Eminent Technology ET-2 Tonearm Owners

Chris.

No I have not measured these forces and would be very interested to read Bruce's comments on same. I assume it is a big file, so can I ask you to email it to me at the contact address on my web page, if not too much trouble. Or if appropriate post it here.

As per my earlier post, both an oil trough and a magnet impose a resistance to lateral movement as seen by the cantilever. They behave much like weight in the lateral plane. I have simply used weight alone.

I did my initial tests on extra horozontal mass by disabelling the leaf springs on the counterweight beam and winding equal lengths of solder around the goose neck and counterweight assembly. This way I kept the lateral balance of the arm static. It didn't look pretty but was informative. I also tried this configuration with and without magnets.

I currently adjust for different cartridge compliances by using a range of counterweights.

Dover, I seem to remember from this thread or another that you no longer use an ET2. If so, we would be intereted in what you are currently using and any reasons for the change. As we all, I think, agree, the ET2 is pretty darn hard to beat.

Hi Richard – email sent.

Where are my manners ? Do you want to try the 420str cartridge?

Your table and arm would need to be set up for the higher compliance.

I was all ready to send it to NZ anyway.

When you are done you can maybe pass it to Dover? I think Dover misplaced his ET2 - and I think it may have something to do with a drink called Slivovitz from Serbia. Maybe Nandric (Nikola) can provide more details on this.

Hopefully Dover gets it back soon
Glad you guys on the other end of the world have a sense of humor.

Cheers Chris

Chris.
Thanks for the offer but I must respectifully decline. I am just dialing in my Shelter and newly renovated enlarged room. More distractions, while delightful, are unfortunately just too much for now.
re my building a new arm. The design would allow for bolting to a flat surface with three screws. Simalar to the ET. It has fully adjustable horizontal mass independant of the counterweight. I am struggling with the wand design at present, which is a little radical. While I can visualise it, I'm not sure I can build it. The whole project may founder on this. If I am to build a new arm, I want to be pretty sure it will be a step up from the present version.

Dover, what did you do, loose your ET2 in a drunken poker game or something?

Chris/Richard

As per my earlier post, both an oil trough and a magnet impose a resistance to lateral movement as seen by the cantilever. They behave much like weight in the lateral plane. I have simply used weight alone.

This is incorrect. This is like comparing apples, oranges and pears.
Magnetic dampening will vary with the speed of horizontal motion whereas the added mass approach is simply increasing static inertia considerably. The resultant behavior from an additional horizontal force will be quite different. Same for fluid dampening.
In terms of sound - with magnetic dampening I have gotten increased cartridge output, which indicates that the cartridge is losing less energy due to micro vibrations being damped. By contrast with all fluid dampening I hear a loss of speed, focus and detail. Dynavector also concur with this view in their discussion of their tonearm design. Despite the high horizontal mass they use eddy current dampening to reduce micro vibrations.

In my view the ET2 is the best arm I've used. I changed to a Naim Aro due to problems with a sprung floor and growing tired of pumps, tanks and airhoses running through the house. The ET2 is out on loan, but at some stage it will come back. In engineering terms a unipivot is the most rigid bearing you can get. I chose the Aro because compared to the Graham of the day it had no arm tube dampening, the Graham arm tube was full of crap, and the bearing was the correct way up for energy dissipation to ground ( the Graham had what I call an upside down bearing, point up ). The sound of the Naim Aro is quick, lucid through the mids, excellent soundstage and very musical. The downside is that I believe it has a very narrow operating window in terms of cartridge compliance and mass. The Dynavector Nova 13D sounds excellent as does a Denon 103D. The Koetsu Black sounds awful, unstable in the bottom end. I recently purchased an FR64S to try with my Ikeda Kiwame - this arm is one of the best pivoted arms I have used and due to the detachable headshell I am currently running this so that I can play around with all my cartirdges - Ikeda Kiwame, Dynavector Nova 13D ( freshly rebuilt from the ground up by Dynavector Japan ), Koetsu Black and Denon 103D.
No pivoted arm in my experience can match the transparency and presentation of the soundstage as well as the ET2 though. Furthermore as you will be aware, there is plenty of bottom end depth and speed if set up properly, despite reports to the contrary.

Dover, can you clarify a few points concerning the effective horizontal mass of ET? The manual states that it is 25-35gms. Is this the mass of the wand plus manifold tube, which is then increased by addition of up to 40gms in counterweights?

I understand that the mass of hanging decoupled counterweights behaves differently than fixed counterweights. It would be interesting to have the math on this horizontal pendulum effect. In any case, while the design may lower horizontal inertia to an extent, it will also contribute to horizontal inertia to an extent. I would imagine that the effective horizontal mass of the entire moving system is quite a bit higher than 35gm.

In the course of developing the predecessor of the Trans-Fi tonearm, Poul Ladegaard experimented with a pendulum counterweight. For whatever reason that feature was abandoned.

BTW, with a custom lightened CF slider and wand the horizontal mass of my Terminator totals 35gm. This includes custom front and rear wand counterweights designed to vary the wand's vertical effective mass. On my full-range system with a sub to 18Hz, the lighter horizontal assembly sounds better than the heavy one. Also, variations in vertical effective mass are more impactful than relatively large variations in horizontal mass.

Lots of variables.