The problems of adding mass to air bearing tonearms. Here is Andy Payors ( Rockport 6000 ) view on it:
Andy Payor – Rockport 6000 Air Bearing Tonearm Designer - May 1996 review of the Rockport Series 6000.
"In linear trackers there is a big difference between the effective vertical and horizontal masses. Being a pivoted system in the vertical axis, a linear tracker's effective vertical mass is low because it consists of the relatively short armtube and cartridge. Horizontal mass is much larger: it includes the entire arm/sleeve assembly as well as the cartridge, all of which must be carried across the record and which do not benefit from being a pivoted system.
"Hang a small weight on the end of a spring and it bounces at a fairly high frequency over a short distance. Put a bigger weight on the spring and the rate of movement slows while the excursion length increases. The high mass of a linear-tracking arm in the horizontal axis can create a very nasty low-frequency resonance. The eccentricities due to the off-center pressing of virtually every LP made will excite this resonance as the system moves back and forth trying to track the shifting groove.
"In any arm/cartridge system, the arm should hold steady while the cantilever remains free to extract information from the groove. If the two were dancing partners, the cantilever would 'lead' and the arm would follow. In an undamped high-mass system the 'tail' (arm) begins to wag the dog (cantilever). Unwanted cantilever movement creates unwanted electrical output. In addition, any electrical output created with the coils uncentered in the magnetic gap is nonlinear, thus making it virtually impossible for the cartridge to act as a linear transducer, which is its job. Cantilevers can actually snap in undamped linear-tracking systems....In my opinion, a linear-tracking arm without damping is simply not viable if the goal is a 'reverse machine tool' accurately tracing what's in the groove."
This is precisely what I have been pointing out for the past 3 months. To recap the debate: 02-16-13: Dover
Richardkrebs
Re: your ET2 mods. Here are a few points for you to consider.
Richardkrebs post of 02-15-13
“I have a view on linear arms in that the rules for pivoted arms and effective horizontal mass do not apply. In fact I have added a lead slug inside the bearing spindle 25 mm long…
This combined with the fixed counterweight means that the arm is HEAVY in the horizontal plane.” This view is indeed strange. Many records are off centre. By increasing the horizontal mass of the arm significantly, when you play an eccentric record the increased resistance to motion from the additional mass will result in increased cantilever flex. On eccentric records your approach will result in phase anomalies during play back, increased record wear and probably cartridge damage in the long term. 02-23-13: Richardkrebs
Dover, for a given resonant system, all else being equal, addition of mass will lower the resonant frequency and reduce the amplitude of this resonance. ….Thou doth protest too much, methinks 03-12-13: Richardkrebs
Below this resonant frequency the cartridge is able to move the arms weight, start it and stop it, without cantilever deflection. I do not need to talk to cartridge manufacturers to confirm this. Do the math. 03-04-13: Richardkrebs
Your scaremongering may have dissuaded people from trying a simple reversible mod Andy Payor and Bruce Thigpen both disagree with adding mass. They both support my analysis that adding mass creates higher distortion, unwanted cantilever motion and non linear response from the cartridge. Please note the key points Andy Payor of Rockport makes. High horizontal effective mass results in: • The high mass of a linear-tracking arm in the horizontal axis can create a very nasty low-frequency resonance. • The eccentricities due to the off-center pressing of virtually every LP made will excite this resonance as the system moves back and forth trying to track the shifting groove. • In an undamped high-mass system the 'tail' (arm) begins to wag the dog (cantilever). Unwanted cantilever movement creates unwanted electrical output. In addition, any electrical output created with the coils uncentered in the magnetic gap is nonlinear, thus making it virtually impossible for the cartridge to act as a linear transducer, • Cantilevers can actually snap in undamped linear-tracking systems Andy Payors view of the world supports my argument for maintaining the ET2 as a low mass design and supports the use of “magnetic” damping. Andy Payors comments on air bearing tonearms are exactly the same as Bruce Thigpens. Bruce Thigpens patented decoupled counterweight design is specifically designed to deal with the unwanted nasty peak resonances inherent in linear tracking tonearms with a high horizontal effective mass. The suggestion of adding lead mass and removing the decoupling mechanism in the ET2 is inadvisable. It results in higher distortion and non linear response. Andy Payors endorsement of Bruce Thigpens low mass approach leads me to wonder why anyone would continue to advocate adding lead mass and removing the decoupling of the I beam from this sophisticated and ingenious high end tonearm. |
The writer, Dover, has written a great deal about air bearings lack of rigidity on this thread.
A few comments:
“In the Hifi News Review of the ET2 Martin Colloms concluded that the shape of the resonance passing through the air bearing remained intact.
This is not per se empirical proof that air bearings are rigid.”
Prove your assertion, thank you.
“Air bearings have compliance, and gimbal bearings can only be too tight (loaded) or too loose and can chatter.”
“The response above to my original post of 04-17-13 contains misinformation.
The comments plucked from the internet are irrelevant as they pertain to ball bearings and air bearings.”
Why is information on air bearings not relevant to discussion of air bearings?
“Unipivots are mechanically coupled, whereas an air bearing is not rigid and loses some of the leading edge.”
You have proof?
“So one could surmise that the Kuzma does have a stiffer bearing if you accept that Bruce Thigpen knows what he is talking about, which I do as he is well studied in Physics, Maths, Audiology and has been designing air bearings for some 30 years.”
Your statement regarding Bruce Thigpen is equivocal.
I suggest you contact Bruce Thigpen directly. Tell him you are the poster on Audiogon who has been promulgating the lack of rigidity of air bearings.
Ask him why he designed a floppy bearing and POST THE RESPONSE HERE unedited. Thank you. |
04-30-13: John47
The writer should get this, from Franc Kuzma:
'At hi-fi shows, we routinely ask people to pull or twist the Air Line tonearm on a Stabi Reference turntable. The whole suspended mass of 24kg (52.8 lbs) moves back and forth for 1/4!9 while the air bearing maintains zero friction! Most people are shocked.' John47 - thank you for this. It confirms that the ET2 should NOT have additional mass added to it by removing the decoupling and adding lead. The Kuzma bearing operates at about 60psi whereas the ET2 bearing operates at a much lower level. One cannot just increase the pressure; the manifold, airflow and bearing tube have to be designed specifically for the target operating pressures. Perhaps Ct0517 could test his ET2 with 24kg on the end of it. Eminent Technology have 3 manifolds available - The original low pressure - The original high pressure - A large spindle high pressure Increasing the pressure generally increases the stiffness.
Eminent Technology website
ET II Large Diameter High Pressure Manifold - This new manifold is a direct replacement for the original high pressure manifold. You just remove the old spindle and push the old manifold out of the base and then insert the new manifold into the base and slip in the new, larger and heavier spindle. The new manifold allows the spindle, which is suspended on the air bearing, to be increased in diameter by about ¼th of an inch. Now ¼th of an inch may not sound like much, but it is the surface area of the spindle within the manifold that helps determine the stability of the bearing. The surface area of the new bearing is about 25% larger than the surface area of the old bearing, plus the tolerances are closer than in the original high pressure manifold. This makes for a much stiffer bearing.
These comments from Bruce Thigpen do not agree with the view opined in the following post 04-23-13: Richardkrebs
Although the bearing uses air which we know to be compliant, at the frequencies of interest, the bearing medium is stiff. So one could surmise that the Kuzma does have a stiffer bearing if you accept that Bruce Thigpen knows what he is talking about, which I do as he is well studied in Physics, Maths, Audiology and has been designing air bearings for some 30 years. Eminent are in the process of designing a new higher pressure bearing
Eminent Technology website
We are also developing a very high pressure bearing for the ET 2.5 which will operate between 20 and 80 psi. Please contact Eminent Technology if you have any questions.
The main advantage of the ET2 over the Kuzma is the low horizontal inertia and split resonance tuning capability due to the decoupled counterweight assembly. These features ensure there is no bass hump and provides superior tracking of the groove. Superior tracking will preserve the harmonic structure of notes. A good example of this is the test results that Frogman posted
03-23-13: Frogman
For instance, I am not yet convinced entirely that IN MY SYSTEM, going for the lightest weight/mass possible is the way to go. Yet, and speaking of loosening the laces, I decoupled (loosened) the I-beam yesterday, and lo-and-behold, on Donald Fagen's new release "Sunken Condos", what had previously been little more than amorphous low frequency energy suddenly became notes that I could discern the pitch of; completely the opposite of what I expected given my experience (extensive) experimenting with springs of different compliances (single, double, etc.), and the reason I had not tried it yet.
Bruce Thigpen confirms the problems created by increasing the horizontal inertia.
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
This has been the thrust of my posts over the past few months – adding lead and removing the decoupled counterweight takes away to benefits of the ET2 split resonance low mass design, causes an unnatural lift in the bottom end and increases distortion. These suggested modifications eliminate the main benefits of the ET2 design. Frogman, Slaw, Ct0517 and my own testing concurs with this. We have all achieved superior results with the correct tuning of the decoupled counterweight I beam. |
Hi Manitunc
You can also find the measurements for VPI and SOTA templates in the online ET2 manual - Part two on pages 62 and 63 at the back. Drilling even the one small hole that the ET2 needs, in a nice plinth ranks up there as probably one of the most stressful things I have done in this hobby. If using removable armboards ? I usually make a test one out of some material to practice with. Welcome to the thread. |
|
does anyone know if there is a downloadable mounting template for the ET@. I have two of them, an I want to mount it on my custom Lenco, but I'd prefer not to start dirlling unless I know for sure what I am doing. I have dowloaded the manual, but it really doesnt give enough accurate info on mounting, mostly because you can buy a metal template.
anyone have any info? |
Dover wrote:
"This is nonsense Richard. Your comments that the air bearing is rigid defies physics. Have you heard of compressed air. You can get 2300l of air into a dive bottle with an internal volume of 11 litres. Try that with metal.
Why not try to compress 1 litre of metal into a 50ml can at audio frequencies. According to your thinking this is possible.
Do you get any of this?"
The writer should get this, from Franc Kuzma:
'At hi-fi shows, we routinely ask people to pull or twist the Air Line tonearm on a Stabi Reference turntable. The whole suspended mass of 24kg (52.8 lbs) moves back and forth for 1/4!9 while the air bearing maintains zero friction! Most people are shocked.' |
Chris.
Good to read your findings on the gooseneck. They parallel what I heard when making the change here. You can expect more of the same when we find a way to bypass the o'rings in the manifold, along with a satisfying jump in dynamic contrast and low level detail. |
Issues Created When Adding Lead Mass and Removing the Decoupling of the I Beam on the ET2 04-21-13: Richardkrebs
b)....a heavy arm, when and only when, connected to a low compliance cartridge is a high performance, viable alternative This statement is not correct within the context of the ET2. Adding Lead to the arm increases the horizontal mass. Removing the decoupling on the I Beam increases the horizontal mass. The ET2 is designed with a target horizontal mass to be used in conjunction with a decoupled I Beam & Counterweight. Increasing the horizontal mass increases distortion due to the additional side loads on the cantilever & tracking is compromised. Increasing the horizontal mass creates a large peak resonance in the bass that also affects tracking and increases distortion. 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 When you add mass and remove the decoupling how big is the resonance in the bass? Bruce Thigpen has measured up to a 6-12db lift in the bass when testing the removal of the decoupling from the I beam 04-23-13: Richardkrebs
Maths and Physics.
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 explained earlier in this thread the maths quoted above is for a single pendulum. The calculations above are based on a singular pendulum. The calculations above do not take into account the fact that the ET2 arm & cartridge have multiple pendulum effects in the horizontal mode – - the cartridge cantilever swings around the record pivoting at the stylus tip - the cartridge cantilever swings around the cartridge at the suspension end - the I beam This is why when Bruce Thigpen measures the impact of coupling the I beam he can measure up to a 6-12db lift in the bass. The calculated numbers in the above post are are theoretical calculations for a single pendulum, which does not apply. No actual test results have been provided that support these numbers and conclusions. Does this resonant peak really matter if it is below the audio spectrum ? 04-27-13: Ct0517
I usually hear only about audio designers trying to come below the audio spectrum – especially with a TT setup ?
That is what the conversations have been based on here as well ? 2hz – 6 or 7 hz. . The fundamental resonance is created by the combination of the compliance/mass of the cartridge vs the effective mass of the arm. Tonearm designers try to keep this as low as possible and minimize its amplitude. The peak rise in bass response generated by the arm/cartridge does not rise and fall at one frequency. The peak resonance has a spread either side of that calculated peak resonant point. Again I need to reiterate that Bruce has actually measured bass lifts of 6-12db when removing the decoupling. Even if one ( wrongly ) assumed this resonance has no effect because it is out of the audio band, one would be wrong because the bass lift ( nasty peak resonance ) can impact tracking adversely. This is why adding lead mass and removing the decoupling as advocated is wrong. Not only is it increasing inertia and side loads on the cartridge, it is also putting a lift in the bass frequency by removing the split resonance functionality that this arm uses to give a flat response. Adding lead mass and removing the decoupling will increase cantilever flex and tracking distortion. |
Bearing Stiffness – Naim Aro vs ET2 04-21-13: Richardkrebs
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. 04-16-13: Richardkrebs
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. 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. 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 the addition of lead mass or removal of the decoupling. 04-23-13: Richardkrebs
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." The response above to my original post of 04-17-13 contains misinformation. The comments plucked from the internet are irrelevant as they pertain to ball bearings and air bearings. They were copied from the following website http://www.space-electronics.com/Products/air_bearings.phpThe Naim unipivot does not use ball bearings. The Naim Aro is mechanically grounded whereas the air bearing is not. Unipivots are the most rigid coupling you can get in a tonearm. Air bearings have compliance and gimbal bearings can only be too tight (loaded) or too loose and can chatter. In the Hifi News Review of the ET2 Martin Colloms concluded that the shape of the resonance passing through the air bearing remained intact. This is not per se empirical proof that air bearings are rigid. I note that most users of the ET2 have increased the air pressure up to around 19psi and have reported improvements to the sound as the pressure is increased. When the operating air pressure is increased, the following operating parameters are altered - the Q of the system, the dynamic stiffness of the bearing, the resonance frequency of the air bearing itself, the shearing forces are changed. All of these changes will of course be in themselves be difficult to calculate as the results will vary depending on the resonances in the I beam and cartridge and masses involved. This is precisely why Bruce Thigpen backs his physics and maths up with extensive testing. |
04-29-13: Ct0517
04-27-13: Dover
.....dont be embarrassed about using spotify, I've heard spotify streamed through an Ipad.........
Dover – if you know Spotify then you would know its not available in Canada. Have never heard it. My post on that article had everything to do with music itself – regardless of format and nothing to do with the equipment. It appears my post was misunderstood by you ? and maybe others so the reason for my post.
Dover –in this picture is a mechanically grounded unipivot. Please note the way it has been setup. What do you think happens to the sound when it is set up this way ?
Here is another
example
A little more extreme ?
Ct0517 (System | Reviews | Threads | Answers | This Thread) Ct0517, Spotify - Ct0517 since you mentioned this I thought I should share my experience. Digital can be a very useful tool to benchmark our analogue front ends to, particlularly in terms of speed, timing, transparency and identifying colourations in our systems. It can provide a useful benchmark due to its consistency whilst we tune our analogue front ends. That is not a value judgment on quality - it is the consistency that is of value. Nevertheless, I have heard Ipad/DAC front ends sound better than poorly set up or badly modified analogue TT's. I was unaware it is not available in Canada as I dont live there. Mechanical Grounding - Please explain your point. When I use the term mechanical grounding it was in the context of the bearing itself, not how the arm is mounted. Naim Aro tonearm
By Markus Sauer • Posted: Jun 5, 1995 • Published: Jun 5, 1993
The bearing is the ARO's stroke of genius. In other unipivots, a sharp pin is mounted to the turntable and the arm carries a cup which sits atop the pivot point. The ARO's arm carries the sharp tip, resting this atop a stationary cup: a true mechanical ground, and the only spiked tonearm I know of!
I've had less experience with the Eminent Technology ET 2 and Graham 1.5t than with the other two arms, and so don't want to make too strong a statement, but I don't think they can hold a candle to the ARO in the boogie department. The ET 2, on the other hand, presents an even more spacious soundstage and possibly even lower distortion, due to its superior geometrical accuracy. There are clearly pro's and con's with any piece of equipment. In this case of the Naim ARO and ET2 we are trading off the more accurate preservation of the leading edge from the mechanical grounding of the Naim bearing for the superior soundstaging and lower distortion of the ET2 from the tangential geometry. This notwithstanding that adding mass and removing the decoupling from the I beam and counterweight assembly will of course promote distortion, negating the benefits that are inherent in the ET2 as has been explained by the designer Bruce Thigpen. |
Some Gooseneck Impressions in my system/room.
First a reference point.
You can go listen to a group/band in the same location for two different days. They will sound different for each performance. No performance is the same. They are humans after all not robots. Sometimes you walk away from the performance with a smile on your face a lift in your step. Other days you are neutral; walk away thinking not about the performance but where you are headed next. This could be the result imo - of how your day went or maybe how the day went for those musicians. Did they gel or not ? I like my music to give me a lift, give me a smile. Its a stress reliever. When we add or change gear or tweak our gear it needs to go forward for us. This is a personal thing based on our own preferences. Its doesn’t always go forward as we all know. So.
In general a tighter sound and transients faster. More lively. Pace is quicker.
The Carbon Fibre (CF) gooseneck sounds a little plusher and velvety in comparison in my system. Bass notes last a little longer with the CF. This in turn depending on your setup can fill in the sound or smear the sound if too much bass – in the later case it makes the music sound slower for me.
The aluminum goose neck increases the clearness of the individual bass notes themselves; rather than a note mixing with another I now able to better hear the end of individual bass notes clearer. It was really good before - its just better now for me.
A bigger surprise to me. My room monitors were designed to be used in active mode with a Bass Alignment Filter (BAF). This allows the monitors to go down to 20 hz in a room that normally would not allow this much extension due to room constraints. I own a couple version of these BAF’s. This gooseneck tweak is a big enough tweak in my room that it allows me to better differentiate between the BAF’s and their engineering differences.
So many ways to tweak our sound from the source to speakers.
I am very happy with the sound and even more impressed with the quality of this piece.
Cheers |
04-27-13: Dover
.....dont be embarrassed about using spotify, I've heard spotify streamed through an Ipad......... Dover – if you know Spotify then you would know its not available in Canada. Have never heard it. My post on that article had everything to do with music itself – regardless of format and nothing to do with the equipment. It appears my post was misunderstood by you ? and maybe others so the reason for my post. Dover –in this picture is a mechanically grounded unipivot. Please note the way it has been setup. What do you think happens to the sound when it is set up this way ? Here is another exampleA little more extreme ? |
|
|
Dover – I enjoyed your poem :^)
It reminded me of someone else on this thread whose moniker implies the test of time.
I am terrible at poems. I wrote one for a girl a long time ago and gave it to her.
She broke up with me the next day.
It left a bad feeling. Maybe I should try again... |
Air Bearing Stiffness
Richardkrebs
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."
Richard - thanks for providing this info - the part that hits home with me. “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 usually hear only about audio designers trying to come below the audio spectrum – especially with a TT setup ? That is what the conversations have been based on here as well ? 2hz – 6 or 7 hz. This is truly outside of the box. Dover mentioned somewhere on this thread a while back that testing of the resonances with the ET2 seems to just pass through it ? Dover - was this the same study? Maybe the test gear was not good enough to capture this info. I mean - its parameters setup for human hearing. "Many times higher than the audio spectrum" I guess this explains why my dog does not start howling when I play music. Its beyond him as well. ... Regarding leading note edge performance. My reference in my room are master tape dubs. No issues here with the air bearing. |
Why your Brain Craves Music A warning up front – the author does not care whether we use a spring or not. And his main music source is Spotify. By Dr. Mercola If you’re a music lover, you already know that turning on the tunes can help calm your nerves, make stress disappear, pump up your energy level during a workout, bring back old memories, as well as prompt countless other emotions too varied to list. Even if you’re not a music aficionado, per se, there are compelling reasons why you may want to become one, which were recently revealed by a series of new research. Music Prompts Numerous Brain Changes Linked to Emotions and Abstract Decision Making When you listen to music, much more is happening in your body than simple auditory processing. Music triggers activity in the nucleus accumbens, a part of your brain that releases the feel-good chemical dopamine and is involved in forming expectations. At the same time, the amygdala, which is involved in processing emotion, and the prefrontal cortex, which makes possible abstract decision-making, are also activated, according to new research published in the journal Science.1 Based on the brain activity in certain regions, especially the nucleus accumbens, captured by an fMRI imager while participants listened to music, the researchers could predict how much money the listeners were willing to spend on previously unheard music. As you might suspect, songs that triggered activity in the emotional and intellectual areas of the brain demanded a higher price. Interestingly, the study’s lead author noted that your brain learns how to predict how different pieces of music will unfold using pattern recognition and prediction, skills that may have been key to our evolutionary progress. Time reported:2 “These predictions are culture-dependent and based on experience: someone raised on rock or Western classical music won’t be able to predict the course of an Indian raga, for example, and vice versa. But if a piece develops in a way that’s both slightly novel and still in line with our brain’s prediction, we tend to like it a lot. And that, says [lead researcher] Salimpoor, ‘is because we’ve made a kind of intellectual conquest.’ Music may, in other words, tap into a brain mechanism that was key to our evolutionary progress. The ability to recognize patterns and generalize from experience, to predict what’s likely to happen in the future — in short, the ability to imagine — is something humans do far better than any other animals. It’s what allowed us (aided by the far less glamorous opposable thumb) to take over the world.” To read more |
|
Ok I think my eyes are doing funny things. I admit I saw and read a couple posts now in the last couple of weeks here - only to see them disappear? I have heard similar things about this phenomena on the MM thread. But there the posts never made it.
I know we are all big boys here and can handle whatever controversial topic comes up but maybe we have reached tolerance levels with the moderator? I think we still can have robust debate. Maybe we just need to be a little careful with some of the words we use. Just a thought.
Or maybe it is my eyes and I should switch to South African wines from Australian for a while? Good thing this hobby is based on hear and feel.
Cheers |
Richardkrebs
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. A correction to my earlier post regarding the make up of the ET gooseneck. The ET armtube insert is aluminum as well. The joint itself is Carbon Fibre. Sorry for the error. Both Richard's and Eminent Technology versions can be seen here |
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. |
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. |
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 |
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. |
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. |
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 |
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. |
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. |
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 |
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. |
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. |
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 . |
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. |
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 |
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. |
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. |
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 |
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? |
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. |
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 |
John47: What? I assume you are making a statement. Can you tell me what or how it pertains to this thread? Thank you. |
Frogman: Can you explain the outer wire (it seems) that you have wraped around your armwand? |
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 |
A hint to the ET1/ET2 trivia questions. The answers can be found within here but only for a few more days. |
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 ? |
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. |
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. |
Not an audiophile! Never mind.
But I do know what 'diatribe' means:
"A forceful and bitter verbal attack against someone or something." |
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 |
