A Copernican View of the Turntable System

Dear Geoch – I am trying to understand the benefit or reason for using the Rollerblock Jr.

Based on what Dgob is saying and the fact the Rollerblock use bearings how much weight are we really talking about when you say “really heavy loaded”.

I ask because I have two 2 ET tonearms. If there is one thing I have learned about that air bearing - is that it is very sensitive. It is set at 19 psi and it needs to be totally rigid and parallel once set and not move or it will introduce coloration, and distortion that is audible.

But I also think that this would apply to other "pivot" arms as well - any movement at all is not good ?

The "JR" has some advantages over the more expensive std Rollerblocks :
They have 1.86" disc plates on both! levels that are both! threaded at the outer side and are also both! curved inward. So, we can permanently fix them in the desired place at the upper level (armpod) and at the lower level (shelf). The disc plates are shelf centered with great precision by gravity as long as the shelf is allready dead leveled on horizontal plane. The 1.86" threaded disc plates can provide further leveling adjustment and their contribution is admirable in contrast to spikes/thin discs. The movements by accident are terrifying indeed, but in normal careful use, the great mass of the armpod impedes any disposition and restrains it to a soft activity. The remaining faint movement is progressively die out very quickly before the cartridge touch the LP. Of course it is a matter of the end user to value the pros & cons of this option, but the disadvantage of the careful operation & handling is an accustomed practice anyway to the parallel tracker's user. If you have a friend by which can borrow a set of 3 Rollerblock JR and see if you can manage to handle their lateral movement, it is definitely worth a try.

..."in normal careful use, the great mass of the armpod impedes any disposition and restrains it to a soft activity." Geoch, that is beautiful English, worthy of an erudite 19th century scientific journal entry. But what is "soft activity"? Any activity, if activity means movement or motion, is a bad thing if the platter does not move precisely in concert.

Dear Lewm, sorry about my English it is obvious that I'm using the dictionary mercilessly. This is what I meant :
The forces created by the cartridge and the tonearm during play, cannot cause any motion to the armpod, as they are received & collected like resonances & not like forces that can cause a displacement.
When we push accidentally an armpod that uses spikes as footers, the disposition even if it is slight, it is also permanent. When the footers in use are these Rollerblocks JR, the displacement of the armpod is quickly self-corrected and the whole moving mass is coming back again to it's exact position by smooth & progressively reduced circular move.
This activity is taking place from the moment that we release the arm lift and continues decreasingly so, as the arm tube is falling to LP. But it comes to an end before the cartridge reach the vinyl surface. Any further remaining activity that left, are only the resonances that caused by the usual suspects during the listening session & not by the Rollerblock JR which is way more gifted than spikes in draining these resonances.

Dear Lew, you are very difficult to satisfy or please. Even
the 'soft activity' is refused on theoretical grounds alone despite this saying about the pudding. Only the argument is changed from 'galleons' to a movement in concert with the platter. As I suggested (03-20-11) in relation to an brass cylinder you will be able to afford
the most exotic 'spikes' imaginable and those Rollerblocks
JR look to me very appealing. You can eventualy also use them to 'soft absorber' those tube amps of yours.
Regards,