VPI 2nd Pivot for 3D

Dear @moonglum : Achilees heel in fixed/gimball tonearm bearing designs?

Well, as in any tonearm design all depends on the design it self and the quality excecution level of that design.

In the fixed tonearm bearing design there is no inherent achilees heel as in all true unipivots. Gimball type tonearm bearing designs can comes with " mistakes "/bad design in that regards but what is happening down there and that you explain in wide way ( brinelling. ) is not inherent to those kind of design.

You can take for an example a vintage tonearm design as Technics where the designers decided to use four bearing points and use at each bearing points 5 ruby balls ( 20 in total. ) with a roundness tolerance of 0.5u that permits a bearing friction number ( in all directions. ) of less than 5mg. and it´s not only that but all the care Technics took for its production. A superlative product that even today is the " envy " for any tonearm manufacturer.
Brinelling there is almost non-existent. Of course that there are truly bad designs as the FR tonearms that in that regards is one of the worst examples you can find out but even this those stylus tip/groove huge forces makes that the tonearm moves!.

In the other side, the very tigth tolerances on today gimballed designs makes that you don’t have to worry about. In the past almost no one use ABEC 9 balls and today is a must and almost every one use it at the tonearm bearings.

Everything the same unipivots are in total disadvantage against giball/fixed bearing tonearms.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Is the addition of the second pivot restricted to the 3D arms and if not should the effect be of equal value?

Hi Raul,

Thanks for your thoughts on the widespread use of ABEC9. Of great  interest is the fact that that there are buyers who wish to supersede the Technics tonearm (excellent quality) on the new SL1200 with {insert as applicable} tonearm? Vandalism! :)

Sometimes, with gimballed, it came down to bearing quality and alignment. (Remember the Breuer arm?)

http://www.adventuresinhifiaudio.com/03/12/2013/the-breuer-dynamic-type-5a-pickup-arm/

Moving on, it’s very common to see Forum questions such as, “Is Product A Better Than Product B?”.

On this thread I’ve argued both merits and demerits of both sets of products/methods. Examples of the above question could include “Is MM Better Than MC?” or “Is Direct Drive Better Than Belt Drive?” or “Should MCs Be Damped or Undamped?”. In each case there is no outright winner or global resolution, much though everyone would appreciate that to be the case. Life would be simple if it were.

I can understand that those engaged in the above topics sometimes misguidedly expect a “winner”, as indeed they might do in this thread, but as you have seen in the past it is not happening. The result is what we politely and affectionately refer to as “debate”. ;^)

 

Gimballed tonearms have been in manufacture a long time to the extent that they might be seen as the truer “soft option”.

To me, folk suggesting unipivot design/manufacture is “easier” than gimballed is rather like saying that designing a pushbike is harder than designing a gimballed tonearm because the pushbike has both gimballed bearings and gears(!) ;^)

It’s meaningless because those concerned are trying to find their own unique solution to a set of design problems.

In fact, many manufacturers will sub-contract the bearing design and manufacture to an agency (Japanese companies are historically good at this, as you indicated) after which it becomes an item on an assembly “tick list”.

Who needs to pre-load and align bearings when you can get someone better at it to do it for you? (to balance things up, Unipivot bearing manufacturers can also get help if they need it.)

 

Being a Devil’s Advocate is hard work.  ;^)

Best regards,

Bill

@tooblue  answers are No and Yes, respectively.  

Pardon me if I have missed this in the previous post but is the second pivot an option on the metal arms as well as the 3D arms and if so would the benefits as heard by some be the same.