Eminent Technology ET-2 Tonearm Owners

The Kuzma is unusual in its choice of bearing construction………… the use of porous material appears to be unique?

In his review on the Kuzma Airline, Michael Fremer also mentioned that the Airline use porous material in the airbearing, while the older, but similar designed, Rockport 6000 utilized a groove-compensated bearing, which has lateral grooves in the bearing wall.

He went on to comment that due to the difference in the bearing design, the much higher air-pressure used in the Airline didn’t necessary mean its bearing was stiffer.

It is also interesting to note that the arm on the Walker Proscenium turntable shares a similar design with the ET2, but using a fixed counterweight and much higher pressure at 45psi.

I believe Lloyd Walker is well known as a fanatic tweaker, who would not stop to squeeze out the last bit of performance from his turntable. So, why would he not use the decouple counterweight design (if he sees any advantage in it), or is that patented by ET?

Thekong
I don't know how long patents last, but would suggest the reason that Lloyd does not decouple the counterweight is simple.

It sounds better.

It sounds better

Hi Richard, I am no engineer, so has absolute no idea about the physics behind it. However, as Lloyd didn't use the decoupled counterweight (which is not hard nor costly to implement), I also believe it probably sounds better that way, at least to his, and apparently also to your, ears.

Actually, I have also fabricated a fixed counterweight for my ET2.5, but unfortunately have no time to test it yet. When it happens, the ET would be compared to my favorite arm, the Rockport 6000!

Thekong

We look forward to reading your comments.

Richardkrebs
Referring to your last post 03-12-13: responding to Dover.

At frequencies below resonance the cantilever is free to push the mass of the arm sideways. This does not defy physics, it is physics.

Correct

In other words the cartridge suspension is stiff enough to accelerate the arm mass sideways. .

That is an assumption that will depend on the compliance of the cartridge. If the compliance is low enough then possibly, but before the acceleration commences the cantilever will flex.
You seem to be unaware that cantilevers are mounted in a rubber elastomer that is not rigid.

Think of a tension spring with a weight suspended at one end. This combination will have a resonant frequency. If you hold the spring end opposite to the weight and move it up and down at a frequency below resonance the weight will move up and down in sync with your movement. The spring will NOT stretch as a result of this movememt. .

A curious analogy, yet again, you compare apples and oranges.

Your analogy compares
1. Holding the end of a spring with a fixed weight on the other end
to
2. The stylus point sitting in a groove, not held, at the end of a cantilevered beam, at the other end of which is a rubber suspension ( not a spring ), and the other side of the suspension has a mass loading that is constrained at 90 degrees by the rigid air bearing some 6 inches away.

Your analogy is a triumph of the imagination to consider these two scenarios in the same manner. Your discourse on resonant frequency is irrelevant.

Quite frankly I cant be bothered doing the maths, but I defy anyone to show me a cantilever that does not flex when playing an eccentric record. This does indeed defy physics unless you have a cantilever that has zero compliance.

No, the video does not show the cantilever, that is why I asked him if it was a problem.

If you agree the video does not show the cantilever then why do you repeat the following statement that is misleading?

I repeat the video is shown specifically to allay fears of problems due to high horizontal mass. .

I assume from your lack of response that you have not sought any advice on this matter from any cartridge designers. I would have thought this was the first port of call for a thorough and complete understanding of the problems of navigating eccentric records.