibility etc from platter to ground to minimise backward reflections. In the richardkrebs example the resonant behaviour of the hard footer will result in a specific resonance absorption and transmission/reflection profile, whereas the soft feet will attract a resonance absorption and transmission/reflection profile that is quite different. If one were able to put together a mathematical model of the structure and materials composition, then minimising the resonant behaviour and backward reflections can be calculated quite easily and would be more reliable than listening since no system exists without colourations due to room or other equipment..

The table must have been 20 years old back then. Meaning the concept is at least 50 years old.

Ah yes - the tripod. A tripod provides stability against downward forces and horizontal forces and movements about horizontal axes. The positioning of the three feet away from the vertical centre allows the tripod better leverage for resisting lateral forces.
Been around since the Mycenae age - the 16th to 12th centuries BC. Had I been around at that time I would have used it in my first TT.

09-02-13: Ct0517
Richard – thanks for turning me onto the “alpha leg” :^)
I may try it with the sp10 setup later. One Stainless Steel leg and 3 PVC or other slower material legs.

With regard to your proposed 4 legged experiment, it appears that the physics and engineering principles underpinning the optimal mechanical grounding principles have been overlooked.
A tripod is inherently more stable than 4 legs. A tripod distributes the weight evenly around the centre of gravity across its 3 legs. This is why cameras and theodolites are usually mounted on tripods, they are more stable. Note also your Verdier TT uses 3 feet to take advantage of this principle.
The use of a grounding leg plus 2 non grounding legs to achieve a single point mechanical grounding works far more effectively with a tripod ( 3 legged ) configuration. The Goldmund Reference Technical Report in the Absolute Sound magazine, issue 51 has an informative discussion for those wishing to understand the principles of mechanical grounding.

08-27-12: Dover
Victor 101 -
Could you get rid of the flimsy bottom cover completely and mount the nude deck via an inverted tripod ? It doesn't look particularly rigid from the photos.
Potentially could you remove the internal transformer and some of the electronic boards from the main chassis and mount them separately to eliminate as much vibration as possible. Make sure all internal joints are as rigid as possible.

It is pleasing to see my suggestion in August last year to remove the flimsy bottom cover being successfully trialled at last. Thanks to all who have tried it.

09-10-13: Halcro
Despite the availability of accelerometers and other devices designed to measure and quantify vibrational energy and its transfer within materials…..I have seen no scientific evidence to support the many statements made by audiophiles on the nature of ‘vibration draining’ in regards to turntables….and any quantification of such?

You appear to be saying that the "improvements" you claim your new TT support structure are merely a figment of your imagination since you state "I have seen no scientific evidence to support the many statements made by audiophiles on the nature of ‘vibration draining’ in regards to turntables"

My view is that there are several sources of unwamted noise and vibration in TT's. That is one of the reasons that TT manufacturers publish noise floor specifications in the form of xxdB.
When playing a vinyl record, the stylus generates noise and vibration as well as the music you hear, resulting in vinyl record wear and stylus wear.
Most turntables have a platter that uses a spindle and thrust bearing to provide the ability to rotate. When the platter bearing rotates, this generates noise. Worn bearings are a direct consequence of this friction.
Both of these phenomena are a source of vibration and noise.
In order to "see" it, I would suggest you purchase a stethoscope and have a listen to your turntable, whilst it is working. Then have another listen when it is not working. This simple experiment may be revelatory for you.

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.

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.

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 ?

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.

09-19-13: Ct0517

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.

Your recollection is not correct. I have not used the words "set up bearing" and "oscillated" in the context of the Verdier. I have not heard a "fake" Verdier whatever that is.
I understand perfectly how the Verdier works, and there have been many iterations since the first Granito based one came out..
Suggest you read up on the Verdier. http://www.jcverdier.com/ADSL/platineV.html

Hifi News Review - "Incidentally, the bearing tan be fitted with a bail and thrust plate, by-passing the magnetic support. but apparently it doesn't then sound as good."

You might also like to check out Dertonams comments as suggested regarding the use of a ball :

04-01-09: Dertonarm
Lewm, two magnets rotating in a horizontal = planar sphere do indeed produce an eddy current field.
The Platine Verdier folks and dealers will hate me for this .......anyway:
The current La Platine does feature somewhat lower quality magnets (compared to the old Focal magnets used till 1990/91 - that particular magnet was no longer available when Focal changed to the "6-tablet-magnet" - design invented by J. Mahul for the 15" woofers in early 1991) - thats why they promoted the ball to be inserted in the top bearing shaft hollow. To stabilize the vertical movement of the platter (in mid-90ies production was a tendency to instable magnetic field and often in loss of magnetic force causing many Platines in europe (and I suppose elsewehere too) to "oscillate" (= being unstable in height of platter)). To solve this problem the "top ball bearing shaft" was introduced (well, the hollow was there before, so they just put in the ball - smart move). That particular problem never occured with pre-1991/92 Platines. However the eddy current brake effect is no longer as dominat as it was in the original version with much better and more homogenous magnets.
Dertonarm (Threads | Answers | This Thread)

With regard to my comments on weak motor, the Final Audio can pull the 22kg platter/mat/clamp to speed in less than 1 revolution. The Verdiers that I have seen and heard do not have this drive power. I know a couple of Verdier owners who have replaced the motor drive to good effect. The Final also has a correctly designed pulley for thread drive with self centering profile.
The original Verdier came with the option of a belt or linen thread ( or nylon according to one review on the Verdier website ). The optimum pulley profile for a thread drive is a concave face so that the thread self centres. Running a thread on a pulley with a flat face can result in instability of the thread tracking as it can ride up and down, or will find a natural position either at the top or bottom of the pulley, depending on how accurate the pulley is in terms of congruency to the platter edge.

09-19-13: Lewm
I've often wondered how the heck they can keep the thread from slipping down the smooth sides of the platter.

Tension and a correctly design pulley ensures that thread remains stable as above.

09-19-13: Ct0517
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 ?

The origins of the term ground zero began with the Manhattan Project and the bombing of Japan. The Strategic Bombing Survey of the atomic attacks, released in June 1946, used the term liberally, defining it as: "For convenience, the term 'ground zero' will be used to designate the point on the ground directly beneath the point of detonation, or 'air zero.' William Laurence, an embedded reporter with the Manhattan Project, reported that "Zero" was "the code name given to the spot chosen for the atomic bomb test" in 1945.
This forum is a sharing and examination of ideas, not a war zone.
The use of the term Ground Zero is perhaps unfortunate.

Ct0517

09-19-13: Ct0517
Dover .... 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 ?

Thought you might like to have a look at a Verdier on the official Verdier website with the thrust pad and ball option.
http://jcverdier.me.pagesperso-orange.fr/nouvellepage2.htm
It is not a fake. It doesn't oscillate. JC Verdier does know what he is doing.

Fyi Callas also do an upgrade kit for the Verdier to enable the adjustment of the ball precisely such that the platter is mechanically grounded, as per the Goldmund philosophy, but the weight borne is very very tiny, just enough to ground the platter. Many folk prefer the sound of the Verdier with the platter mechanically grounded to dissipate energy, and with a decent aftermarket motor and power supply to improve the speed accuracy and timing.
Naturally there will be other folk who prefer the more mellifluous and less precise sound of the Verdier with standard motor and non grounded bearing.

09-21-13: Lewm
The Verdier is NOT "nude" by the original definition put forth by Halcro after Raul. (Please go back to the beginning of this thread.) Nude means or is a synonym for "no plinth". No plinth means that those who adopted the approach mounted their tt chassis' on "feet", most typically the AT616 feet, with no physical union except gravity between feet and chassis.

Of course with the "nude" approach, the shelf is the plinth, as both the TT and armpod are coupled to it, unless the feet are levitating, or you are reinventing the English language.

Furthermore Halcro's Victor motor & platter are bolted to a flimsy chassis adorned with copious electronic boards and transformers, which, in turn are attached to the new stainless steel frame.

One could argue that the flimsy chassis or the chassis and frame is the plinth in this instance.

Ironically the Verdier ( and Micro's,Melco's & Final Audio) are more naked than the pseudo nude Victor because they are not mounted in a flimsy chassis and are not adorned with electronics and other unnecessary paraphernalia.

Therefore I suggest you have misappropriated the use of the word "nude", and should find a more appropriate word to describe the not so nude Victor.

Ct0517

09-27-13: Ct0517
I am now going fishing Henry. I will be using a Cordell CC Shad Green/Yellow to see if I can snag a lake trout

This pic is only a few days old

The hit was real.
The fight with 4lb pound line was real.
The landing and pics are real.

Are you sure that trout is not fake, there are a lot around...

Meanwhile this from my last visit to the deep south (latitude 46 degrees), no dover sole there, but enough kai moana to keep the whanau replete. One of several.....
Fishing for the Iwi
Savoured whilst listening to Schuberts Trout Quintet - Schiff/Hagen Quartet on Decca.
Well seasoned & accompanied by Rudi Bauer's excellent Quartz Reef Central Otago Pinot Gris.

09-14-15: Halcro
...I have just brought in a Victor QL-A7 from Japan for my son (who has recently dived into HiFi and vinyl).
Listening to this in my system (with a Signet TK-3Ea/155Lc cartridge) was a sobering experience.
This $600 table literally shamed the belt-drive Raven AC-2 loaded with mega-dollar arms and cartridges.
It also sounded stunningly better than my 'nude' TT-101 and TT-81 Victors (also with their mega-dollar arms).
This salutary experience has caused me to reflect on the wisdom of my 'nude' turntable mounting. The heavy wood plinth of the QL-A7 combined with the four large mildly compliant feet appear to bestow upon the performance, a depth and palette somewhat greater than is extracted with the steel cradle and spiked feet of my 'nude' mounting.
Changes are in the wind....👀
Halcro (System | Reviews | Threads | Answers | This Thread)

Halcro in my view you should purchase another QLA7. Based on your comments above this would give you a benchmark to aspire to. If you could duplicate the arm/cartridge then you will have a "constant" against which to analyse any mods to your TT101.

MDF today is just timber dust that is glued together.The glue is very expensive so in the manufacturing process they put in just enough glue to stabilise the outside faces of the board. In the centre where there is very little glue there is no structural strength at all.

The Victor plinths appear to be more like the chipboard used in speakers in the 70's.This is quite different to modern MDF. From what I can see on the net the CLP2D Victor plinth appears to use layers of chipboard, and from the dark lines I can see, it would appear that they may have used layers of chipboard with each layer being veneered on both sides. The QLA7 appears to be a simplified and lighter version.

Fast foward to todays speakers - Dynaudio put forward that they can get a cleaner midrange out of MDF than plywood, but they veneer both sides of the MDF with hardwood veneer to strengthen the board.

An interesting material for plinths is Engineered Quatrz stone used in kitchen bench tops. Corian is basically a polycarbonate compound ( includes aluminium nitrate ( salt ) that is a fire retardant ). Engineered stone by comparison is around 93% Quartz stone and 7% Epoxy. It does need special blades for cutting but is much easier and less expensive than slate. Most decent bench top manufacturers use big router beds and if you draw up what you want including holes for TT, tonearm, screws etc they can cut everything for you very accurately.

Henry - yes - electrical feedback, not structure born. Try putting the whole thing in the granite bowl with the motor cover attached.
I think if Steve McCormack were running a direct drive he would have launched "WonderNappies" along with his TipToes.

Halcro - if the cover is tight, then I would run an earth wire to the cover and then just push it into the cylinder leaving a gap at the top such that it doesn't touch the main TT. As long as the cover is grounded to discharge any electrical buildup it works. You could spray some damping compound on the inside of the cover if you want to get rid of any mechanical noise.

It is also possible that the tonearm & tonearm cabling could be picking up rf from the motor.

A small point on earthing - I usually find I get a lower nose floor if I run the TT earths ( i.e. chassis, motor etc ) to ground through the power cable to wall if possible and run only the tonearm earth to the phono/preamp. In a single ended system noise from grounding or shielding is effectively in the signal path.