Listening #140

Has it really been 30 years since an engineer named William H. Firebaugh unleashed on the audio world his radical and decidedly affordable Well Tempered Arm? (footnote 1) Indeed it has—and today, at 82, Bill Firebaugh seems busier than ever, with so many irons in the fire that he's been forced to give up the noble game of golf—an irony, as you'll see in a moment.

Firebaugh started down this road in the 1970s, while working at Ford Aerospace. "That was the time when FFT analyzers were appearing on the scene," he says. "We used a lot of Brüel & Kjaer gear in our work, so we received all of the technical papers that Brüel & Kjaer published. That was the only reason I ever saw a paper of theirs titled 'Audible Effects of Mechanical Resonances in Turntables,' by Poul Ladegaard. And that set me off. Once I read that, I knew what the issues were—and are."

The paper, which Ladegaard presented at the 1977 AES convention, in New York City, describes the audible effects of various resonances within the typical record player—including, of course, the fundamental resonance exhibited by the combination of tonearm and phono cartridge, as determined by the combined mass of both and the compliance of the latter. But Ladegaard's research went further, taking into account such variables as platter-bearing noise, record-mat compliance, and motor irregularities. Consequently, even though Firebaugh's first impulse was to make a tonearm with resonance-free bearings and correct damping, he came to see that the real goal in phonography was to design a tonearm and turntable that could function together as a system.

Firebaugh's resonance-free tonearm bearing turned out to be no bearing at all, at least not in the traditional sense: Famously, the Well Tempered Arm was suspended by two strands of nylon monofilament, thus sidestepping all concerns over bearing clearances and chatter. A coin-shaped damping paddle, fastened to the arm just below its pivot point, was horizontally submerged in a fixed tub of silicone fluid. As the arm moved laterally, the thin paddle knifed easily through the honey-thick liquid; however, it encountered a far greater degree of resistance in the vertical plane, thus introducing a desirable degree of damping.

Firebaugh's sophomore product, the Well Tempered Turntable, proved no less original, boasting a platter bearing of particular ingenuity. Unlike most of his contemporaries, Firebaugh saw the quest for an ideal bearing not as an exercise in making ever-thicker spindles or ever-more-exotic "jeweled" thrust plates to support that spindle, but one in which noise and resonant sidebands were diminished through, again, the elimination of clearances: The nylon bore of Firebaugh's bearing well was well bigger than the steel spindle that turned within it, the latter held perfectly upright only when "loaded" by the tension from the motor-drive pulley and drive belt. Thus pulled into alignment, the shaft contacted the well at only five points: one Delrin pad serving as a thrust plate, and four others describing the sleeve.

Secondarily, by lubricating his zero-clearance bearing with a bath of thick silicone, Firebaugh endowed it with some degree of rotational damping: an element of resistance that also served to maximize torque. We hadn't seen that idea here since 1957, when the last of Garrard's greased-bearing 301 motor units rolled off the assembly line.

A man of distinctive bearing
Today, most of the ideas behind the Well Tempered Arm and Turntable remain in the company's current models, but the designs are executed differently—as I recently observed while spending a few weeks with one of the latest products of Well Tempered Lab: the Amadeus Mk.II record player ($2850 for turntable with tonearm, footnote 2).

The latest version of Bill Firebaugh's tonearm, the Symmetrex, retains the monofilament bearing, but adds a few twists of its own—literally, in the case of WTL's current approach to antiskating. The Symmetrex hangs by a single nylon strand, looped around a grooved steel collar that rides along a height-adjustable steel suspension rod. A rubber grommet ensures a tight fit between collar and rod, while allowing the collar to be rotated to adjust azimuth.

During setup, that bearing collar is also adjusted so that the arm is suspended precisely above a height-adjustable damping cup, in which rides not a paddle but a hemispherical segment of a golf ball. Although Bill Firebaugh makes no such claims—he says, with characteristic modesty, that the golf-ball thing occurred to him early one morning during his pre-coffee "zombieness"—it seems to me that the roundness of the ball, combined with the adjustability of the damping cup's height, enables a far wider range of damping settings than was possible with earlier WTAs.

814listen.armcup.jpg

The effective length of the tonearm is greater than average, at 10.5". Its modest aluminum cartridge mount is fixed in place at an offset angle of 19°, and there are no provisions for overhang adjustment—a fact noted in the comprehensive owner's manual: "Some alignment protractors may well disagree. However, the Well Tempered Lab stands by their convictions."

For its part, the Amadeus Mk.II turntable seems to have even less in common with its own progenitor, the original Well Tempered Turntable. In fact, the new model differs considerably from the similarly priced Well Tempered Record Player, which I wrote about in my November 2006 column. Chief among those differences is the manner in which Bill Firebaugh executes his zero-clearance main bearing: The polished-steel bearing axle is now pointed rather than flat-bottomed, and the Delrin nubs have been dispensed with. In their place is a polyethylene thrust pad with a 1/8" dimple at its center, and a Delrin collar near the top of the well, with a triangular cutout at its center. The bearing well is fastened to the plinth in such a way that one corner of the triangle points directly toward the motor pulley; for that reason, and because the bearing axle is considerably smaller than the triangular hole (the former is 0.285" in diameter, while the sides of the latter are approximately 0.4" each), the drive belt tends, under load, to pull the bearing axle upright, with its pointed bottom located in the thrust-plate dimple, and its shaft snugged into a corner of the triangular cutout. (Thus I imagine the new one could be called a three-point, zero-clearance bearing.)

For this bearing Firebaugh has dispensed with the thick oil and, with it, the old bearing's rotational damping. He says he recently discovered, more or less by accident, that the Amadeus Mk.II bearing can run for at least seven weeks, 24 hours a day, without apparent damage. "It works great without any lubricant," Firebaugh says before adding, with a laugh, "But, being kind of chicken, I recommend using oil." A generous vial of bearing oil is supplied with the Amadeus, and the owner's manual suggests that any synthetic motor oil with a viscosity of between 5W and 50W will also work just fine.

814listen.bearing.jpg

The Amadeus Mk.II's platter is considerably different from the one supplied with the Well Tempered Record Player of eight years ago. The earlier platter, designed to be used without a mat, had a screw-on clamp and a drastically concave top, the combination of which rendered the playing surfaces of LPs distinctly nonlevel. Thankfully, the new acrylic platter is as flat as Elizabeth McGovern's delivery—a commendable quality where record platters and platter mats are concerned—and is machined to a diameter of 13", presumably to enhance speed stability. An 11.25"-diameter foam mat is supplied as standard.

An even more visible difference is the Amadeus Mk.II's onboard DC motor, earlier WTL turntables having been noted for their outboard motor pods. The new motor is tiny compared to that of its WTL predecessors—its plastic body is less than 1" in diameter—and it's surrounded by a thick foam damping ring, in addition to being fastened to a compliantly isolated mounting plate. The molded pulley is also tiny, and the motor's servo-drive electronics are mounted inside the plinth, which is made of a double layer of MDF finished in textured black paint. (Also unlike the earlier Well Tempered Record Player, there appears to be no layer of compliant damping material between the layers of fiberboard.) A tiny trim pot, accessible through an opening on the plinth's back edge, allows the user to fine-tune the motor's running speed, a chore for which a nice, full-size strobe disc is supplied.



Footnote 1: The Well Tempered Tonearm was first reviewed in Stereophile by J. Gordon Holt, in 1984 (Vol.7 No.8). An interview with Bill Firebaugh can be found here.

Footnote 2: Well Tempered Lab, PO Box 2650, Christchurch, New Zealand. Tel: (64) 3-379-0743. Web: www.welltemperedlab.net. US distributor: Mike Pranka/Toffco, Tel: (314) 454-9966.

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btrussell44's picture

Art - thank-you very much for your esteemed opinion on a fairly new member of the new, redesigned generation of Well-Tempered turntables.

I was especially interested and gratified to learn from your comments that the Amadeus MkII apparently has much (or all) of the musicality of one of the old generation 'tables you reviewed several years ago. I'm pleased that this superior 'momentum and flow' character hasn't been lost despite all of the design changes.

I was also very interested to learn your perspective on the controversial aspect of Well-Tempered's tonearm's unique geometry.

My keen interest in the matter of tonearm geometry has come about because my experiences with the original Well Tempered Amadeus model has me mystified. I bought my Amadeus new a little more than a year ago. Initially upon setting up my turntable, I installed a brand-new Dynavector MC cartridge. But music played with my new cartridge suffered from severe distortion, especially on amplitude peaks. After a great deal of investigation into setup it seemed unlikely that my problem was related to a manufacturing defect, so I concluded that the cause of the distortion must be the cartridge. To test my theory I installed an Audio-Technica MM cartridge that I had used successfully on another turntable. But mounted on my Amadeus it too suffered from distortion - fortunately, a good deal less serious than the Dynavector - but still unacceptably high. One thing led to another, and after a great deal of sleuthing and several emails back and forth to the Canadian Distributor I learned that my tonearm's effective length (EL) - I measured mine to be at 260 mm - was almost a half-inch too short. The distributor assured me that the proper EL for my model's tonearm was 270mm (he confirmed this by measuring some that were set up in his showroom). I was impatient, so rather than ship my tonearm to the distributor to be repaired, I changed my tonearm's EL by sliding the tonearm wand inside its rubber collar (located within the silver flange on top of the golf ball) - forward 10 mm. Now my tonearm's EL was precisely 270mm. By the way, I can easily adjust my tonearm very precisely - to within a fraction of a mm. As a warning to others who might attempt this, I should say that this adjustment must be done with some care so as not to bend the wand, which is somewhat narrower than a standard pencil and made of a soft alloy of aluminum. In my experience the most tricky thing in this adjustment procedure wasn't altering the length, but ensuring that through the adjustment process the golf ball and the tonearm mounting bracket remain perfectly parallel.

Here's the mystery. In 2009, in response to a query, Bill Firebaugh posted a memo stating that the correct overhang for a cartridge installed on the Amadeus was a half-inch. All of my cartridges installed on my Amadeus MkI (with the adjusted 270mm EL) have overhangs of (estimated by eye) very approximately a half-inch. So, based on your article's comments, it appears that the Amadeus MkII uses a different geometry than the MkI. Presently, because I am still unsatisfied, I am thinking more and more that I should obtain a Feikert protractor to do a Baerwald or Loefgren alignment. The slots in the tonearm mounting plate are somewhat oversized and have enough 'free play' to allow for a couple of degrees of offset adjustment. It should be noted that the cartridge mounting flange isn't fixed in place, it can be adjusted (via a philips head screw underneath) but the manual solemnly warns against this. But, precisely adjusting the Feickert might be problematic because, as Art noted, locating the tonearm's exact pivot point might be difficult or impossible. Parenthetically - I should remind people that course adjustments of overhang can be made risk-free by any owner because the fluid reservoir in the original Amadeus is about 1 cm wider than the golf ball, so the arm from which the golf ball is suspended can be swung fore and aft a few mm, and thereby altering the pivot-spindle distance, to compensate for discrepancies in the mounting hole to stylus distance among various cartridge makes and models.

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