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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
thekong
203 posts
 

Hi Halco,


While I tend to agree with Ralph /  atmasphere, I think it would be interesting if you could do some tests.


To my way of thinking, the test can be rather simple, just lower the cartridge on a stationary platter / LP, then play music through the CD system, and measure the output of the cartridge.


If Ralph is right, then there should be more signal / noise with the stand alone arm pod. With this test, you can even see how high the volume needs to be before the stand alone arm pod is affected, if at all. Actually, if we only need to know the level of output of the cartridge, would a simple voltmeter be sufficient ?


Anyone see anything wrong with this simple test ?

fleib
1,124 posts
 

Thekong's suggestion brings up an issue we haven't addressed. What exactly is the source of this vibration, and what is its relevance?

Atmasphere, you talked about a motor producing 90 - 95dB of noise in the room and described the vibrations as room borne not air borne. This sounds more like a seismic event than music playing, as if a bus or truck drove down your street and shook the house. We not only have 90+dB of noise, we also have the motor vibrations which produced the noise.

If you consider the principle involved, that is any extraneous arm/platter movement must coincide, then why is using a plinth more desirable than a base?  The best plinths are those that do not transmit vibrations, but now we want transmission?

I think the answer is in the execution. A "properly" constructed pod will not allow movement in a different plane. The base will serve the same function as a plinth only with more affective isolation. A seismic event is shaking the entire table and platform and your set up was unstable with the pod.

Regards,

ct0517's avatar
ct0517
2,041 posts
 
Copernican, Copernican, wherefore art thou Copernican ?
 
Ground hog day come late in 2016 ...
those familiar with that thread know what I am talking about.  

But with some changes this time around - more direct experiences. 
I sometimes wonder why people are on these forums. Do you guys ever think about it ? For me it makes my morning coffee time more interesting and takes my mind off of bad investments. Did you know the chunks of brass from the billets, that I bought for my pillars years ago have gone up in value......... a lot. Who knew..... 

Now I can understand for folks like Atma Sphere who are in the audio business, that the forums represent a way of promoting their products when they state their opinions. And since the OP Pani has already made his decision......I figured lets have some fun. You guys know I like visuals. Visuals are international regardless of the language spoken.   

So up first.
Here you have not the amps and preamps, but the Belt drive Atma-Sphere turntable and Tri-Planar tonearm, that Atma-Sphere (Ralph) speaks about in this thread.

http://www.atma-sphere.com/Products/Atma-208#

I was not aware of this product offering btw. I don't get around much these days.  
 

Another interesting find.  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.  Visual theory at its finest. 

Well guess what. The research data is gone, as is the armpod, as a product offering from Reed from what I can tell.

And now Reed sells a full integrated turntable.

http://www.reed.lt/components/com_virtuemart/shop_image/product/DSC_9267_hi.jpg

So a business move ....or something else ?

Hmmm......the search for Reed armpod also revealed an expired audiogon ad for someone selling his Reed armpod ................ :^)

***************************************************

Halcro (Henry)

You keep focusing on the pods themselves....

I am not reading into Atmaspheres' comments as you are. or maybe I am reading into his comments wrong, in which case let him correct me. After all Canadians speak a different language from those in the USA, eh ? Misunderstandings can happen.  
 
What I am understanding is based on his direct experiences with metallic bearing turntables and tonearms - in this case an original but modded Empire turntable, and Triplanar tonearm; he has concluded there is bearing movement (outside of normal movement) in both of them - this being the bearing structure itself of the platter system and tonearm. And therefore to put them to stand independently is a bad thing. So in this regard showing a picture of the pillar/armpod is not necessary as it is what is on the pillar/armpod itself - the tonearm and its bearing structure - that is the problem. AtmaSphere (Ralph) if I am wrong about this please correct me and good luck on your lathe project.

A gimbal design uses separate closed-cage bearings to allow lateral and vertical movement

while unipivots sit the tonearm on the point of a needle, allowing free movement in all directions

Maybe a discussion of the movements and therefore resonances of these types of bearing types would shed more light, as it relates to the pillar / armpod. What do you guys think ? 

fwiw - I don' t use metal bearings in my main turntable and tonearm. If anyone here reading has direct extended experience in their own rooms with magnetic platter bearings, and captured air bearing tonearms; I would be happy to share info. with you here or elsewhere.

Cheers
thekong
203 posts
 
Hi Fleib,

In his last post, 1st paragraph, Ralph clearly stated that the vibration is likely to be airborne.

Also, if I have read it correctly, Ralph's arm pod was on an antivibration platform together with the lathe, so I would assume most of the structure borne vibration had been filtered.

Ralph, please correct me if my understanding is wrong.
fleib
1,124 posts
 

Thekong, The original statement: **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.**

I suspect it doesn't matter. This seems to be more than sound pressure waves hitting the table, and we might as well be talking about table mounting in general. Why is a plinth superior in maintaining identical movement between arm and platter?  Either proximity, or lack of rigidity in table or pod coupling to the base.

We now know of at least a couple of prominent designers who have used the pod approach with "superior" results. No offense Ralph, but your expertise is with tubes and modifying an old Empire table does not qualify you as a table or arm designer.  I've modified tables and mounted arms, but I don't consider myself .......

Regards,

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