Linear Tracking Turntables - Best??


Entertaining the idea of acquiring a linear tracking turntable. Which was condidered the most sota. Ease of set up and maintenace is a prerequsite. Most I have talked with,say linear only way to go. OK AUDIOGON MEMBERS ITS YOUR TURN. Convince me one way or the other
ferrari
Donc55 that's why the only ones I would use are the air bearing ones.
Atmasphere the ET2 can be set with the bearing at the level of the LP.
The ET is also stupidly well priced for what it is.  SOTA for under 1K used.  I think it's because a lot of people are afraid of it. And no it does not require constant adjustment. Once set it stays that way.
The ET does indeed have the bearing at the right plane. The problem is the lateral tracking mass. Lightening up the arm would likely help but the real place to lighten things up is in the bearing itself. Have there been any carbon fiber air bearings? I'm not aware of one, but if such were produced, it would be a simple method of reducing this issue considerably!

The fact that additional air pressure and a larger tank makes an air bearing sound better should tell you something. The engineering principle involved here is that the cartridge has to be held in perfect locus relative to the LP surface while still being able to move freely. To that end, there can be no slop in the platter bearings and the plinth must be absolutely rigid and dead such that the base of the arm moves in the same plane as the LP surface should there be vibration. The bearings of the arm must have no slop such that the arm is rigidly coupled to its base. Any difference between the locus of the cartridge and the surface of the LP will be interpreted as a coloration.

It is that latter part where the issue lies. Because there is slop is why increasing the pressure and adding a tank improves the sound. Essentially it reduces the effect of the slop. But the slop can't be eliminated entirely else the bearing would not work. Now we are talking about microscopic tolerances, but grooves on an LP are microscopic too.  The only way around this is not not have slop which is impossible with an air-bearing arm.

Now I'm not saying an air bearing arm does not work- Bruce could not have stayed in business over 25 years if the arm didn't work! What I **am** describing though is the envelope that needs to be pushed.
Atmasphere

All ET 2.0 and 2.5's are designed to work at a certain PSI.  Bruce tailored them to customer specs and he also offered lower and higher pressure models. They need to be run at the PSI as designed.
Now The problem. 

Many owners especially those in high humidity areas not using a water trap, have let moisture carrying minerals and other crap into the manifold allowing the capillaries to get partially clogged. This is when higher psi does indeed help a bit forcing more air through the manifold and the capillaries/partially clogged. Owners wrongly assume it sounds better because of higher PSI.   But its a band aid.  The fix - clean out the holes! .....and use at the designed PSI.

Many buy used ET2's and have never cleaned out the capillaries as shown in the manual.  They have never ever  taken them apart; and they have no idea what PSI they were designed for - like an ebay sale. We have discussed the procedure for how to determine the PSI that Bruce designed them for on the ET2 thread.

So one needs to filter out (pun not intended) and qualify what you read on the internet. The design also has a 19 psi limit -  if set up this way by Bruce in the first place. Like my 2.5. So if you read about someone using i.e  28 psi .......:^)   be leery.

Air Quality vs Air Volume Higher PSI. 
Don't confuse higher psi volume of air over the quality of the air delivery that is being delivered. If the ET 2.0  2.5 is operating properly it is the quality of air delivery from a better pump - not the higher psi that improves its sonics. This is proven by using two pumps, same psi differing in air flow quality only.

The ET2 tonearm more than any that I have owned or am aware of allows, invites mods.The envelope can be pushed as far as you want to go. But, first, you need to figure out how it works.  This takes time and patience and out of the box thinking since it is unique.  


If the ET 2 is run properly  there is no slop in the bearing as far as in and out. Not with the usual forces that the cartridge puts on it. 
The air bearing "slop" issue has to do with not having physical contact between the arm and the structure of the rest of the table (arm base and plinth).  Micro vibrations caused by the stylus tracing the groove don't have as effective a path to be dissipated elsewhere so the arm itself tends to shake.  That energy can be damped and reduced by a "stiffer" air bearing, but, this is just one of the challenges of designing air bearing arms.  

As for the mass issue, it is not just that these arms tend to have higher effective horizontal mass, it is also the case that the stylus/cantilever has to drag the whole arm from the force applied to the end of the arm without the mechanical advantage that pivoted arms have (pivoted arms are effectively levers).  My other issue with most of these arms has to do with their shortness.  The shorter arm has certain advantages (lower vertical mass, greater rigidity), but it also means greater changes in VTA from different thicknesses of records; both of my cartridges are pretty sensitive to small changes in VTA and I am not someone inclined to fiddle with adjustments for each record.

Whether or not the inherent mechanical challenges of such arms outweigh the advantages, is, I suppose, a matter of debate.  I do know that I have heard some pretty nice sound from systems using air bearings like the ET 2, Walker, Kuzma and a few others.  I even liked the sound of my cheapie Mapenoll but I got rid of it because of the issue of the cheap air pump not delivering enough pressure.  But, I have also heard terrific pivoted arms of all sorts, so I am not convinced of the inherent superiority of any particular design.
@ct0517 , Thanks for your explanation- I bet there are a lot of owners that don't check that!