Eminent Technology ET-2 Tonearm Owners

Hi Thekong

Lead is also banned in Canada. Based on the shape and size of the ET2 counterweights here is an easy DIY alternative.

Go to any tire shop and pick up a couple of the lead weights that they use on wheel rims. They are of substantial size. They are easily snipped and the hole drilled to make any size weight you need. To get the nice square look as BT’s take them to a machine shop. Otherwise you could be up and running in the same day with the lead.

Nice speakers btw ! I am glad we have distance and a lot of water separating us otherwise I would be tempted to come over and ask to borrow them for a while.

Some more impressions.

The lead weight reminded me of something.

I “experimented” with a form of higher mass quite a while ago but only at the counterweight end. I had at the time email conversations with a couple of high profile Audigon members who were in this "lets add more weight to the counterweight camp” with their past experiences with the ET2 and ET 2.5. I really hope they see this post.

I added more weight to the counter weight end and tried to get as close to the spindle as I could. I found the sound seemed to get “bigger” each time I did it. It was addicting. I also did not have my Studer at the time for a reference point in my room for the sound. I made extra lead weights sourced from the tire shop I referenced above.

The horizontal mass of the arm may not have been seeing “some” of this extra weight as it was decoupled, but the air bearing spindle itself was. I talked to Bruce about this. Now lets imagine that he has heard every story you can probably think of in the last 20 + years from tweakers, hot rodders and experimenters of his tonearm. He was very clear to me. Try it and see...

So he encouraged me and said at some point I would affect the balance of the spindle, the air would not be able to sustain the spindle weight properly, and rumble would occur. something like that.

I never got as far as actual rumble occurring and then the light came on for me. The ET2 counterweight ” I” Beam is the most misunderstood part of this tonearm and the EASIEST to screw up. The ET2 arm comes with a set of lead weights along with a range described in the manual of the minimum and maximum cartridge weight they can counter. This range can be modified btw - but thats another discussion. How many of you have thought to yourselves, I don’t want to lose them. So lets put them all on the counterweight. Who hasn’t done this when you first started out with the ET2 ?

How many have even done it with a light MM cartridge?

NOW the really big question - imo.

How many Michael Fremer types (professional reviewers) have done the above - used all the weights when they were not needed ?

Has anyone ever read an ET2 review where a description of the weights (how many used/positioning on the I beam was actually described.

There positioning is as critical to the sound as the fine tuning adjustments made to the cartridge itself. Very sensitive. Without the knowledge about this ..

Well as noted in the previous posts from Dover the manual doesn’t say add extra weights like I was doing in the experiment. It says it is preferable to get as far out on the beam as you can. This implies less weight on the I beam itself as its intent is to be decoupled. Think about it – the weight is on a leaf spring. ITS A HORIZONTAL VERSION OF A CAR/TRUCK LEAF SPRING . Get that in your head and your home free with this tonearm – IMO.

So this Iight came on for me around the first couple of pages on this thread. Someone that calls himself Frogman reminded me.

Btw – I thought this person that calls himself Frogman was a scientist that spent his time where its wet; looking for Frogs. Monikers being what they are. Boy was I wrong !

Re-applying less weight further out on the beam; the tuneful bottom end returned with more speed and coherence. Similar wording to one of Dovers previous posts.

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Warning - The above post about adding "mass to the counterweight" does not relate to the mass spindle dampening being discussed. Persons reading this thread do so at their own risk.
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Chris/Frogman -
Thanks for your feedback and comments. I was beginning tho think that analogue heaven consisted of only me and Bruce on a desert island.

I think the key point Chris as you have alluded to is that even if we assumed the Kuzma was the best arm in the world, adding substantive mass to the ET2 is wrong, it is taking it out of its design parameters. To accommodate the mass one would have to redesign the main air bearing and retune the Q of the total system. These factors are being completely ignored by the other folk.

Chris I note that you are also using the carbon fiber arm tube for high compliance cartridges and yet still finding the optimum is only 2 springs with the Benz. This does suggest to err on the more decoupled side of the ledger for LOMC's as well, the only downsides being possibly a fall off below 30hz.
I would be very surprised if many were getting below 30hz in a domestic environment, and if they were it would be unable to be controlled in that environment. To put it another way a roll off below 30hz I would see as an advantage in most domestic environments where room bass response is usually quite uneven and unpredictable.

Further to the above post for those interested the weights of the arm options excluding the wire are: 13g ( Al) . 17g (Cf) & 19g for the heavy magnesium version. So Bruce has designed in only an additional 2-6g for MC's.

03-13-13: Ct0517
The Rockport and Kuzma tubing makes me think of my past experiences with my VPI JMW 12 tonearm. That tonearm’s wires are used as its antiskating method. Their positioning pushes the tonearm back toward the outside.

Could the tubing being in a loop at the centre of the Rockport and Kuzma arm, be acting as a type of dampener for the arms motion in both directions ?

03-18-13 John47
Mr Kuzma replies to MF

[quote]"A question of damping..."
........ There is, in fact, a level of effective damping on the Air Line tonearm. The cantilever suspension, and the air supply tube add damping. Our choice was for either too little or adequate damping; we chose the latter.

John47 - Thanks for confirming my assumptions with the Kuzma.

Dover - My ET 2.5 has the CF armtube and was the one I referenced in my post with the Benz Micro. So many variables here. Plus the specs I listed are for the stock cartridge – it is now a Ruby cantilever SS retip. I have no idea if the specs were changed when it got retipped. Does anyone know what a Ruby cantilever does over the stock Benz Micro one ? The cartridge came with the VPI TNT I bought years ago, and it needed a retip when I purchased it so I never heard it in stock form.

Richard – the triple leaf spring is tight but not 100% tight. It has a tiny bit of flex in it but you need to force it a little. If you hold it by the I Beam and shake it - it doesn't move. Still it is not as stiff as if you stuffed two toothpicks on either side.

Cheers

Re quality factor, Q. ... under, critically or overdamped systems, as they relate to the ET2. My running the arm at 12 psi is no accident. I addressed the Q factor of my arm years ago. And the bearing has no issues at all carrying the extra weight, even at this pressure.

I don't have any proof of this, it is just a recent thought. While higher or lower weight is obviously a factor, I think that the one leaf spring, two leaf spring plus number of weights thing, has probably a whole different set of cause and effect issues. So with reference to a rigid or sprung counterweight beam, it is probably an all or nothing event. In other words because we have the "potential" interaction of the swing frequency of the beam and the resonant frequency of the arm assembly, depending on the number of leaves and the number of lead weights used. It could be that tuning here with springs and weights (and their position) is at least partly to do with sorting this possible frequency interaction rather than just the weight or stiffness employed. Others may have already thought of this but, it is just an idea to put out there for comment.