Eminent Technology ET-2 Tonearm Owners

"you misunderstand how it works".

Not so.

Please reread my post.

I was referring specifically to the static effect - hold a magnet near apppropriate metal: does it have zero effect?

Of course much more important is what effect do these eddy currents have - must have negative effects. Has it ever been objectified ?

John,

The spindle's material is aluminum. It is not magnetic, in that it is not attracted by magnets, but it is affected by eddy currents. This video should help:

http://www.youtube.com/watch?v=H31K9qcmeMU

First an observation as I read what Ketchup and yourself said about the compliance in the air bearing spindle.

Ketchup do you notice any difference in force required to move the spindle in your ET 2.0 and ET 2.5 with no air on?
My ET 2.0 spindle can be forced through the manifold with no air. There is quite a bit of resistance but it can be done. This is normal according to Bruce. And its anodized coating prevents any damage.

My ET 2.5 spindle will not move – it is really tight. There is not much movement at all without air. It has to be really forced.

Chris,

The compliance that Richard and I were talking about was in the o-rings between the manifold and the manifold housing. No matter how much air pressure you can get between the manifold and the spindle (making it very rigid), you will always have the squishy o-rings causing the spindle and manifold to move within the manifold housing. Not rigid = not good, hence the shims. Most other linear tracking, air bearing tonearms don't have o-rings to soften up the bearing. I believe that getting rid of this compliance may have a huge effect on performance as Richard suggested. I WILL be doing this after I get my system set up and I'm familiar with the sound without the shims.

When I bought my ET-2.5 arm I actually did notice that it was a little difficult to move in the spindle with no air. I assumed that the spindle was out of round, but it worked fine with 1 psi in it when I did the air flow tests.

Looking back at my notes from the air flow tests, I observed dragging at 1 psi with the ET-2 (set up on a TT with the arm wand, cartridge, and counterweight) but did not experience dragging with the ET-2.5 at 1 psi. The ET-2.5 setup did not have an arm wand or counterweight attached, though, so it's apples to oranges. The dragging with the ET-2 was most likely due to the added weight of the arm wand, cart., and counterweight.

Also, I showed Bruce the results of my air flow tests and he said that both my ET-2 and ET-2.5 tonearms were set up for high pressure. I should have mentioned this earlier...

Thanks for your post. j