Eminent Technology ET-2 Tonearm Owners

Hi Frogman - both my I-Beams have a single spring in them.
Thank you for the wire info Daniel.
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I havent figured out how to convert a bitmap to text. Need to download some program. Quicker to type it out :^(
Adjusting the Arms Mass.
From the manual page 9

Adjustable effective mass

The effective mass of the tonearm is adjustable both vertically and horizontally. The arm has low-medium mass vertically and medium to high mass horizontally. Four counterweights allow the vertical/horizontal mass to be changed. For example: if the user decreases the amount of counterweights used ,and moved this position back (higher on the scale number) the horizontal inertia of the tonearm would go down and the vertical inertia would go up.

Decoupled Counterweights

The effective mass of the arm horizontally is equal to to the sum of its component parts (It does not pivot) it needs to be as light as possible for low mass, however, making the arm too light sacrifices rigidity.

DOES MOVING THE WEIGHT OUT NOT MAKE IT LESS RIGID – A NO NO for this type of arm)

By decoupling the counterweight system horizontally, but not vertically, the mass is of the counterweight is not seen by the cartridge above a certain frequency.
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Now what I am hearing.
See first sentence under decoupled counterweights again.
IT NEEDS TO BE AS LIGHT AS POSSIBLE FOR LOW MASS, HOWEVER, MAKING THE ARM TOO LIGHT SACRIFICES RIGIDITY.

In my system when I replaced the counterweight bolt with a longer one and added a “little” more weight closer to the spindle there was noticeable bass change and overall presentation. I made the arm I believe more rigid by doing this. You can hear it in the sound. Based on the music you listen to and more importantly "the cartridge" you may prefer this or not. How much weight you add is a variable. The extreme limiter is bottoming of the spindle - but you will "hear" sonic problems “rumble” long before that according to Bruce - I have so far added just a bit more lead with no issues. I am not done with this yet.

I have discussed this with Bruce and he told me as the manual says that by doing this I am increasing the horizontal inertia but also he said that I am “increasing the vertical weight”.

VERY IMPORTANT

Don’t try this until you have figured out how to properly setup the arm. Level platter/level Spindle/Cartridge setup properly..
Bruce also told me that the effect will be different by cartridge/compliance. So I cannot say that you will get more or less bass attack or solid/leaner overall sound by doing this because -I don’t know what cartridge you are using and the compliance. I am basing what I am hearing on two test Empire 4000DIII MM cartridges 30 x 10(-6)cm/dyne that were mounted on an ET-2 and ET 2.5 at 19 PSI that I did my comparisons with in 2011.
This is a mod I feel u need to try for your own system/room / music preference because it costs nothing to do. Bolt was .75 cents. Lead weights are free from auto shops or order some from Bruce.
Cheers

it needs to be as light as possible for low mass, however, making the arm too light sacrifices rigidity.

I think what he's talking about here is the construction of the arm itself. If you make the arm too light by making the spindle wall thinner and the arm wand thinner, for example, the arm will loose rigidity. I do not believe the comment has anything to do with the position and number of counterweights, but I need to read the manual again to fully understand what is discussed in that section.

Are any of you able to update your virtual system now? I want to add my new air compressor, but when I log in to my account it says there is no system saved, even though I can view the thread.

The whole paragraph from page 9 of the manual:

"The effective mass of the arm horizontally is equal to the sum of its component parts. (It does not pivot) It needs to be as light as possible for low mass, however, making the arm too light sacrifices rigidity. By decoupling the counterweight system horizontally, but not vertically, the mass of the counterweight is not seen by the cartridge above a certain frequency and is lowered. This allows the use of heavier (more rigid) components in the tonearm design without increasing the effective mass."

He is, indeed, talking about the rigidity of the tonearm parts. Throwing weight at the I-beam near the spindle pivot does not increase the arms rigidity.

Ct, as I quoted before, moving the weight further out on the I-beam improved (in my set-up) the bass performance. By "improved" I mean better control, and weight; two things that don't always go hand in hand. I will say that the best results where always with the less compliant (double leaf spring) I-beam. I think the manual is clear about the benefits of doing this, and my results bear that out. I suspect that with the higher compliance spring (and a higher compliance cartridge/Empire) which you are using the results could be different. I strongly urge you to contact Bruce and get an I-beam with the less compliant double spring. In my set-up the difference is anything but subtle with much better air, detail and refinement.

Frogman - thx - yes I agree - I will contact Bruce and get this less compliant double spring before I do anything next.

Daniel - do you recall which I-Beam version you were using in your testing.

Cheers