Eminent Technology ET-2 Tonearm Owners

Richardkrebs.

If you prefer the sound of your ET2 loaded with lead and decoupled counterweight removed thats fine.

A couple of technical points though.

Paragraphs 1-3 : You miss the point here. Your quasi-mathematical arguments on resonant frequency are meaningless because the arm is more complex than what you appear to comprehend. You continually factor only one resonant frequency into your arguments to attempt to justify your opinion. The ET2 as designed has a multitude of resonances, which you appear to be oblivious to and ignore in your calculations. I use the word calculations loosely here, as I suspect your numbers are mostly guesswork.
You have ignored
horizontal/vertical resonance of the cartridge
horizontal resonance of the sprung counterweight
the horizontal/vertical resonance of the air bearing
natural resonances of the bearing tube/rigid arm wand
natural resonance of the counterweight assembly.

Count them up. This is the fundamental flaw in your postulations.
The arm is a precision instrument and is designed to have split resonances and variable vertical and horizontal mass in order to be tuned. The tuning is critical to optimizing the performance of any cartridge. For example

Bruce Thigpen
If the weight is coupled the system resonant frequency would be extremely low, a resonant frequency at 3Hz with a significant rise in response (6-12dB) results, which would affect tracking slightly because of the asymmetric position of the cantilever, we opt for splitting the horizontal resonance frequency into two points and lowering the "Q" which improves tracking.

Please note the comments from Bruce Thigpen "splitting the horizontal resonance frequency into two points". As I said there are multiple resonant frequencies to consider.

Clearly you still don’t get that your home brew efforts to remove this tunability by rigidly coupling the counterweight assembly result in a bass lift of 6-12db and increased distortion. Your addition of lead mass will increase these distortions further. Believe me Richard I have heard it, you apparently cannot.

Richardkrebs
Re my question re interaction between the two spring rates, …
I started thinking about this when Dover commented on the superior transient performance of his unipivot. The idea further coalessed when the tests were done with loosening the CW arm bolts. This would change the Q and possibly the res frequency of the CW assembly. Potentially reducing any interaction between the two springs, but not eliminating it.

My comments on the Naim Aro unipivot were pertaining to the superior preservation of the leading edge of notes - this is quite different from “transient performance”. Unipivots are mechanically coupled, whereas an air bearing is not rigid and loses some of the leading edge. It has nothing to do with Q as you claim. The addition of lead mass will alter the dynamic stiffness and compromise the performance of the air bearing. Capturing the leading edge requires secure tracking and speed, both of which are compromised by your addition of lead mass.

I do agree that it is possible that the spring could have some issues, and that is why I believe I got an improvement by using teflon rather than spring steel for decoupling.
Contrary to what you hear, when I trialed increased mass and coupled the counterweight rigidly with a low compliance cartridge I got bass that lacked coherency and was out of tune as is predicted by the maths and verified by Bruce Thigpen’s extensive testing. As a matter of point I reached this conclusion in 1986, well before Bruce published his test results. The website did not exist then. Frogman, Slaw and Chris have also come to this conclusion with a variety of cartridges and systems.

You choose to throw away two of the fundamental principles of the ET2 – maintaining a low horizontal mass and the ability to tune the horizontal and vertical resonances by using decoupled I-beams and variable effective mass for optimum performance.

It is disappointing that you are so rigid in your fixation with mass as I think you are missing an opportunity to substantially improve your system.

The preservation of low horizontal effective mass even with low compliance cartridges as prescribed in the manual and supported by Bruce's test results ensures the bass does NOT have a lift of 6-12db and improves tracking.

By my calculation AND what I have heard and experienced you have a bass lift and increased tracking distortion from your removal of the decoupled I-beam and the lead mass that you added.

If you prefer that, fine, but lets be clear, you can not call the misguided conversion of your ET2 into a high mass rigidly coupled arm an upgrade.

This picture has been posted a couple times on this thread already.
This is the third time
I asked previously if anybody knew the owner.
This ET2.5 to me is a unique expression.
It represents to me individual passion and interpretation to the extreme.
When I posted a picture of Richards setup on this thread I placed it at a similar level in my mind - however.
Richards setup goes beyond as it includes a customized TT that is integral to his ET2 tonearm as well. It is one as a whole?
Whether Richard wants to run his tonearm in a rigid way or decoupled is not of concern to me.
His setup is unique and has been through many hours of trials I am sure that i can not even begin to think about. He is able to reverse changes to it and run it de-coupled if he wants.
As long as he is happy listening to music the way it is – great.

Now with that anyone that tries a rigid I Beam, likes it then adds lead dampening as well with a stock ET2 or ET2.5.

Hey - its a free world. Even if they are not aware of the parameters they are changing.

At least we have outlined the parameters here for those that read the thread so they know.

I have placed the ET2 and ET 2.5 on a direct drive, idler, belt and finally string drive TT.

On each different table the ET2 / ET2.5 sounded different.
I am willing to bet all our TT setups are different. Not one the same.

All our setups outside of the TT setups are definitely different including our rooms.

Selfishly - I would like for Dover to bring a couple of nice bottles of wine over to Richards place and have a listen to his tonearm in coupled and decoupled fashion with Richard using Dover's favourite lps.

Same room, same gear.

Then for both Richard and Dover to post separate impressions here.

That would be priceless, to me.

Cheers

04-16-13: Richardkrebs
... Later on in the thread, 03/14/13, Chris published the actual weight of the ET2.5 being only 8gms heavier than the ET2. This means that ET did not use the same cart parameters when giving Chris the original info..

Bruce has confirmed same cart parameters were used.

Dover
The arm is a precision instrument and is designed to have split resonances and variable vertical and horizontal mass in order to be tuned. The tuning is critical to optimizing the performance of any cartridge.

Dover – I agree with you and the key for me is “any” No limitation on the cartridge –imo. So far anyway.

imo - Someone just getting into analog with an ET2 doesn’t have this tuning knowledge to start with. It is gear and room specific so takes time to acquire. Looking back now I think I got to about - 6 out of 10 in the beginning; years ago and thought it sounded great. I thought I had it running good – but I didn't understand. The rest comes with experience; Experience comes with time, time in listening to it in your own room and tuning it with your own gear. I believe if had this thread 10 years ago I could have fast-tracked. But then I would have missed out on some fun.

Chris,
This is strange.
For the example BT uses in the manual, pages 48 and 49. The res freq for the ET2 with a 30cu cart we get around 4.7 hz.
For the ET2.5, assuming it is only 9 gms heavier the res freq with the same cart would drop to around 4.2 hz

Perhaps BT could clarify this?

Thanks .

Chris,

04-16-13: Richardkrebs
... Later on in the thread, 03/14/13, Chris published the actual weight of the ET2.5 being only 8gms heavier than the ET2. This means that ET did not use the same cart parameters when giving Chris the original info..

Bruce has confirmed same cart parameters were used.

This is a good example of someone who doesn't have the physics and maths knowledge to apply it correctly. I usually dont bother to check Richardkrebs maths because the underlying assumptions that he uses are usually wrong to start with.

Dover
The arm is a precision instrument and is designed to have split resonances and variable vertical and horizontal mass in order to be tuned. The tuning is critical to optimizing the performance of any cartridge.

Dover – I agree with you and the key for me is “any” No limitation on the cartridge –imo. So far anyway.

imo - Someone just getting into analog with an ET2 doesn’t have this tuning knowledge to start with. It is gear and room specific so takes time to acquire. Looking back now I think I got to about - 6 out of 10 in the beginning; years ago and thought it sounded great. I thought I had it running good – but I didn't understand. The rest comes with experience; Experience comes with time, time in listening to it in your own room and tuning it with your own gear. I believe if had this thread 10 years ago I could have fast-tracked. But then I would have missed out on some fun.

Chris - I agree with your last post and that is why it is vitally important that new owners get correct advice on how to set the arm up correctly.

People very seldom read the manual until something doesn't work as expected - sound familiar.

We should be encouraging ET2 owners to explore the opportunites afforded by the tunability of the ET2.

Setting the levels accurately
Choosing the correct counterweight mass for the cartridge
Dressing the cables
Setting the VTA correctly

When all these are correct the tuning of the I-beam becomes much easier to hear.

We should not be encouraging owners to bastardise the arm by removing its primary design advantages as Richardkrebs continues to do.

Fortunately I have the advantage of importing and selling these arms many years ago and personally set up approx 12-15 ET2's in one year alone. TT's included my Final Audio Parthenon, Sota, Roksan, Townsend ( Rock ), Oracle, Goldmund, VPI and others I've forgotten; cartridges included the usual Koetsu's, Garrotts, Carnegie, Benz, Van den hul's etc
I would never install an ET2 on a suspended TT such as Oracle or Linn because of the shifting mass as the arm tracks across the record. Sota was OK as the suspension is hung and the high mass subchassis is inherently more stable than the Linn/Oracle type TT's.

I disagree with your comment on system dependency. In my experience the sound improvements from the correct set up and application of the ET2, including tuning the I beam/counterweight in it's standard configuration can be heard in any system. That is why Frogman, Slaw, yourself and myself have all come to the same conclusions on tuning the I beam albeit with different systems. What we probably have in common are a good set of ears and an open mind.