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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
atmasphere's avatar
atmasphere
12,173 posts
 
You apparently believe that all separate arm pillars are the same regardless of size, weight, construction, density and supports.
The only reason an arm pillar can
move in different planes and rates
is if it is inadequate.

They all have one thing in common: they relay on the surface on which they rest. If this surface has any motion that allows the pillar to move in a different plane than the bearing of the platter, it makes no difference how well the pillar is constructed. Its a basic engineering flaw. I have explained this before.
What was this pod that Atmasphere used and how is this motor noise relevant?
We are not talking about motor noise here! Please re-read my first two posts- I am wondering though if I need to clarify in some way due to the obvious misunderstandings I have encountered!

You are totally wrong because I'm asking for normal day by day listening enviroment in real home audio systems, I don't care about lathe or about your self targets. YOUR TARGETS ARE NOT THE AUDIOPHILE TARGETS. GOT IT?
Oh I got it alright. What you don't seem to understand is that the lathe is an extremely high quality turntable- one with a massive platter, massive plinth, extreme platform and powerful drive. But a turntable nontheless, and one that stands up to any turntable made today. You could easily use it for playback only. So you are incorrect- my targets are the audiophile targets. You need to understand this, but right now I am thinking that you have an monetary investment that prevents you from doing so.
well, with all respect to him and you he is not a regarded TT/tonearm designer and for his posts neither an audiophile.
Actually this statement is false as well. It might interest you to know that Tri Mai of Triplanar was an employee of mine years ago. Further, we've been selling a turntable for about 15 years. It started as a modified Empire 208. Its expanded beyond that now and the result is we have a copycat who was a customer of ours and the price of used Empire 208s has skyrocketed on our account. That sort of influence does suggest some regard. I'm also an audiophile- that's why I do these things. Please try to stick to the facts rather than creating hearsay.

What I have been discussing here is a pretty basic engineering principle. It is not hard to understand at all. Anyone with a mechanical engineering background will agree with me instantly. I suspect those that don't have a monetary investment that forces them to resist, but this would be like resisting Ohm's Law, if you will pardon the expression.
fleib
1,124 posts
 

I think there is a fly in this ointment:

**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.**

Air borne vibration will hit the record/platter directly, as it also hits a plinth and arm. Any such vibration transmitted via the plinth will arrive after the event. How will this insure coincident behavior between arm and platter?

This isn't an automobile where both wheels are being turned at the same time. This is transmission of movement through time, and record rotation does not stop. It seems like this is the same old formula for sprung tables where movement must coincide.

Evidence or lack of, points to high quality and good execution as the winner. Think I'll go with Frank Kuzma and Torqueo Audio on this one.

rauliruegas
13,129 posts
 
Dear @atmasphere :  """  but right now I am thinking that you have an monetary investment that prevents you from doing so. """

Wrong again, my very little investment has nothing to do with. This discussion is not a contest, here no one wins but all, so as usually in you don't try to win but to understand to some of us that in my case have a higher ignorance level than you.

As some others posted you are intuitive more than scientific in this subject.
No one of us audiophiles have a lathe at home but normal TTs but because in your  simple  " test " you say that appears a " coloration " then in any inferior/normal home audio system things must happen too. That's what you infere but can't prove it.


"""  Actually this statement is false as well.   """"

could be but I think that no audiophile in this thread know you as a " well regarded " TT/tonearm designer/manufacturer. Please no ofense intented, for me even what you posted still no well regarded TT/tonearm manufacturer at least not at the same level as you are as tube elctronic designer/manufacturer.

Anyway, thank's for your reply.

Regards and enjoy the music,
R.
atmasphere's avatar
atmasphere
12,173 posts
 
Air borne vibration will hit the record/platter directly, as it also hits a plinth and arm. Any such vibration transmitted via the plinth will arrive after the event. How will this insure coincident behavior between arm and platter?
Again, for what, the 4th time? The platter and arm must move in the same plane and frequency, should there be any movement at all. Likely this would be airborne induced. If the base of the arm can move in a different plane or frequency, the result will be interpreted by the pickup as a coloration or noise.

For this reason the plinth must provide absolute coupling between the platter bearings and the base of the arm, and also must be completely dead (free of vibration) for best results.

In the case of an arm pillar you have essentially a poor plinth. This is because the mass of the pillar will simply not be in the same plane and frequency as that of the surface of the platter. Since the cartridge is essentially the interface, its stylus must make up the difference between the motion of the pillar and that of the surface of the platter. This insures that there will be a coloration. Please note that the platter does not have to be spinning for to be measurable.

As some others posted you are intuitive more than scientific in this subject.
No one of us audiophiles have a lathe at home but normal TTs but because in your  simple  " test " you say that appears a " coloration " then in any inferior/normal home audio system things must happen too. That's what you infere but can't prove it.

Oh I can prove it alright- and I reported how that was done. It certainly is intuitive and also scientific. Sorry I didn't record the measurements; at the time I didn't think anyone but ourselves would be interested.

Raul, if I might be so bold, you are accusing me of being intuitive and not scientific, despite the fact that I made measurements and my comments derive from those findings, while those my accusers have none!! Does anything strike you as wrong with that picture??

When we were developing the Atma-Sphere 208, we started with a plinth that was really terrible (the stock Empire plinth). We found that by treating it with damping materials, it got better, but was far better when we replaced it with a plinth that was machined of solid metal. The benefits were enormous- this made the machine far less susceptible to the volume of the stereo as it was playing in the room; bass was improved and so on.  At that point the plinth was machined out of solid aluminum 0.75" thick.

We found that by installing a brace between the the mount for the platter bearings and the base of the arm that there was further benefit.  Now if the pillar theory was correct this would not happen- improving the coupling would make it worse! This is science after all.

halcro's avatar
halcro
2,664 posts
 
Since the cartridge is essentially the interface, its stylus must make up the difference between the motion of the pillar and that of the surface of the platter.
"The motion of the pillar"......
There you go again. Nobody is claiming that a "moving pillar" is good but you have simply assumed that ALL pillars move because you yourself have used a 'moving' pillar (which you still refuse to disclose despite my three attempts to wrest it out of you).
A properly designed armpod sitting on a well isolated rigid base/shelf/plinth will NOT move despite your ill-informed protestations.
If I had an oscilloscope (and knew how to use one)....I would measure the three arms fixed to my Raven plinth and the three mounted on the armpods.
It would be interesting to see your arguments if these measurements contradicted your 'theory'....
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