Eminent Technology ET-2 Tonearm Owners

Richard, that exactly what I have done. I run AudioNote wire from cartridge clips, underneath the arm wand (secured at two points along the span), then forming a loop from the back of the arm wand to the pillar, all the way to my phono pre, where it is hardwired to the circuit board. Not particularly unatractive and works very well.

Frogman.
Excellent! You have inspired me to do this with mine.
Thanks for the feedback.

Richard,

My tonearm wiring also runs outside of the wand. There is a photo of it in my system page.

Courtesy of Chris, here is a composite pic of my ET showing the wiring arrangement. The current arrangement is the same, except that I am now using the original/lighter aluminum arm wand instead of the magnesium with wrap shown in the pic. Also, the damping trough is now disengaged, and I have added a fridge magnet for damping.

http://cgim.audiogon.com/i/vs/i/f/1364852043.jpg

Ketchup and Frogman.

Thanks for the pics.
Can either of you describe the changes with the wire outside. I would expect a more lively, detailed, precise presentation.

Seeing the manifold like that reminded me of the shim/grub screw set up. Has any one made any progress on this?

Richard, the only time that I have not had the wiring on the outside was during the first two years or so that I had the arm (about twenty years ago!) when it was wired internally with VDH silver. I changed the wiring (Cardas) to reap the benefits of using a continuous run from cartridge to preamp. At the time, I did not consider the possibility of benefits due to the sheer fact that the wiring would be external. The improvement in sound was very significant, but I attributed it to the elimination of several solder joints and connectors along the signal's path. I have since changed the wiring two more times; Discovery, and currently AN which is my favorite by far.

Frogman.
20 years! It gets scary when you start thinking back doesn't it?
I also have a continuous run to the pre but put it inside purely for cosmetic reasons. My thoughts would be to route it such that it stands off from the wand a little. In theory there would still be some interaction between wand and wire, due to proximity. That said, the level of this may be just too tiny to notice. Have you per chance tried this?

Richard, it does get scary! I have not tried that, but I will. Thanks for the tip; I will report back.

Hi Richardkrebs

Had a very good Easter beak, very relaxing. Thank you for asking.

Was wondering, now that you know how the ET2 works, whether you had found time over the long Easter break to remove the lead from your arm, put the decoupling spring back in, dial in the vertical effective mass ( less lead further out for your cartridge ) and set the I Beam resonance below the arm resonance as prescribed in the manuals.

Frogman, Chris & Slaw have all found significant gains with the correct decoupling strategy employed. Frogman has reported significantly more bass information loosening off the end cap as per my suggestion some weeks ago.

I would be very interested to hear what sort of improvements you get when you get the arm back to standard configuration.

Looking forward to hearing how it goes.

ET2 ET2.5 - Aluminum Gooseneck Update

Just a reminder on this initiative. I will post a reminder once more in a couple of months.

I have received some replies and we have four people so far who are interested in aluminum goosenecks. One size fits the ET2 and ET 2.5. This would replace the current carbon fibre part that joins the armtube to the spindle with an aluminum one.

If enough people are interested we can get Bruce to do a special run of them. The price would be based on the number of people interested.

If interested please contact me at bcpguy(at)bell(dot)net for details

I am not affiliated with this other than wanting one myself. I am one of the four people so far.

Cheers

Richardkrebs
I don't have any first hand experience with arm pods. They tend to go against the grain so to speak, in the quest for absolute dimensional stability between platter and arm. That said it seems that there are many admirers of this approach and, other than to quote others, it would not be prudent for me to comment on the sound of something I have not personally heard.

The best statement I have read yet from someone that has not tried them. A refreshingly honest answer. Thanks Richard.

Anyone the least bit curious about them can check out the Copernican thread. Some "robust debate" there.

Cheers

Dover
" self taught engineering school of fabulosity."

You go too far....

I have a tertiary education in engineering. I hold an aircraft avionics qualification and a radio technicians certificate. I teach hydraulics and electronics to paying clients.

My company employs 52 people across two countries.
We specialize in the design and building of complex servo electro hydraulics.
Recent projects have been damper doors for jet engine power stations in Oman and Iraq.
These doors, 7 meters square, are required to swing thru a 90.degree arc and stop precisely in position. Fractions of a mm are possible. The doors need to do this at both high, emergency close speeds and normal slow rates. With the multi mega watt engine buffeting it with an air stream just below supersonic.
Get the Q wrong with something as massive as this and it either fails to reach the go to point in time or it shakes itself to destruction. We usually target just below critically damped to give added safety.
My public liability does not cover destroying a multi billion power station.
I understand resonance, Q, time constants, mass damping et el.
The survival of my company and potentially the power station workers and my staff depends upon it.
You cannot begin to imagine the pre qualification process a company has to go thru to be even considered to quote on projects like this.
Compared to design work like this, a tonearm is relatively mundane. Certainly a whole lot less stressful.
I know how the ET2 works.

The audigon thread ghosts of the past seem to be hitting the ET2 thread.

Came across this over coffee this morning. A custom x- Maplenoll Athena setup with an ET1 modded. No affiliation with the person or ad. Just thought you guys would find it interesting.

http://www.canuckaudiomart.com/details/649054055-deconstrata_x_maplenoll_athena/

Double posts and thread ghosts of the past. How does that happen?

Chris.
It is good to see that analogue gear is holding its price. Maybe the current trend of interest will continue. My sons and their friends are keen to spin records. A welcome change away from the broken washing machine music one usually hears leaking out of their ear buds.

Double posts and thread ghosts of the past. How does that happen?

My theory - Its all about those damn 0’s and 1’s. Problems arise when you try to merge an old system of 0’s and 1’s, with a newer system of 0’s and 1’s. A few 0’s and 1’s get misplaced, duplicated sometimes.

Richard - thats nice to hear about your sons and their friends wanting to spin records. I have been waiting patiently with my 2. I have hoarded enough gear to make systems for both plus my wife if she wants to spin Motown nonstop in another room somewhere. I have almost lost all hope and am considering a large 2013 Spring Sale to cash in and spend the money on myself and pay for recent purchases.

04-07-13: Richardkrebs
Double posts and thread ghosts of the past. How does that happen?

Richardkrebs – Audiogon has advised that it looks like it was double posted by the original author – that’s you Richardkrebs.
No ghosts involved. Is it possible that whilst sleepwalking, on the night of 07-04-2013, you reposted your earlier post of 03-30-2013?

For the benefit of readers, Richardkrebs original post reads

03-30-13: Richardkrebs
Dover
" self taught engineering school of fabulosity."
You go too far....
I have a tertiary education in engineering. I hold an aircraft avionics qualification and a radio technicians certificate. I teach hydraulics and electronics to paying clients.
My company employs 52 people across two countries.
We specialize in the design and building of complex servo electro hydraulics.
Recent projects have been damper doors for jet engine power stations in Oman and Iraq.
These doors, 7 meters square, are required to swing thru a 90.degree arc and stop precisely in position. Fractions of a mm are possible. The doors need to do this at both high, emergency close speeds and normal slow rates. With the multi mega watt engine buffeting it with an air stream just below supersonic.
Get the Q wrong with something as massive as this and it either fails to reach the go to point in time or it shakes itself to destruction. We usually target just below critically damped to give added safety.
My public liability does not cover destroying a multi billion power station.
I understand resonance, Q, time constants, mass damping et el.
The survival of my company and potentially the power station workers and my staff depends upon it.
You cannot begin to imagine the pre qualification process a company has to go thru to be even considered to quote on projects like this.
Compared to design work like this, a tonearm is relatively mundane. Certainly a whole lot less stressful.
I know how the ET2 works.
Richardkrebs (Answers | This Thread)

This was posted again on 07-04-2013

04-07-13: Richardkrebs
Dover
" self taught engineering school of fabulosity."
You go too far....
I have a tertiary education in engineering. I hold an aircraft avionics qualification and a radio technicians certificate. I teach hydraulics and electronics to paying clients…. )

If this is the case, what possessed you to repeat your qualifications and work experience yet again?

Nevertheless, thank you, you have reminded me - I do have a few observations and suggestions.

You seem to object to my observation regarding your self taught engineering. I note from your post and from your website that you encourage us to read that you have some electrical trade certificates. From your website you joined the company as a storeman, after attaining these electrical trade certificates. There is nothing on the website that suggests you have had any formal tertiary education in the fields of “engineering” applicable to the design of the ET2, specifically the physics and mathematics of this arm.

This being the case, I understand more clearly now why you have difficulty comprehending the complexity of Bruce Thigpens design.

I draw your attention to Bruce Thigpens background. After completing a business degree, Bruce commenced working for W.H.Coloney, an engineering company specializing in mechanical and civil engineering. Bruce project managed the development of the Coloney air bearing TT & tonearm ( now the Walker ). He was taught air bearing technology by qualified civil & mechanical engineers.

Bruce returned to university as a post graduate student, to study Physics, Maths & Audiology to ensure that he had a comprehensive understanding of the physics and mathematics involved in developing air bearing TT’s and tangential air bearing tonearms and the outcomes. Bruce holds many patents pertaining to air bearing tonearms and others such as patents on vacuum hold-down on records.

I studied Structural & Mechanical Engineering, Physics, Maths & Inorganic Chemistry at university in the late 70’s, before switching to Finance.

Now to the issue at hand.

For some months now you have argued that users of the ET2 tonearm should add lead mass and remove the decoupling from the I beam/counterweight assembly.
This advice on your part is in direct conflict with the set up procedures in the manual.

I quote from 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.

More important than tracking, the intent was to reduce the modulation effects of low frequency energy (FM and AM) that increase distortion in the cartridge,

Bruce Thigpen’s contribution affirms my statements over the past 2 months that your fixation with adding lead mass to the arm and coupling the I-beam will increase distortion, affect tracking and produce an unnatural bass lift in response. My own analysis has long been based on a thorough understanding of the design principles and physics involved.

If you go to the Eminent Technology website and read the ET1 manual ( that’s the arm that precedes the ET2 ) you will discover that the ET2 was a design decision to move away from the high mass/fixed counterweight model utilized in the design of the ET1 to the low mass decoupled counterweight model utilized in the ET2. These new design considerations embodied in the ET2 resulted in substantive improvements in the quality of sound reproduction.

The decoupled I-beam methodology employed by Bruce Thigpen in the ET2 is designed to minimize horizontal inertia and ensure the resonance of the I-beam and counterweight remains below the horizontal resonance of the arm so that the 2 resonances ( arm and beam ) do not couple together to produce a large peak at the arms resonant frequency in the bass.

All tonearms will have a lift or peak in response at their natural frequency. The tuning with the I-beam (decoupled) is designed to reduce this natural bass peak at the resonant frequency of the arm to produce a flat bass response. This is illustrated in the graphs on Bruce Thigpen's website where he has published test results.

The addition of lead mass that you continue to advocate goes directly against the design of this tonearm.
The rigid coupling of the I-beam and counterweight that you advocate is contrary to these stated design principles.
Furthermore you acknowledged in your posts dated 03-19-13 and 03-20-13 that you have only just worked out how the decoupled I-beam works after some 25+ years of ownership.

03-19-13: Richardkrebs
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.
03-20-13: Richardkrebs
The thought that there may be more going on with the decoupled counterweight was triggered by your post where you quoted BT where he said that the ibeam had a natural frequency of 2-5 hz. ,

In light of this newfound knowledge and your assertion that you now understand how the arm works, including the I-beam, I made a polite inquiry in my post dated 04-02-13 if you had had time over the Easter break to set up your ET2 correctly as per the manual.

Hi Richardkrebs
Was wondering, now that you know how the ET2 works, whether you had found time over the long Easter break to remove the lead from your arm, put the decoupling spring back in, dial in the vertical effective mass ( less lead further out for your cartridge ) and set the I Beam resonance below the arm resonance as prescribed in the manuals.
Frogman, Chris & Slaw have all found significant gains with the correct decoupling strategy employed. Frogman has reported significantly more bass information loosening off the end cap as per my suggestion some weeks ago.
I would be very interested to hear what sort of improvements you get when you get the arm back to standard configuration. ,

You have not responded. Can I assume that you have no interest in setting your ET2 tonearm up correctly?

It is clear from your continued denial of fundamental physics and mathematics and your statements disagreeing with Bruce Thigpen and myself in the design and implementation (set up) of the ET2, your continued fixation with adding lead mass and removing the decoupling from the I beam/counterweight assembly, that you do not have sufficient understanding of the principles involved in the design of this arm.

These are fundamental principles of physics, for which you would be better placed to debate if you had some formal education that is wider than what one would infer from your posts. Anyone who understands physics would not for one minute contemplate the homebrew mods you advocate.

I quote direct from the ET2 Manual p29

ET2 Manual p29
It is desirable in most cases ( low to medium compliance cartridges 5x10 dynes/cm – 20x10 dynes/cm ) to use the minimum number of weights, far out on the cantilever stem. This decreases the horizontal inertia of the tonearm while increasing its vertical inertia. ,

Readers should be aware that this is the exact opposite of what Richardkrebs continues to advocate. Richardkrebs is advocating increasing the horizontal inertia for low compliance cartridges – the opposite of what Bruce Thigpen recommends.

Richardkrebs, my recommendation for you, if you are serious about owning and operating an ET2, would be to enrol in some Physics and Mathematics papers at university. That may help you to comprehend the principles that make this an excellent arm when set up correctly.

I would advise readers and ET2 owners to ignore Richardkrebs erroneous recommendations and follow the set up procedures outlined in the ET2 manuals that can be found here.
http://www.eminent-tech.com/main.html

Frogman, Chris(Ct0517), Slaw and myself have all found significant gains with the correct decoupling strategy employed. Furthermore Frogman has reported significantly more bass information loosening off the end cap as per my suggestion some weeks ago.

My own experience with tuning the decoupled counterweight correctly and using a lower weight counterweight further out on the I-beam for low compliance cartridges as recommended in the manual yielded significant improvements in speed and articulation, transparency of soundstage and lower distortion, exactly as predicted by Bruce Thigpen’s substantive testing and published results.

No ghosts involved. Is it possible that whilst sleepwalking, on the night of.....

I suffer with this disorder called sleepwalking. I didn’t know it but my wife (bless her soul) did a personal study on me. She made we aware of the results later.

I apparently did the most sleepwalking after consuming certain amounts of red wine from downunder. Something about it having to do with certain types of proteins from that region, reacting to type C audiophiles, especially after listening to Pink Floyd - The Wall LP.

The proteins kicked in after falling asleep for 2 hours. Just enough to induce motor movement to walk around, without being conscious. It has me worried as I really like the wines from downunder and I really like that LP too.

Can you guys recommend a good cabernet sauvignon from downunder that will not break the bank and is safe ?

BTW – On another front - I understand that Canadian Ice Wines have become quite popular especially in the far east. It has come to my attention however through the media; that counterfeit Canadian ICE wines are now being made in the far east. Content questionable. Beware and be safe.

One of the above two stories is true.

http://www.winespectator.com/webfeature/show/id/44430

ET1 and ET2 Trivia Question.

How many ET1 and ET2 tonearms had been produced and sold by the mid 80’s ?

Any idea on the ET1 versus ET2 sold ratio ?

Hi Chris

“Can you guys recommend a good cabernet sauvignon from ‘downunder’ that will not break the bank and is safe?”

After decades of research (not backed by multiple degrees mark you), I can offer an opinion that might help (I won’t say satisfy, as one man’s wine might be another man’s poison, thus safety not guaranteed, but works for me!

We (myself + TSO - The Significant Other), are fond of rich, fruity, gutsy Australian reds. Gutsy, as in full bodied – I can’t bear rough stuff.

What has become a staple is Taylors Shiraz, preferably 3 to 5 yrs old (if you can keep your mitts off it that long) and warm, not cold, temp wise. Don’t sweat over, ‘Oh it’s not Cab Sav,’ we’ve drunk a lot of that also.

Warning: you will enjoy life a lot more.

Whether your arm is lead augmented, or made of balsa wood or unobtanium, or setup according to celestial directives, becomes less important. You will not be very likely to write epistle length diatribes.

BTW, so you aren’t confused in future, I’m thinking of acquiring an alias (false name): BenDover.

John47
The thread is about the ET2. Your facetious comments demonstrate that you have no respect for the designer of the tonearm and clearly do not understand and are not interested in how it works. Not for one second could anyone consider you to be an audiophile.

I have converted. To an out “e” from and in “e”
The attached pic shows my temp setup before/after - along with the lowered lead weights as well.

http://cgim.audiogon.com/i/vs/i/f/1365100316.jpg

The pic is at a bit of angle and not horizontal.

It’s a subtle change with the lead weights in the positioning but musically very evident in my room. I increased the VTF by doing this and had to move the weights back. I also had the wiring off the armtube totally and it sounded good but I felt it was an incident waiting to happen with me personally. Especially with those Downunder wines.

I did a crude braid on the wiring in the photo only to the end of the armtube. They are then separated. They affect the arm less this way.

I knew there were two things for sure in life I was no good at. Tying a tie and making a smooth bed. Now I know there are three. Making a nice braid. Will ask my daughter for help with the braiding when she comes home from university. My wife is just shaking her head. She has learned to stay 6 feet away from the turntable at all times.

Fwiw –

From my own personal experiences a happy face loop works better than an upside down one for ET2, ET 2.5 as they are designed to be free and IMO it has less effect on the tonearm.

The upside down loops I have used all forced me to use more rigid materials for support and affected arm movement.

One example of this with me.

http://cgim.audiogon.com/i/vs/i/f/1325532980.jpg

The air tube and wiring are part of other air bearing tonearm designs for damping as we have learned here. Choose your own poison.

I also position my preamp higher than the wires right next to them so there is a natural happy face loop going to it.

Cheers

John47
What has become a staple is Taylors Shiraz, preferably 3 to 5 yrs old

Thanks for the recommendation John !

Guys - I will reveal the answer to the trivia questions tomorrow morning. Any guesses ?

Dover - you probably know the answer as you were a dealer/distributor - don't give the answer away.

Cheers

Not an audiophile! Never mind.

But I do know what 'diatribe' means:

"A forceful and bitter verbal attack against someone or something."

Yes, John47, diatribe does indeed describe your contributions to this thread. However, please continue to waste more of our time posting your vitriol as this appears to be your preoccupation.

ET1 was introduced in 1983, ET2 in 1985. I would guess that by the end of the second year after the 2 was introduced, the ratio of ET2/ET1 sold was already 20/1 simce the 2 was much more popular. I would guess that by the end of 1987 (1988+ would no longer be mid-eighties?) 400 ET2's had been sold. Just a wild guess.

04-10-13: Frogman
ET1 was introduced in 1983, ET2 in 1985. I would guess that by the end of the second year after the 2 was introduced, the ratio of ET2/ET1 sold was already 20/1 simce the 2 was much more popular. I would guess that by the end of 1987 (1988+ would no longer be mid-eighties?) 400 ET2's had been sold. Just a wild guess.

Frogman - Thanks for participating in the ET1/ET2 trivia question!

Any more guesses before the answers are revealed ?

A hint to the ET1/ET2 trivia questions.

The answers can be found within here but only for a few more days.

Answer to the ET1/ET2 Trivia Question.

If you select page 3 on the ebay ad and magnify the page on your screen you are able to see the text.

************************************************************

“The ET1 was introduced at Chicago CES in 1983 and Tonearm 2 followed in June 1985. About 300 ET1’s and 2000 ET2’s have been sold to date throughout the world.”

************************************************************
So at the time of this publication - 2000 ET2’s 300 ET1’s. Approximately a 6.5 – 1 ratio.

So unlike the introduction of the new "Coca-Cola" it appears based on the numbers, that the "general" audiophile public liked - and still likes the ET2 and its younger but bigger brother ET 2.5.

It would be interesting to know what the ratio is between ET 2.5 versus ET 2.0.

I am not affiliated with the ebay ad - although I admit I am tempted to bid on it - just to read the reviews and see if anyone actually explained how they setup the counterweights.

**Congratulations Frogman !**

You are the winner of the trivia contest.

Well ok ........ you were the only official entry.

Actually I did get one offline entry that came closer – but contest rules ((reads the really fine print)) stipulated the entries needed to be posted here.

Cheers

Frogman: Can you explain the outer wire (it seems) that you have wraped around your armwand?

John47: What? I assume you are making a statement. Can you tell me what or how it pertains to this thread? Thank you.

Hi Slaw – if you go back a few posts you will see in one of them that Dover introduced a new term to us - well I should say he introduced it to me.

“robust debate”

Now in my opinion only, this “robust debate” sometimes brings in conversations outside of the box.

The box here being the ET2, ET2.5 tonearm.

I have always found that thinking and talking outside of the box is generally a good thing in life.

It helps to understand how each of us arrive at our own decision points - in this hobby.

Now if I am talking gibberish and have misunderstood – wouldn’t be the first time :^(

May Dover and John47 correct me. We are all big boys here after all.

BTW - I am just as guilty for posting a bunch of stuff here that has nothing to do with the thread. The latest I believe was asking for wine recommendations. Mind you I would be consuming a good percentage of it listening to music with the ET2.

Cheers

Slaw, welcome back to the thread. What you see on the arm wand (magnesium) is a very exotic rubberized cloth material used as a wrap, and sourced from a local supplier, called Lowe's rubberized cloth gaffer's tape :-)

In an attempt to tame my Vandenhul and Shelter MCs' aggressive top end, I wrapped the arm for extra dampening; it worked well. When I began using MM's again, I went back to the original lighter wand which works better with them.

Chris, eliminate the competition, I always say :-) Man, I wasn't even close! Over 2000 ET2's sold; I would never have guessed the number to be that high. I figured 1200 or so by the time the arm was discontinued (before being brought back). When was that article written?

eliminate the competition, I always say :-)

Frogman - remind me never to enter a sports competition against you. I could get hurt.

Well curiosity killed the cat - my intentions were good. I figured put in a decent bid; win that auction for the ET2 reports; scan them and make the info available here.

So as the ebay clock winded down I strategically waited to make my move.
Nothing gets my heart pounding like an ebay bid.
59 seconds left I put in my bid and received the message back - No shipping to Canada !! sigh....

I will ask Bruce about the date - a little later. I am lying low with him for a bit - he has received so many emails from me.

Cheers

Lets look at things again.
I am officially retracting my retraction to Thekong regarding the ET2.5. Here is why.
When I realised my obvious mistake in thinking he was going to place a rigid CW arm on an ET2, when in fact he was proposing to use one on an ET2.5, I looked at the figures for this arm.
On 03/14/13 Chris posted the Horizontal resonant frequencies for the two arms. ET2 5-6hz ET2.5 2-3hz.
I already knew the horiz mass of the ET2, so calculated the mass of the ET2.5 assuming the same cartridge mass and compliance was used for both arms( a reasonable asumption)
Res freq is proportional to the square root of the inverse of the mass. In other words 4x mass = 1/2 res freq. Since the ET2.5 freq range was approx 1/2 the ET2, it implied that the ET2.5 was 4 x heavier, making it over 100 gm. This surprised me but in the absence of any other information, I took it on face value.
From experience it would be problematic if Thekong were to add a rigid weight to this apparently already heavy arm. 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. Thekong, your call obviously but if I were you I would try a fixed CW arm provided it is really rigid.

Re my question re interaction between the two spring rates, cart and CW. I raised this question, not because I had suddenly "understood" how the ET2 worked but because the idea that having two springs driving the same structure could actually have a down side. 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.
When I fixed the CW and added further mass and used a low compliance cart, there was an unexplained positive side effect. Focus and sharpness improved. Transients were better. It was some years ago when I made this change and while liking the improvement, I didn't put too much thought into 'why'. While I did not post these positive results. My question to the fellow posters was " could the interaction between these two springs be a problem." I don't know, but it is a valid question and the graph I posted suggests that they do "talk" to eachother. My thinking was that there may be a link between the transient improvements I acheived and the use of a swinging CW.

When I first purchased the ET2, I set it up as per the manual, to the point of obsession. As with all of my gear, I wanted to extract every tiny bit of performance. In standard from, it was best as per manual, with the slight adjustment of swinging the Ibeam down as Chris has posted.
Years later I started to experiment. The result is what I have now. It is just my opinion, no more or less valid than anyone else, but I believe that it is significantly better than a standard ET2, when using low compliance carts.

We can debate this from first principles all we like, but the proof of the pudding is in the hearing. What does it sound like, how does it perform? This is evaluated with our ears.

I will not be degrading my arm by converting it back to standard form.

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.

Hi Chris,

Regarding the modified ET you posted, I believe it was made by a guy in China. I read an article probably 7-8 years ago, in which he detailed the process of the modification. Unfortunately I couldn't find that article anymore, but it was written in Chinese anyway.

If I remember correctly, he was using it with the Micro 8000 turntable, and the black circular arm base was actually from a Technics 1200!

He sold the ET and Micro later and manufactured his own turntable and air-bearing arm. You can see some photos of them here:

http://www.hdavchina.com/html/72/n-2872-2.html

I am not sure, but I don't think the brand exist anymore.

Hi Thekong – thanks! I like to solve mysteries. They keep nagging at me. Third time is a charm here as they say.

Thanks for the info to that site too with the translator - Obviously someone very passionate about vinyl and the interaction with it.
Cheers Chris

Richard - I don’t pretend to understand the math. I will ask Bruce again when I can for clarification.

Dover - Lets face it – the manual contains great information but is in a really bad need of a re-write with some pretty fonts that audiophiles will actually like to read. A summary two pager to get up and running is also needed to hit the top 10 points.

Hell 643 posts on modifying a bloody tone arm!
It's so great seeing people I have known for over 25 years write such stimulating posts.
It's time we all met for a coffee. Mark.

Welcome to the thread Mark.

It's time we all met for a coffee.

For some reason I assumed you were from downunder, but when you said “coffee” you confused me. I expected to see flat white ?

Good things come from Downunder I have learned. We already discussed the wine.

But I was a little surprised at the Australian recommendation and not a NZ one.

Well sometimes the goose lays a golden egg in NZ.

But in this case its silver colored. And it’s not an actual egg but part of the Goose herself – the neck in this case.

We affectionately call it an ET Gooseneck here.

Just received

Sorry Mark – another ET2 mod :^(

Thank you Richard Krebs for coordinating.

Hell 643 posts on modifying a bloody tone arm!

At least we know what “this” thread is about ?

Cheers

Maths and Physics.

A few days back I wrote that the res freq of the arm was proportional to the square root of the inverse of the mass and stated that there was a discrepency in the ET2/2.5 comparitive figures that Chris had posted. This because the figures showed a halving of resonant frequency for the ET2.5. I speculated that this meant that the two sets of figures must have been taken under different circumstances. Chris followed up my post up with a question to BT where Bruce appeared to say that no, the measurement conditions were the same.
This did not make sense and was contrary to resonance theory. Since I did not know the actual question Chris asked Bruce, I decided to contact Bruce myself for clarification. Below is my question and Bruce's answer.
Note Bruce uses the phrase "everything else is the same". This could be where the confusion came from.



On 4/18/2013 10:22 PM, Richard Krebs wrote:
> Bruce.
> Good day to you..
>
> My question concerns the horizontal resonant frequencies of the ET2
> and ET2.5 Chris spoke to you about this some time ago and you gave him
> a range of frequencies 5-6 hz for the 2 and 2-3 hz for the 2.5. Chris posted your info on the ET2 audiogon thread. The range of frequencies for the ET2 was approx double the ET2.5 This is confusing if the same wand, cartridge weight and compliance was used for both arms, as it implies the the ET2.5 is around 4 times heavier in the horizontal plane.
>
>
> For a 8 gm cartridge of 30 cu I get horizontal resonance figures of around 4.7 hz and 4.2 hz for the ET2 and ET 2.5 respectively.
> Are my figures correct? If not where am I going wrong?
>
>
> Many thanks .
>
> Richard.
>
>

Richard,

Your figures are correct and closer to reality. The only difference in mass is in the spindle, everything else is the same. The spindle adds about 10 grams to the horizontal inertia figure and almost nothing to the vertical inertia. I hope this helps.

brucet

As you can see Bruce has confirmed my figures are correct and the resonant frequency of the ET2.5, for the same cartridge, is not half that of the ET2, but only slightly less, exactly as I calculated.
If any one wants to confirm this for themselves, they need only go to the horizontal frequency formula in the ET2 manual. Choose a total mass (Mc plus Ma) of say 40 gm.(simulating an ET2). Insert the compliance figure for your chosen cartridge and calculate the res freq. Now recalculate with Mc plus Ma equal to 160 gm. You will get 1/2 the original number. Recalculate again with Mc plus Ma equal to 50 gm (simulating an ET2.5) you will now get a figure only slightly lower than the original.

So what can we conclude from this.

Someone who understands the math and physics around the ET2/2.5 would know that......
a)....it would be obvious, from a mile away, that the resonant frequency of the ET2.5 with the same cartridge would not be 1/2 that of the ET2.
b)....a heavy arm, when and only when, connected to a low compliance cartridge is a high performance, viable alternative
c)....the air bearing employed on these arms is effectively rigid at audio frequencies. So they should look elsewhere when looking for the cause of compromised note leading edge performance.

Richard Krebs
For a 8 gm cartridge of 30 cu I get horizontal resonance figures of around 4.7 hz and 4.2 hz for the ET2 and ET 2.5 respectively.

Thanks for this info Richard. We have always discussed just the spindle HZ resonant numbers before (5-6hz for ET2), and (2-3 for ET 2.5). As you point out this is just part of the equation. Understanding how they interact with the other “parts” in coming to an overall horizontal 4.7 and 4.2 for ET 2 and 2.5 is interesting using a 30 cu cartridge.

But we need to remember even if we all use the same 30cu cartridge, the numbers will be slightly different for each of us. We use different cartridge screws, #’s of lead weights, different positioning of the counterweight cap; a little higher, middle or a little lower; and finally the single double and triple leaf spring. Each one of these changes the parameters a little. So like the saying goes trust your ears.

The big consideration here for me is how the I Beam is affected. Dover mentioned the 2 – 6 hz variance in the I Beam from Bruce.

As soon as you change any variables in the I Beam Hz changes.

I also use a larger bolt to hold the lead weights.

So for tuning the ET2, ET2.5
Based on my observations/hearing. The tonearm has been designed for the first time user to let the weights fall at their natural location on the I Beam. This is what the manual says. This is how it is setup with most users and those that don’t like to tinker with it; and the sound achieved is very good and musical when setup properly. All the past reviews of the arm are probably based on this setup. The manual does also say to get the lead out to the end of the I beam if possible. For those that like to tune it even more – that is the one of the objectives of this thread.

Single, double and triple leaf springs that are not discussed in the manual but Bruce supports as we are still using a decoupled counterweight system.

Chris,

The thicker spring results in a higher resonance frequency. Thanks
Brucet

The thicker spring works better for lower compliance cartridges for me. But it raised the resonance frequency – not good. This is countered by getting the lead to the end.

Chris,

You always want the horizontal natural frequency of the counterweight to be less than the cartridge/arm resonance, this is the case 98% of the time.
The natural frequency of the I-beam/leaf spring depends on the thickness of the spring, the amount of weight, and where the weight is on the beam. The natural frequency goes down as the weight moves further out on the beam which is where we want it to be.
Brucet

If the sound is still not right with a double spring in your setup – drop down to the single leaf spring.

Aluminum Gooseneck on the ET 2.5.

A much tighter coupling at the arm tube and at the air bearing spindle inserts.

Tight enough that it requires effort to set Azimuth.

Eliminates the bolt that joins the carbon fibre armtube insert to the actual carbon fibre joint (Gooseneck).

A really good thing not only because of the eliminating a bolt, but because some over tighten it and others not enough. The 3 holes for leveling are gone. Not an issue with me as I always used the middle one. Much tighter overall. I like it !

Going through the cartridges with it.

A clearaudio virtuoso SS retip is on there now.
Cheers

Maths and Physics.

Stiffness
Many years ago I remember reading an audio magazine which tested the rigidity of the ET2 bearing. It may have been Martin Colloms, but I can't be sure. This was done, again from memory, where accelerometrs were used and a sweep frequency was applied to the spindle. The result showed a bearing that was stiff at audio frequencies.
This is explained by the design of the bearing (it's self centering characteristics) and its extremely high resonant frequency. Many times higher than the audio spectrum. Although the bearing uses air which we know to be compliant, at the frequencies of interest, the bearing medium is stiff.
I also show here a quote from an industrial air bearing manufacturer. While these a big load bearing devices, their design is virtually identical to the ET2

"Outstanding stiffness for small deflections Most engineers visualize an air bearing as being like a hovercraft, and they erroneously conclude that a bearing which floats on air cannot be very stiff. Actually these gas bearings are many times stiffer than a ball or roller bearing. Sapphire orifices within the bearing gap control the pressure in a film of air which is only 0.0003 inches thick. As a load is applied to displace the bearing rotor or slider, the gap decreases very slightly on one side, reducing the flow of air through the adjacent sapphire orifice. This results in a pressure increase in the gap on this side which pushes the rotor back to its original position. In essence, the air bearing is a servomechanism with closed loop control, and maintains a uniform gap in spite of external forces that may be applied. This results in bearing stiffness of millions of pounds per inch for small deflections. Stiffness is linear and does not change with temperature. In contrast, ball or roller bearings have almost no stiffness unless heavily preloaded. The stiffness of a ball bearing is not linear, and varies considerably with temperature."

Amplitude
A few weeks back I posted a transmissibility graph showing the effect of excitation frequencies at various multiples of the resonant frequency. This graph can be used to show relative resultant amplitudes for known resonant and excitation frequencies.
For a standard ET2 using in my case a Shelter Harmony, we get a resonant frequency of 8.4 hz. On my heavy arm, this frequency drops to 5.3 hz. If we take the lowest frequency of interest to be 20hz we get multipliers of res freq of 2.4 and 3.8 respectively.
By applying these multipliers to the graph we can see that the system which resonates at 8.4 hz shows a small rise in amplitude about 15%. If we now compare this with the 5.3 hz example we see a much smaller rise around 5%. We have to extrapolate this answer, since it is off the scale of the graph. In other words at audio frequencies the heavy arm produces less bass boost.
You can also see that the damping applied has very little effect on the resultant gain as the lines are trending together. This means that even if we factor in a higher resonant amplitude for the heavy arm, we can see that while it alters things slightly, it has minimal effect.

There is some merit in a discussion of what happens at sub sonic frequencies but the arm with the lower multiplier (lighter arm) will face problems sooner as we decend below audible frequencies.

As before these are all first principle discussions. It is what it sounds like that matters.

Chris.
Glad that you like the aluminium goose neck. I designed it to be as stiff as possible. The tighter fit into the wand and spindle is deliberate. Also it is made from the same grade of aluminium as the spindle, 6061 T6. This to minimise the different material count in the arm loop.