Eminent Technology ET-2 Tonearm Owners

Chris, thanks for Bruce's comments. It all makes complete sense, however my question is still not answered. I suppose its academic, but as a point of interest, I fail to see how air would NOT escape regardless of pressure. Air (like water) under any amount of pressue will choose the path of least resistance, so even though the air delivered at the "ideal" pressure will "surround the spindle 360 degrees", some air will still escape out of either end of the spindle; there is no gasket or blockage to stop it.

Re Dave's comment about air bearing stiffness: with my HP 2.0 bearing and Wisa pump, if I push on the spindle sideways, it takes very little force to cause the spindle to rub inside the manifold. With the Medo delivering 17-19 psi at the arm (yes, it will do that), it takes a considerable amount of sideways force to cause it to rub. The bearing is MUCH stiffer with the Medo, with a resulting major improvement in sound; particularly in the areas of dynamics, bass tautness and speed, and soundstage detail and stability.

Hi guys,

I talked with Bruce yesterday. My 2.0 HP manifold is two weeks off. There are no 2.5 manifolds nor setup jigs available right now, but there are tentative plans to make a production run of both in the next 6 months or so. Bruce confirmed that the 2.0 HP manifold is a better match for medium/high compliance cartridges and the 2.5 is a better match for low compliance carts (difference in horizontal effective mass with the 2.5 being heavier as noted previously in this thread).

We discussed the topic of air pressure and air escape. My interpretation of the conversation is that it is normal to be able to hear some amount of air escaping from the bearing and also to be able to hear a low-level air noise at high volume with your ear to the speaker (Chris's pump test). The amount of air escaping and thus the audibility will increase with higher air pressure for a given bearing clearance, consistent with my experience.

After extended listening comparisons, some including my golden eared wife, I have decided that changes in air pressure are audible (similar in scale to VTA changes) and our preference changed with the recording. Keep in mind that this is with the stock 2.0 manifold. Some instruments within the soundstage move forward at higher pressures, creating a better delineated front-to-back separation, but the overall sound is less relaxed and natural, with a change for the worse in tonal balance, particularly on piano. Ended up back at 3.6 psi (at the arm) for best overall performance with the stock manifold. Bruce has said this to me consistently over the years and, being the hard-head that I am, I had to prove it for myself and finally have the proper quality and control of the air system to feel confident in this conclusion.

As always, this is MY preference in MY system and YMMV. I feel certain that all this will change with the introduction of the HP manifold, where the smaller orifices and tighter bearing/spindle clearance will eliminate the downsides described above at higher pressures and further enhance dynamics, bass performance and soundstaging as Frogman describes.

Dave

from the Audiophile Club of Athens.
A very interesting website with a lot of audio passion like here at Audiogon.
I came across a recent visit with a member with an ET 2.5 on a Micro Seiki table.
He also has an SME V and ZETA tonearm on the same table.

To see the ET 2.5 in action for a bit, scroll to the bottom of the page for the video.

http://www.aca.gr/index/meetings?row=2320

to Kyriakos (owner of the ET 2.5)

If by chance you happen to visit Audiogon, please stop by and say Hi to us here !

Cheers

Chris, this pertains to an earlier discussion about identifying a 2 vs a 2.5. Look closely at the pictures of the ET. I would bet one of my extra arm wands :-) that its a 2 not a 2.5. The HP 2 is sometimes mistakenly referred to as a 2.5. Regards.