Follow-Up, October 2011
Art Dudley returned to the Thomas Schick tonearm in October 2011 (Vol.34 No.10):
Having purchased my review sample of Thomas Schick's transcription-length tonearm ($1475), I decided to have some fun and try it on a turntable other than my beloved Thorens TD 124namely, my more recently acquired Garrard 301 motor unit. In the process, I took a fresh look at all the installation and alignment data I've accumulated for the Schick, in light of both Keith Howard's watershed article for Stereophile on tracking geometry ("Arc Angles," also in the March 2010 issue) and my own cartridge- and tonearm-measurement jigs, fashioned over the past several months. The observations that follow are aimed at those readers who are acquainted with Howard's article; are convinced they might achieve lower levels of tracking-error distortion by thus looking beyond Baerwald for phono-alignment specs; and are willing, if not happy, to invest the extra time and care in so doing. This is in no way a refutation of the very sound engineering work behind the Thomas Schick tonearmwhich, if installed according to its manufacturer's guidelines, will exhibit good Baerwald geometry, and will sound superb.
Schick tonearms are available for use with either G- or A-style pickup heads, the respective stylus-to-collet dimensions of which are 52 and 30mm. (Ortofon's current technical drawings show the G-style dimension as 51mm; having measured about 10 different samples during the past year, and while noting a window of variability of approximately 0.75mm, I can declare with confidence that the reality is nearer to 52 than 51.) My Schick, which has an offset angle of 17.11° and an effective (stylus-to-pivot) length of 317.57mm, is made for G-style heads; a Schick arm made for A-styles has precisely the same offset angleand, interestingly, the same effective length: Its only difference is an additional 22mm of armtube ahead of the offset bend, to compensate for the shorter A-style head. Thus the owner of one Schick arm could conceivably buy and use the other without moving the arm-mount collet at allsurely the neatest way of doing things.
My intent this spring was to use my G-style Schick with an A-style pickup head, which isn't nearly as dumb as it sounds: Although my measurements confirmed that the Schick is designed and built to exhibit perfect Van Baerwald alignment with an appropriately sized pickup head, it doesn't conform to Keith Howard's recalculated (in light of newly measured LP-groove layouts) alignment data, and the Schick's fixed offset prevents the making of after-the-fact adjustments. That doesn't mean we can't do it: It just means it takes a bit of work (footnote 1).
First, before drilling any holes, I decided to confirm the Schick's effective length. Given the arm's intended effective length of 317.57mm, it seemed reasonable to assume that, with an A-style pickup in place, that dimension would be reduced by exactly 22mm, for a result of 295.57mm. Now: Of the three or four measurement jigs I made last year, one is a long, boxy platform with very precisely drilled arm-mount holes at either end (one sized for the Schick, the other for my EMT 997) and metric rules penciled onto its surface, the zero points of which coincide with the precise centers of the aforementioned holes. You can pretty much guess the rest: The idea is to snug the tonearm into the hole, install the pickup, adjust the downforce, carefully lower the stylus, and see where it lands. Mounted in my Schick arm and adjusted for 2.8gm of downforce, the stylus of an A-style Shindo SPU pickup landed halfway between the marks for 295 and 296mm. Your Honor, I rest my case.
Thus emboldened, I returned to my wife's Dell computer and used Keith Howard's ArmGeometer software (footnote 2) to map out the new mounting dimensions, beginning with the program's first function, "Calculate optimal overhang and offset for specified arm dimensions." I plugged in the new effective length, along with an inner recorded radius of 56mm and an outer recorded radius of 146.3mm. (These dimensions differ from those stated by the International Engineering Consortium yet are demonstrably correctand are among the modern revelations that spurred KH's research on the topic.) ArmGeometer then told me, unflinchingly, that such an arm should exhibit an overhang of 12.59mm and 17.72°.
Note that the latter is close to the Schick's own 17.11° offset, the Schick being only 0.61° short. Note also that, as KH discovered, an offset error of x° can be virtually neutralized, in terms of lateral tracking-error distortion, by an equal error of xmm in overhang, as long as both errors point in the same direction (ie, too great or too small). Thus, because the Schick's written-in-stone offset angle is 0.61° too small, we must make its overhang too small by that number of millimeters. By subtracting 0.61 from 12.59mm, we arrive at the perfect overhang for a Schick arm with an A-style pickup head: 11.98mm. Subtracting that number from the new effective length of 295.57, I arrived at the optimum spindle-to-pivot mounting distance of 283.59mm. Now it was time to drill.
Going back to ArmGeometer and using its third function, "Generate graph data for LTE and LTE distortion vs. groove radius," I was able to plug in the newly determined overhang as well as all the other pertinent dimensions and learn, by examining the resultant data, that the two zero-distortion "null" points for this arm in this installation are 61.9 and 111.9mm (footnote 3). Those figures serve more as a confirmation than a goal; if the tonearm mounting hole is accurately drilled with respect to the above data, a millimeter or two of playeasily achieved by loosening and retightening the bolts that hold the motor unit to the plinthare all that's needed to achieve utter perfection.
If anything, the Schick tonearm, reinstalled as described above, sounded even better on my Garrard 301 than on my Thorens TD 124, with enduringly excellent musicality, freedom from strain on peaks, and lack of perturbability by record defects. After more than a year's use in my home, and with several more pickup changes than average under its belt, the Schick's bearings remain serenely free of friction, and its locking collet remains the smoothest and surest of any I've tried. (It's also worth noting that the arm's wooden armrest, which I originally described as "slightly rough" in appearance, has been improved in subsequent production runs, and is now quite pleasant to use and behold.) Wince if you must at the notion of declaring a four-figure phono product a "bargain": The Schick tonearm is an outstanding value, and easily the most accessibleand hassle-free, especially for users who are content not to stray from the manufacturer's installation and alignment recommendationstranscription-length arm on the market.Art Dudley
Footnote 1: One might even see the nonadjustability of the offset angle of the typical transcription tonearm-pickup combination as an advantage, if only because, during cartridge alignment, offset angle is infinitely more difficult than overhang for the consumer to dial in. Assuming that the designer has accurately stated the tonearm's offset angle, that leaves the comparatively easily adjusted overhang dimension in the hands of the buyer: a much safer bet. Just sayin.'
Footnote 2: This Windows-based program can be downloaded without cost from Keith Howard's website.
Footnote 3: Without actually plotting the graph, one can determine those dimensions simply by noting the radii at which the data cross the zero line from positive to negative and back again.