Eminent Technology Two tonearm
The Technical Background
Bruce Thigpen was one of the original developers of the air-bearing arm; at the same time he developed an air-bearing turntable marketed by Colony and later taken up by Maplenoll (footnote 1). He sought to create a frictionless straightline, with nearly perfect geometry, requiring no servomechanisms, decoupled from the turntable and its acoustic breakthrough problems, and inherently low in resonance.
Like many inventors, however, Bruce had serious problems getting the capital to put his ideas into the form of a product, particularly in a form with good ergonomics and low risk to the cartridge. The Eminent Technology One, his first tonearm, worked well sonically, but the arm was still not a finished consumer product. The tonearm lift was inadequate, and a minor mistake by the user could slam a cartridge down to its doom.
The Eminent Technology Two is quite different. A fully finished product which any consumer will find safe and easy to use, it has fully functional and easy-to-operate adjustments in each of the following important areas:
A system for changing cartridges that quickly locks tonearm tubes in and out, with a separate, unpluggable signal connection. The setup gives far more repeatable and exact results than even the best two-pin removable headshells, although changing the arm tube may require slight re-leveling of the arm.
Arm tubes that are tapered and internally damped to minimize resonance.
An excellent VTA/SRA setup, easy to adjust during record playing, with a precise vertical scale for repeatable VTA.
A very good and completely reliable cueing lift, with adjustable range and height.
Removable arm tubes on which azimuth and overhang remain set up; this makes the Eminent Technology Two one of the few tonearms I know of (footnote 2) in which the audiophile can rapidly change cartridges while maintaining precise azimuth and overhang.
Tonearm and tonearm pivot height are fully adjustable and can be measured precisely.
Horizontal and vertical balance can be precisely adjusted.
Tracking force and tonearm mass are adjustable using four separate lead weights: a master weight of 15 grams and three auxiliary weights of 15, 5, and 5 grams, providing a range of 1540 grams in 5-gram steps. A heavy weight can be put near the fulcrum for high-compliance cartridges, and a light weight can be placed away from the fulcrum for low compliance cartridges. The whole system is designed to minimize resonance as felt by the cartridge.
The counterweight system is decoupled on a damped leaf spring that permits horizontal but not vertical motion. The system has a graduated millimeter scale; various weight packs, for given cartridges, can be quickly returned to the proper tracking setting.
Once mounted, the arm can be precisely leveled relative to the turntable. In fact, almost everything seems adjustable with a 3/32" allen wrench.
Set-up is not easy, but a precision jig is available for dealer use, and is available at a reasonable cost to audiophiles (around $50). This jig allows very easy set-up and ensures excellent alignmentin fact, probably more precise alignment than is possible with any other tonearm. The standard jig is suitable for the SOTA, VPI, Linn, Goldmund, and most other leading turntables. A special mounting bar and alignment jig are available for Oracle owners.
About all that I can add by way of tips to anyone using this alignment and set-up jig is that the arm base couples to the tonearm mounting board on tiptoes. It is easy to secure the base too tightly to a plastic mounting board, which will slightly deform the base under each tiptoe; at that point, it can no longer be moved to just the ideal position (if you don't already have it). You should set up the arm very carefully with the tiptoes just touching the turntable's tonearm board. When everything is correct, secure the arm so the tiptoes are firmly making contact. Do not overtighten the arm's mounting post to the turntable; a good solid fit will work fine.
Leveling is critical, and necessary for both arm and turntable. The last thing a straightline tonearm needs is sidethrust, particularly that provided by gravity. The tonearm wire must also be carefully dressed for freedom of movement, especially at the end of the record.
I'd also be careful about air pump and filter placement. They are relatively quiet, and free of the hiccups and burps that affect the pumps of other air-bearing designs, but the pump is still noisy enough to require placement in a cabinet (or in another room). You will have to ensure that the hose from pump to arm remains free of external or internal obstructions. Just as with the SOTA Star Sapphire, the tweaker who cuts off his air supply is likely to strangle his system.
Further, the pump has to be hooked up to some switchable outlet on your system since it lacks a switch; it should not be left running indefinitely. Otherwise you might try to track a record with the air bearing airlessnot good for the health of your records.
Technology and Sound
The sound of the Eminent Technology Two is fully state-of-the-art. With soloists and small musical groups, the Two is better than the One, and better than any arm I've encountered, including the far more expensive Goldmund and Fletcher. I know of no tonearm at any price that provides more detail, and seems as free of coloration.
Tonearm evaluation is extraordinarily difficult. While Peter Moncrieff and Martin Colloms have made some progress in the area of measurements, I still find little positive correlation between their resonance graphs and the resulting sound of the tonearmprovided that the basic design is good to start with.
If anything, the tests that Martin Colloms has published in Hi Fi News and Hi Fi Choice, which are unquestionably state-of-the-art in this area, indicate why tonearms are so hard to review. The complex resonance differences revealed in arm after arm must color the sound, but in what ways? Compare the review of the new SME arm in Hi Fi Choice No.40 to other reviews in the same issueit is impossible to tell whether the result is good or bad on the basis of the data provided. Even the review seems ambiguous as to whether the SME is good because of the measurement, or in spite of it.
The same is true of trying to correlate tonearm sound to bearing design. Designers have shown during the last two years that it is possible to get excellent sound from a very wide range of designs.
One of the saddest comments on British manufacturing is that the reviewer's "creampuff" sample of the more expensive British arms is often praised for its tight and expensive bearings. Unfortunately, the product that goes to audiophiles all too often has slightly sticky, or maladjusted, bearings, which makes me doubt whether the particular results achieved by reviewers will ever be duplicated in the homes of audiophiles. For some reason, the British tend toward overtightening, and the Japanese toward undertightening. I regret to say that the Alphason and Linns are the only British arms I have seen in recent years with consistent quality control, although I should note that the Syrinx has been improved and may now well prove a worthy competitor.
Tapping the tonearm with a screwdriver or pencil and listening for a hollow sound or resonance is a useful test. I agree that most pivoting arms that sound inert when tapped are better than those which do not. I cannot, however, get terribly excited about this test; a large number of arms that met this test still sounded mediocre, and some hollow-sounding arms reproduced music quite well.
As Martin Colloms has pointed out in his tonearm reviews, the situation is further complicated by the fact that no tonearm/turntable combination can provide fully accurate bass. From record cutting to final reproduction at the speaker, there are normally at least twelve mechanical and electrical filters affecting the bass, and arm performance here is remarkably sensitive to the way the arm is mounted to the turntable. Just as changing turntable mats can change the sound of turntables, changing mounting boards from wood to plastic to metal can lead to major variations in bass from tonearms.
As for low frequency resonance, I cannot quarrel with the idea that it should be kept at 912Hz, and that cartridge compliance should be matched to tonearm mass. The problem is that few tonearm and cartridge combinations produce major problems in this area, provided some attention is paid to the counterweights or other adjustments used. Further, I am uneasy about this criterion because it ignores the fact that cartridge/tonearm interaction is often very sensitive to vertical and horizontal mass: the right mass relationship affects the music far more than it affects low frequency resonance.
It should be clear that reviewers are ultimately stuck with their own ears. Given this preamble, it should also be clear why I am not going to praise the Eminent Technology Two with long discussion of the merits of straightline tracking or air-bearing design.
My praise will instead focus on the fact that, after several months of comparative listening, the Eminent Technology has always provided enjoyable music with more natural detail than provided by any competing arm. It has an extraordinarily live and open soundstage, but doesn't change the soundstage in ways I would not expect from a given cartridge, tonearm, electronics, and speaker. The Eminent Technology is consistent, convincing, natural, and musically pleasing.
If it has any sonic limitation, it may lie in the deep bass, which is provided by the very best pivoting arms more powerfully and accurately, and in the feeling they give of more powerful musical dynamics. This is the only area where the Eminent Technology Two has ever raised any serious questions regarding its ability to outperform or equal any arm I have heard, but this area is so controversialas to what is rightthat I can do little more than raise the issue.
My only other caveats lie in the fact that its general superiority over the best competition I've heard is less apparent in reproducing large orchestral music than solo and small musical groups. Other arms may also produce a better interface with a given cartridge. Nevertheless, most cartridges will not perform as well with any given competing tonearm as with the Eminent Technology.
The Usual Reviewer Complaints and Quibbles
Is the Eminent Technology Two technically and ergonomically perfect? Hell, no! Nothing is. The arm's lateral mass is a potential problem under one rather weird circumstance. If you happen to be heavily into 45rpm 12" singles, the combination of a grossly eccentric record (more than 1/8" off-center) and a high-compliance cartridge could cause more deflection in the groove than with competing tonearms. For most audiophiles, this will be about as serious a risk as the chance of the turntable being hit by a meteor, but the problem is there.
The arm does not flip back off the record like the Souther, to allow easy change of records. Bruce could also do a few things more to ensure that the audiophile will get the best from his arm. You really do need to buy the setup jig to get an ideal setup. And, despite how essential it is with an arm requiring such fine adjustment, there is no instruction manual as of this writing.
The arm's effective mass may be a little too high for some high-compliance moving magnets. As for other cartridges, I would like to see very specific suggestions from the manufacturer as to the proper combination and location of weights for a given cartridge. The arm is now too adjustable for the consumer or dealer who does not measure low frequency resonance, and I still do not fully understand how the location of the counterweight package best interacts with a given type and compliance of cartridge.
The tonearm wiring termination may also need improvement. The present RCA jack mounting plate works, but you have to solder the tonearm wires to it, and mounting the plate can mean the equivalent of hardwiring the arm to a turntable. Finally, I suspect that Eminent Technology may ultimately have to manufacture a mounting board for some of the best turntables that provides precisely the right sonic interface between arm and board, or persuade the turntable manufacturers to do so. (Such an accessory would probably benefit any top quality arm.)
I should stress that in using the Eminent Technology Two to recalibrate my perceptions of past arms, I am not recommending that you should rush out and sell your existing top-quality arm. Nor would I say that the Eminent Technology Two lacks competition. I will be using the Eminent Technology Two as a reference because I think it is that good, and because I feel it is that neutral in terms of turntable and cartridge compatibility. I have not heard every top arm, however, and hope the above mini-reviews indicate that the competition is still very close.
In fact, today's best tonearms are so good, and offer so much variety, that any given audiophile or reviewer could easily prefer several of the above arms to the Eminent Technology Two. Further, I'd put money into a better cartridge, turntable, etc., long before I rushed out to exchange a top-quality competing arm for the Eminent Technology. That said, Bruce Thigpen and Edison Price have done a damn good job! The Eminent Technology Two is certain to be a highly popular product with even the most demanding audiophiles.Anthony H. Cordesman
Footnote 1: A complete description (and cover drawing) of the Colony Air Bearing Turntable and Arm is found in Vol.5 No.5.
Footnote 2: The others are the Micro Seiki and the Dennesen, this information graciously supplied by Eminent Technology (not, apparently, in the interests of vicious competition).Larry Archibald