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

Lew,

**To wit, there would be a great deal of movement of the LP surface, mediated by the suspension, that could not be followed by movement of the tonearm pivot, and this would generate spurious signals at the cartridge/LP interface. On a more micro level, this principle is operative in the relationship between any plinth, suspended or not, and any arm mounting system.**

Not true. On a micro level the vibrations would not make it between platter and arm with a high mass "dead" plinth. Part of the reason such plinths sound good is because they resist vibration transmission.

You think this engineering principle holds true under any circumstance. It does not. It holds true if and only if part of the table is in extraneous motion and the other parts move with it simultaneously. That is motion other than normal platter rotation. High mass tables are more likely to be immune to such motion.

**Reed used to make an armpod.
 
I believe Nandric (Nikola) had the first one ever made by Vidmantas. I was looking for the resonance research data that was prominently displayed on his website, which showed a visual of the different resonances and their paths (integrated versus isolated parts). The info had a lot of cool lines and colors differentiating the two, with information clearly supporting the armpod.**

Regards, 



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.
That is the most unlikely scenario. Airborne induced vibrations in the platter/tonearm/cartridge synergy are virtually non-existent as the turntable world would have ceased to exist if this were not so.
Err...anyone ever go to clubs with DJs playing vinyl at 105dB levels?
Structure-borne vibrations are by far the greatest source of distortions in the vinyl playback system. That is why the makers of anti-vibration stands (both active and passive) are successful. These stands have zero effect on air-borne vibrations.
Because the induced ’feedback’ is amplified when the volume is increased....most lay people conclude that the ’volume’ has caused the feedback when it is in fact the ’volume’ that simply amplifies the structure-borne feedback which already exists within the particular system.
Yes indeed...because Ralph can, with the same conviction that he demonstrates his turntable theories....can postulate that OTL valve amplification is the only true path to audio Nirvana....despite the observable distortions.
For the record, this is not entirely true. I do think OTLs have advantages, else I would not be making them. But all amplification has observable and audible distortions. A topic for another thread.

That’s a direct quote. Now we learn the motor is at the end of a long hose. Does it produce 90-95dB of noise in room? If so, is this noise + mechanical vibrations?

The measurements are based on this story and now it looks inappropriate. This is the same as the music coming off a turntable?

Looks like we have no relevant measurements.

The vacuum system, along with the monitors, produced about that much sound pressure at the time. There is no mechanical vibration from the vacuum system whatsoever- all the sound is airborne. So these measurements are quite relevant. Fleib, if I can offer a bit of advice, try to craft your posts in a way that it is not obvious that you are simply trying to make the other party wrong by ignoring facts. You will have greater success.
But the "correctness" and superiority of a common plinth turntable design does presume the plinth provides an inherently rigid mechanical connection between platter bearing and arm pillar simply by virtue of it being common, too large a presumption as well as an over-simplification, I realize in hindsight. The rigidity of the plinth in different tables varies, and is a major contributor to the sound of every table. Their designers have invested a lot of time, effort, and money into either maximizing the rigidity of the plinth, or at least strengthening the mechanical connection between platter bearing and arm pillar.
As I have maintained since the inception of this thread, the rigidity of the plinth is paramount. If the plinth is not rigid, then it can talk back to the pickup and editorialize. This is no better than an arm mounted on a separate pillar.

I think we can all agree that none of us are interested in what sucks. We want the best for our ears. So can we agree that in this conversation we are talking about the assault on the state of the art? If not, the conversation is moot. Please do not bring up inferior execution as an argument- such would be a logical fallacy known as a Strawman.
the front end of the arm. Free to vibrate (how much and at what frequencies dependent on the stiffness and resonant characteristics of the headshell, arm tube, all the way back to the arm’s bearings and counterweight, and down into the main pillar), it will and does! When the end of the arm, and therefore the cartridge, the measuring device of the LP groove, is free to vibrate and resonate (especially cartridges employing low-compliance stylus’), it is surely adding to or subtracting from the output of the cartridge. That is a major source of lost or added information in the playing of an LP, and only one table in the world addresses the issue. Now do you recognize the table?! ;-)
I don’t recognize the machine, but I recognize the flaw in the thinking of it in that way as you point out. The cartridge must be held in absolute locus- the arm can’t be talking back to it any more than the rest of the machine.
That is the most unlikely scenario. Airborne induced vibrations in the platter/tonearm/cartridge synergy are virtually non-existent as the turntable world would have ceased to exist if this were not so.

This statement is false, although I do agree that structural borne vibration is also a problem and have stated exactly that in prior posts. This comment suggests to me that you have not read them.

If you think air borne vibration is not a problem you are up against the issue of the real world. No matter how dead you think a thing might be, it will always have some motion, some vibration. Its inescapable, unless you subscribe to the idea that perfection is indeed possible in this world. When I went to engineering school and for that matter elementary school, my teachers were at pains to make the point that perfection is impossible - that is why we have the term ’state of the art’. It is this latter bit that underscores how your statement in quotes can’t possibly be true.

So a proper design must take into account that air borne vibration as well as structural borne vibration exist no matter how damped the setup.



**Fleib, if I can offer a bit of advice, try to craft your posts in a way that it is not obvious that you are simply trying to make the other party wrong by ignoring facts. You will have greater success.**

My posts were based on the information you supplied or didn't. How can I ignore facts which weren't offered?  You were repeatedly asked details about the pod. Did you give them?

Assuming your results are what you say, why should we accept this as the last word on this matter?  Prominent table/arm designers have reached different conclusions.  You're more knowledgeable than Kuzma, Reed, or Torqueo Audio?

Reed site had a set of resonance numbers which favored the pod. They're gone now, but your anecdotes are fact?

Atmasphere, you've made your point and I think everyone understands it. Why don't you go back to tube design or mastering? Unless we can figure out why results differ, there's nothing more to say.


My posts were based on the information you supplied or didn't. How can I ignore facts which weren't offered?

Trying to make someone wrong is a simple technique, which weve seen on the web countless times. In so doing, the goal is not mutual understanding but simply trying to make someone else wrong solely for the sake of doing so. It does not further knowledge. IOW I don't agree that your posts were based on what you say- as far as I can see, you want me to be wrong and go away, simply so you can be right.

I'm not here to make you wrong; someone asked a real question and I answered it with the accepted and correct engineering principle. It does not matter to me beyond that, others might disagree, but they are not wrong because **I** don't agree with them, they are wrong because they lack the engineering understanding:

Assuming your results are what you say, why should we accept this as the last word on this matter? Prominent table/arm designers have reached different conclusions. You're more knowledgeable than Kuzma, Reed, or Torqueo Audio?

Reed site had a set of resonance numbers which favored the pod. They're gone now, but your anecdotes are fact?


To the latter: of course, but to be clear they are not anecdotal if backed up with the measurements; of which so far I seem to be the only one here to have caused their hand to move to get (and I hope the irony of this conversation is not lost on anyone....).

To the former: apparently, if you are saying by being correct on this subject I'm more knowledgeable, but I'm not under the illusion that because I am correct about  this that I know more than someone else. What's happening is I understand the engineering, that's all.

I've been designing tube stuff and mastering all along- no need to go back, I'm already there. I know why the 'results differ'.

It does seem though that this rather odious bubble has been popped and its contents safely dispersed without harm to the parties in the vicinity.