SME 3009 tonearm
There are two models available, differing only in pivot-to-stylus distance and in total mass. The Model 3012 is 12” from pivot to stylus, to accommodate old broadcast-type 16” transcriptions, but its mass is too high for the majority of to day's high-compliance pickups. The 3009 (with 9” pivot-to-stylus distance) is the arm we recommend for the home user, and it shares with the 3012 the distinction of being the most versatile conventional-type tonearm on the market today. It has wide-range adjustments for tangency, height, static balance, torsional balance, pickup tilt, bias compensation, and tracking force. The latter is adjustable over a wide enough range to accommodate a Euphonics Miniconic or an Ortofon pickup.
Other features include a damped hydraulic lifter that lowers the arm gently onto the record when released (and then disengages itself), a wooden lining inside the arm tube, to reduce torsional and longitudinal resonances, and a flexible decoupling system for the counterweights, to provide "dynamic damping."
For mounting, the SME requires an elongated hole 1” wide by 2¾” long, ranged by four small holes for the mounting screws. The screws hold a metal bed plate with an elongated cutout in it, and the arm base passes through this plate. Tangency is adjusted by loosening a pair of knurled nuts beside the arm base, and sliding this along the bedplate. Templates and detailed instructions are supplied with the arm, and a precut mounting board (Model A39M) for the Thorens TD-121 or Thorens TD-124 turntable is available from Shure Bros, for $15.
One of the templates suppliedthe tangency locatorhas a pinhole point that is supposed to accommodate the pick up's stylus tip. We do not recommend punching the pinhole; one slip of the hand, and the trapped stylus of a modern high-compliance pickup could be ruined.
We suggest simply placing the stylus directly on the pinhole location on the template. This way, the stylus will be free to slide across the template if the arm or turntable shifts slightly during the tangency adjustment.
Interconnections between the fine tonearm cables and the heavy shielded output cables are made at a plug-in contact strip under the base of the arm. An oval metal tube slides over the plug assembly to shield the entire junction. The output cables are 48” long and terminated by labeled and color-coded phono plugs. Output wiring is five-circuit, providing isolated ground returns for both channels, plus a separate grounding circuit for the tonearm and turntable, for connection to the preamp chassis via a spade lug.
Stylus force is selected by a counterweight that slides along a calibrated rod. With the slide weight set at zero, the arm is adjusted for zero tracking force via a large ring weight at the rear of the arm. With the static balance set, each calibration on the slider weight's scale represents a half-gram increment in tracking force. We found this to be the most accurate calibrated force adjustment on any arm we have tested.
Torsional balance, which distributes the arm's weight equally between its two knife-edged vertical pivots, is accomplished by sliding a lateral rod (which holds the calibrated-scale weights) at the rear of the arm. This varies the distance between the weights and the arm tube's axis, imposing different amounts of twisting leverage to offset the normal twisting due to the arm's offset head. All preset adjustments except tangency are fixed via setscrews, by means of an Allen wrench supplied with the arm.
The "anti-skate" bias compensation is adjustable by hooking a small nylon cord around the appropriate notch on a small rod at the rear of the arm. Each notch corresponds to a calibration mark on the tracking force scale, to provide the proper amount of compensation for a given stylus force.
Considering its versatility and its strikingly handsome, businesslike appearance, it would be a shame to have to report that the SME was a lousy tonearm. Fortunately, we don't have to. As a matter of fact, we found that we could get cleaner tracking at lower forces from this arm than we have from any other commercial arm tested to date. It was a delight to use and, since we test a good many different pickups, we found the SME's adjustment facilities so ideally suited to our purposes that we have adopted it as our new standard tonearm for pickup tests. To date, the only fault we have been able to find with it is in its dynamic damping system, which does not seem to work the way theory says it should.
Isolating the counterweights from the rest of the arm via a flexible coupling is one recognized way of reducing the amplitude of the low-frequency resonance that normally develops between the pickup's compliance and the combined mass of the pickup and arm. The idea is that, at the resonant point (where the whole arm normally wiggles from side to side), the de coupling allows the arm to vibrate without carrying the full mass of the counter weights with it. The effect of this is to reduce the total mass at around the resonant frequency, broadening the resonance and reducing its amplitude. This is a fine idea, in principle, but we have yet to find a tonearm in which the "dynamic damping" principle worked according to theory. In our sample SME, the decoupling appeared to be almost totally ineffectual, and the arm behaved pretty much as though it were undamped, which is to say it proved to be just about as susceptible to acoustic feedback and physical jarring as any other undamped tonearm. As a consequence, the turntable must be well isolated from floor-borne vibrations, either by means of a highly flexible suspension system or by location on a particularly rigid part of the room's floor.
The SME is unquestionably the finest universal tonearm for the hobbyist that we've found to date, but it could be improved a bit, too. With properly designed viscous-damped pivots or a dynamic damping system that worked, this arm would probably be unbeatable.