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Tonearm mount on the plinth or on Pillar ?

Folks,
I am looking to buy a custom built turntable from Torqueo Audio (http://www.torqueo-audio.it/). They have two models, one with a wide base plinth where the tonearm would be mounted on the plinth (as usual) and the second is a compact plinth where they provide a seperate tonearm pillar to mount the tonearm. According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT. My concern is whether seperating the tonearm from the plinth would result in a lesser coherence in sound ? Isnt sharing the same platform results in a more well-timed, coherent presentation ? Any opinions ?
pani
fleib
1,124 posts
 

***Now in a turntable how it plays out is that instead of being scary or dangerous, it works out as a coloration: the platter must be as tightly coupled to the plinth via its bearing as possible, in turn the plinth must be absolutely rigid and acoustically dead while coupling the platter bearing to the base of the arm (which in turn should have no play in its bearings). Any divergence from this formula results in coloration.

The reason is simple: if the platter has any other motion other than rotation (for example a slight up and down that might be imparted from the plinth due to room-borne vibration), if there is any difference between that and the base of the arm the cartridge will compensate (since the stylus has to stay in the groove) with stylus motion and therefore a coloration.

So if the arm is sitting on a separate structure from the plinth, it is open to motion in a different plane and/or frequency as opposed to the platter and plinth. You really want it to move in the same plane and frequency as the plinth so that whatever that motion is can't be interpreted by the cartridge.

I am often amazed at how poorly understood this concept is. ***


This concept is a gross oversimplification and isn't thought through.  Airborne vibrations will be imparted to the platter (record), plinth, and arm at roughly the same time. There will be a delay as these vibrations are then transmitted from one to the other. This results in additional smearing/coloration.  It could also result in greater amplitude and additional coloration.

This is not better. It's worse, assuming the pod approach is well done and resists cross coupling.  There will still be some cross coupling through the base, but it's less likely to produce cross coloration if the base resists vibration transmission and the pods are mass coupled.

It's a fallacy to assume that vibrations appearing at the main bearing are best transmitted to the arm.

***According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT.***

No good reason to assume this is false.

Regards, 



lewm
13,006 posts
 
It's remarkable how durable is this controversy over separate vs linked and how vehement are the opinions, one way or the other.  Pryso and Chris, for me, bolting the outboard arm pod to the plinth fits into my philosophy.   Fleib, your statement: "There will be a delay as these vibrations are then transmitted from one to the other. This results in additional smearing/coloration. It could also result in greater amplitude and additional coloration.", is for me a reason why optimally the linkage must be extremely massive and rigid.  Isolating the two elements does not seem to me to be a solution to the problem you cite. Most ordinary tt plinths don't cut the mustard on the criterion of linkage.  Take a look at the underside and "armboard" of a Kenwood L07D, if you want to see an example of what I think is a good way to establish proper connectivity.  Also, take a look at a modern Galibier turntable for another example.  By the way, I have long been of the opinion that a "plinth" that minimally extends out beyond the perimeter of the platter, IOW, a circular but massive plinth a la Halcro's latest or Thuchan's new slate plinth for the TT101, or the Galibier tt's, is optimal.  (There are many more commercial products built this way.) I suspect that the older traditional rectangular plinth which provides a large open flat surface out beyond the platter can induce colorations by reflecting sound produced at the stylus/LP interface back at the stylus, but it's just a guess.  Thus a "pod" for the tonearm is fine with me, but it should be very positively linked to the support structure for the tt bearing, if not directly to the bearing.  
fleib
1,124 posts
 

Lewm,

What is "proper connectivity" ? 

The physical (mounting) relationship between platter and arm must be maintained.  The plinth or chassis must be heavy, rigid and not prone to transmit vibrations.  Why?  So vibrations or movement of the bearing does not get transmitted to the arm?  So these vibrations get transmitted and the arm moves in concert with the platter?

It's nonsense.

Regards,

Ag insider logo xs@2x
rauliruegas
13,048 posts
 
Dear @lewm: """  It's remarkable how durable is this controversy over separate vs linked and how vehement are the opinions, one way or the other. """

Either, by theory or real tests,  some way or the other almost all of us talk about " colorations/distortions " .

The " theoretical " people ( like you ) can't prove those theories with out first hand real tests/measurements and the ones ( like me ) that already tested and made several comparisons in between TT integrated arm pillar and stand alone tonearm pillar neither have scientific measurements of what we are listening or not but the " testers " have a clear adevantage over the theoretical gentlemans: we can attest a " better/lower colored " quality sound level that for example you have not and can't imagine.

As I posted for a theoretical opinion can has value it needs first hand experiences in each one own audio system, if not your opinions are just: useless.

Now, is't easy to measure ( through a scientific methodology. ) the theoretical " additional colorations/distortions " you, atmasphere and the theoreticals ones supports?, I think not for any one.

We have to think how to aisle the specific  " colorations/distortions " created in specific by the sole integrated arm pod variable and the stand alone arm pod variable against all the other variables ( colorations/distortions. ) involved in the end result when the sound waves comes in the air and goes through our ears.

Who of you can make the measures that with certainty.

So and till today the best is to listen it as some of us did it or still do and with all respect for people like you just forgeret on this audio subject.

There are people like you that are willing to try it and some of them will try through the time but you are not even willing to try but always give the same theoretical statement with no single fact that prove it and that's why I posted is useless and with low value opinion.

I know, any one is free to give his opinion: valid or not. So you can go on with.

Anyway, stand alone tonearm pod or not in both " configurations " exist distortions of many kind. Wich configuration puts us nearer to the recording?, this's the question and main subject. No one is the Bible's boss.


Regards and enjoy the music,
R.



ct0517's avatar
ct0517
2,041 posts
 
@Atmasphere 

What is the vertical angle being cut into the disc where you work ?

thanks  
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