Eminent Technology ET-2 Tonearm Owners

The base of the ET2 is mounted with one bolt and has 3 grub screw spikes for proper leveling on any surface or armboard.
We have discussed removing the aluminium shim. If your worried about marring your surface, Dover had mentioned filing down the grub screw points.

Can the bracket be improved or .......removed...? Another material? It is the part that holds all of the goods.

Cheers

Can you please advise (and of course fellow posters) what speakers you were using in your system when you set up the loose counterweight decoupling method.

I am interested in this approach and its effect on the sound, particularly in the bass region. Thank you.

For clarity: the question in my last post was addressed to Mr Dover.

I have been researching possible bearings for a new Arm and I came across the Kuzma web site and the Airline Arm. This appears to be unique in using a porous material rather than multiple drilled holes like the ET. It also has a sliding sleeve instead of the sliding spindle of the ET

Wow this is a spectacular looking arm which is definately on my wish list.

This brings me to the subject of horizontal effective mass again. I asked them for this figure for the Airline. It is probably not appropriate for me to publish this here, since it was a private conversation and the number is not shown in their specs. But I can say that it is higher than my heavy modified ET2 arm. We went on to talk about potential problems with cantiliver flex. His response was the resonant frequency due to the combination of a typical low compliance cartridge and horizontal effective mass was in the region of 2.5 -3.5 hz.(this has been published by them elsewhere), this is well above the 0.55 or 0.75 hz for 33 or 45 rpm eccentric records. Therefore the cartridge does not "see" this movement.

He directed me to a video of the arm and cartridge tracking the lead out grooves with a oscillation amplitude of 12mm. See www.Kuzma.si ,tech support,tech info, Airline video.

This Video was posted by them to allay fears of cartridge damage due to high horizontal mass.

This arm is amongst the best currently available. It has a large differential between its vert and horizontal effective mass figures and does not appear to be a cartridge killer.

I'm sure you will agree that this motion is violent and way beyond what any record eccentricity would produce. He assures me that there is no problem with the cantilever under these extreme circumstances.

I want one.

Richardkrebs

I have queries regarding your claims re the Kuzma air bearing tonearm.

This appears to be unique in using a porous material rather than multiple drilled holes like the ET.

This is not correct. The ET has a captured air bearing with a continuous air gap between bearing spindle and manifold.

We went on to talk about potential problems with cantiliver flex. His response was the resonant frequency due to the combination of a typical low compliance cartridge and horizontal effective mass was in the region of 2.5 -3.5 hz.(this has been published by them elsewhere), this is well above the 0.55 or 0.75 hz for 33 or 45 rpm eccentric records. Therefore the cartridge does not "see" this movement.

This defies basic physics.
Any lateral force on the stylus forces the cantilever to flex laterally, until the resistance of the cantilever to movement meets or exceeds that of the arm, at which point the arm must follow.
More mass in the arm = more inertia in the arm = more flex in the cantilever.

This Video was posted by them to allay fears of cartridge damage due to high horizontal mass.

This arm is amongst the best currently available. It has a large differential between its vert and horizontal effective mass figures and does not appear to be a cartridge killer.

The video does not show the cantilever. Proof of the above assertions is not demonstrated.

As regards the best available, what other arms have you auditioned to draw this conclusion.
If you are talking air bearing arms - where have you considered the dynamic stiffness of the air bearing. Although the Kuzma runs 60psi into porous tube versus the ET2 at 19psi into captured air bearing, the psi alone does not determine the dynamic stiffness.

Some other factors you need to consider are :
The hole sizes
The flow of air
The surface area of the bearing
etc

The ET2 also has a wider manifold. If we assume for arguments sake the air bearings are of equal dynamic stiffness, the ET2 will be inherently more stable than the Kuzma.

He assures me that there is no problem with the cantilever under these extreme circumstances.

This is an inadequate response.

To support your contention that adding mass has no deleterious effect, which cartridge designers have you sought an opinion as to loading up the cantilever in the manner you continue to advocate in this thread ?

Bruce Thigpen's patents clearly outline the benefits of the decoupled counterweight and lower mass.