Eminent Technology ET-2 Tonearm Owners

Richardkrebs,

I have finished testing Dover's mag configuration on my modified ET2

For the record you have NOT tested my ( Dover's ) configuration at all.

You have only tested magnetic dampening in the context of your own reconfigured version of the ET2. Your added lead mass has pushed the operating parameters of your ET2 outside of the original design.

Your ET2 is set up completely differently to mine in that :
You have rigidly coupled the counterweight to the arm.
You have added lead mass to your bearing tube.
You have added lead mass to the headshell.
You have increased the horizontal mass significantly over the standard arm.

The configuration I use is:
Decoupled counterweight in the horizontal mode ( spring bypassed )
Lightened tonearm
Minimal magnetic dampening

The level of actual magnetic dampening I use is as follows :
Shure V15VMR - 1 cupboard door magnet under the bearing tube at counterweight end
Koetsu Black - 1 cupboard door magnet as above
Madrigal Carnegie Model One - 1 cupboard door magnet as above
Denon 103 Garrott ( Aluminium/Boron hybrid cantilever/Weinz Parabolic diamond ) - none

Yet again, and you seem to do this with monotonous regularity, you misrepresent statements and arguments in order to justify your own point of view.

For those of you who may be interested in adding mass. I would bring your attention to Morch's latest arm which uses massive weights to increase horizontal mass. On their web site it does not say what these weights are made out of, but brass or stainless steel would be reasonable asumptions. Extra weight like this would dwarf the 30 or so grams I have added to my ET.

Your argument is wrong. The Morch arm is a pivoted tonearm. The ET2 is an airbearing tangential arm. The Morch applies its mass at the rotational pivot point. You have added lead mass to your ET2 at 3 points - the headshell, the bearing tube and the counterweight.

One needs to understand the physics as it applies to Linear Dynamics versus Rotational Dynamics. The added mass under these different conditions will have quantitatively different outcomes. You don't appear to have considered this at all.

Furthermore, the Morch website confirms my earlier statement that added mass, magnetic dampening and fluid dampening are not the same yet you contend that they are. Morch state on their website that mass increases inertia and has no dampening properties as I explained to you earlier. Morch use silicon fluid to dampen the motion in addition the added mass weights, again, which only increase inertia.
Your earlier contention that added lead mass is the same as fluid or magnetic dampening is incorrect.

Again I caution readers that adding lead mass in the manner advocated by Richardkrebs could potentially lead to cartridge and record damage when playing most records which are eccentric.

Why ? Because the added lead mass is loading up the cantilever.

Dover please re read my opening sentence.

"I have finished testing Dover's mag configuration on my modified ET2"

This clearly states that my ET is modified as anyone reading this thread recently would know. My testing was done in that context. That fact is obvious. The Dover Mag dampening test was as you proposed to Chris and that he asked me to try. I also took the opportunity to revisit earlier versions with strong and weak magnets independantly each end.

I have not said that mass, mag dampening and fluid dampening are the same other than that they all resist motion and that this resistance increass with frequency.

The Morch adds what appears to be considerable mass at a radius out from the pivot point. In so doing they have made a flywheel. Lateral movement of the cantilever mounted on a pivoted arm tries to rotate the arm about this pivot point. This added mass, flywheel, serves to resist this rotation tending to keep the cartridge still, a desirable trait. As viewed by the cantilever this is no different to me adding mass in the linear plane to the ET. Adding too much mass would result in unwanted cantilever movement due to record hole out of center problems. We agree on this, as you say it would load up the cantilever, but Morch with their flywheel do not appear to have reached that point nor have I with my arm.

Dover – I really do wish you had your ET2 up and running. The detail you remember is impressive.

Richard - that was a really nice post on your findings.
Thank you for taking the time to do this. Your attention to detail is very evident as well. BTW - Your recommendation for the ground on my second regulator has helped - thank you.
Also I found the “Why do we listen to music” on your website very informative. No affiliation to you or your site.

I want to ask (anyone) when we talk about dampening ....

Does damping not mean - reduce, diminish, dull - to a point that reduces some of “vinyl’s nasties”, caused mostly in this case with the ET2 tonearm – the off center hole - but we want to do this without taking away too much from the music itself ?

The effects of the magnets (small ones) so far to me is very subtle. Have not tried stronger neo magnets. I am not able to put magnets at both end of the manifold as my ET2 is on a pillar that only allows magnets at one end.

Is the effect of the magnets in my case subtle because, imo, I do not play really eccentric records. Or does the small amount of movement we are talking about even matter ?

Richard/Dover - would not significant movement in the ET2 spindle be required, to induce more than a subtle effect with eddy currents when using smaller magnets as I have been using on a stock spindle ?

I will say it can sound a little “nicer’ sometimes with the magnets on some lps. Lps are engineered all differently. On others the effect is very small if at all. There however seems to be more background/ambient info without magnets on those lps that I did notice a difference. I refer back to the car shock absorber analogy.

So does this not imply - trying to get the setup done right first - before you add any kind of dampening effect - even the oil trough ?

IMO - The good thing here is any ET2 owner can try these magnets very easily and decide for themselves. Hope we get more impressions from others.

I got a response back from Bruce that he is travelling. I did ask him about the manifold shims, and will also ask about his opinion on adding weight in the spindle itself - even if only 30 gms.

Very intriguing

Richardkrebs

para 1 - not obvious to everyone.
You are testing the effect of magnetic damping with an ET2 with rigid counterweight and high mass. Chris has been testing magnetic damping with partially decoupled counterweight and no added mass as has Frogman.

I have not said that mass, mag damping and fluid damping are the same other than that they all resist motion and that this resistance increass with frequency.

This simplistic view fails to differentiate between inertia and damping of motion.
During the course of this debate over the last few weeks you dont seem to comprehend the difference between inertia and damping of motion.

Inertia is the resistance to a change in its state of motion or rest. When you add lead to your ET tonearm you increase inertia. By increasing inertia the cantilever will flex more on eccentric records.
Damping is the retardation of motion once the movement has commenced. This means the cartridge can move straight away with an eccentric record, which results in minimal flex in the cantilever, and less distortion, but eddy currents generated by the motion of the arm relative to the magnet retards the oscillation of the arm and cartridge.

Adding lead mass creates higher inertia but does NOT retard motion.
Magnetic dampening has lower inertia and dampens motion.

I repeat again that the lead mass that you have added puts more load on the cantilever when the arm tries to move to accommodate an eccentric record.

Furthermore, with the higher mass of the added lead, when the arm moves there is more momentum, there is no control over this mass, and there is no damping of motion to minimize overshoot as the arm tries to correct.

As viewed by the cantilever this is no different to me adding mass in the linear plane to the ET.

Again - a very simplistic view of the world. Pivoted arms have tracking error and offset angle. The physics is quite different to that of a linear arm.

Adding mass

but Morch with their flywheel do not appear to have reached that point nor have I with my arm.

This is an assumption and speculative.
I could just as easily surmise that the Morch arm is so thin and lacking in structural integrity that it needs added mass and fluid dampening to control energy and resonances in the arm generated by a good moving coil cartridge.
Conventional mathematics says that adding mass to a flywheel, not only increases inertia, but it is harder to slow down. You are making the problem of navigating an eccentric record bigger than it needs to be.

Hi Chris - Yes I have a good memory. When we first imported a pile of ET2's we had in the shop an ET1. There was a big debate at the time that the ET2 had less bottom end than the ET1. The ET1 has a fixed counterweight. My business partner preferred the counterweight bolted up as per the ET1, but I found that gave a one note bottom end, lacking speed and articulation.
I experimented with the counterweight coupling and other ET2 mods quite extensively not only with a variety of TT's including Sota Star Vacuum, Townsend Rock, Roksan, Oracle and Final Audio TT, but also a variety of speakers including Martin Logan CLS, Apogees, Proac EBS, Proac Tablettes, Duntech's, vintage Tannoy Monitor Golds and many others - over the last 30 years.
Also have run the ET2 specifically with a wide variety of cartridges including Madrigal Carnegie, various Koetsu's, Van den hul Grashopper, Shinnon Red, Sumiko Talismans/Virtuoso's, Shure V15VMR, Denon 103 Garrott, Benz Reference and many others I've long forgotten.
I have also seen enough off centre cantilevers to last a lifetime from the misapplication of both tangential and pivoted arms.