Eminent Technology ET-2 Tonearm Owners

Richardkrebs- There is nothing particularly unique about the ET2 bearing.

Richard – what is this statement based on?

Please note this observation from Thekong who has compared it to the Rockport.

03-13-13: Thekong

Hi Ct,

However, there is one interesting point that I still can’t understand. When moving the arm in and out by hand, the feeling of the ET is smoother (or I should say requires less force) than the Rockport! While I don't have the spec. of the 2 bearings, I have always assumed that the Rockport has a tighter tolerance / air gap. This can be shown when trying to move the arms without the air supply. While you can still move the ET quite easily, a lot more force is required for the Rockport in this condition.

If the air is off on my Kuzma Airline it is quite hard to move the tonearm.
Will be joining the ET owners club.
The ET arm that I purchased should be in my sweaty hands by the end of the week.

Chris
The statement about the ET2 bearing was in relation to it being subject to the same rules regarding resonance , load carrying capability dynamic stiffness etc.
Any problems due to higher mass will manifest themselves in linear air bearing designs regardless of the manufacturer. There may be variations in degree, but they will be there.
In other words if my heavy ET has problems with cantilever flex, bass boost, phase shift and so on; so do the other heavy arms. Rockport, Walker, Kuzma. This because the horizontal effective mass is solely determined by the total weight that is moved sideways at the frequency of interest, since all of these designs are virtually frictionless.
The level of damping of course changes all this. Enter the oil trough.

The difference observed between the ET2 and the Rockport could be due to the designed operating pressure and the bearing clearance. Haven't seen a Rockport in person so this is a guess.

Hi Rugyboogie,
Can the moving assembly on the Airline be taken out easily? If it can, and it is not too much trouble, I would really appreciate if you could weight it to confirm whether it is really only around 100g.

Hi Ct,
Yes, I still don't understand why the ET bearing feels smoother (to the hand) as compared to the Rockport when both are having the air-supply. I would assume both of them are virtually friction free under this condition! Maybe Rugyboogie can share with us his finding when he got his ET!

Oh, it just dawn on me, could the "less smooth" of the Rockport bearing cause by the flex of tiny airhost? If it is, then the airhost actually provide considerable "damping"!