Cartridge/Arm/Turntable Developments (Vol.2, No.1: 1979)

Presented below are the following carts: Fidelity Research FR-7; Koetsu; Pyramid RW-1 and RW-2; Supex SDX-1000 (preview); Technics SP-10 Mk II; Win Laboratories SDC-10 (preview); Win Laboratories SDT-10 Type IIC.

Part IV of our somewhat loosely connected series, this time focusing exclusively-more by coincidence than by design-on SOTA nominees and contenders. (Things won't look always this rosy.)

Before anything else, a quick apology. We regret that our promised turntable survey, with quantified comparisons of mechanically and acoustically induced sonic colorations in a variety of models, has been postponed until the next issue.

We don't feel terribly remiss about this; the measurements and evaluations involved are considerably more elaborate and time-consuming than in the case of, say, preamplifiers, and we simply aren't ready yet to publish a full re port. What happened was that, as we got deeper and deeper into the subject, new complexities and ambiguities kept cropping up. As usual. We also discovered considerable overlaps with, as well as divergences from, similar studies done by Poul Ladegaard for Bruel & Kjaer in Den mark and by Martin Colloms for the Hi-Fi Choice Series in England, all of which we want to sort out thoroughly before committing our conclusions to paper. This is relatively unexplored territory and, as we've said before, it's hard to schedule in advance the solution of un solved problems.

Don't expect, however, any radical contradictions of our previous opinions and recommendations when the final results are published.

As we go to press, it still appears from our continuing tests that mechanical resonances and acoustical breakthrough are of far greater importance in explaining audible differences in performance than boiler-plate specs like wow, flutter and rumble, which are almost invariably sub-threshold. Furthermore, sheer inertial mass and heroic measures of acoustical deadening, a la Cotter B-1, still appear to be unequaled by lighter-handed approaches when it comes to protecting the phono signal from all intrusions of extraneously generated energy. So don't look for any miracles from the latest lightweight, resonant tin can standing on four little rubber nipples.

Bad news from the VTA front.

We have only one piece of theoretical in formation to discuss here before the reviews, especially since the seminar transcript else where in this issue isn't exactly light on theory.

But this particular question is important and didn't come up in the seminar.

It seems that tuning the vertical tracking angle (VTA) by raising or lowering the back of the tone arm, or by shimming the cartridge, can under most circumstances yield only an advantageous trade-off rather than absolutely correct geometry across the board. (See also the letter to the Editor by F. Brock Fuller of the California Institute of Technology in our “ Box 392” column up front.) The reason is that the only correct orientation of the long and narrow contact area on a modern stylus is straight up and down. That's because the cutting edge of the cutter stylus is also oriented straight up and down on the wall of the groove as the latter is being cut, even though the vertical motion of the cutter stylus is at an angle to the perpendicular. If you then compensate for VTA error by tilting the pickup stylus tip and in effect angling the contact patches, you no longer have an optimized 'scanning aperture” and there will be a scanning loss in playback. A few degrees of VTA correction, while far from trivial when it comes to getting rid of audible FM distortion, will cause relatively small scanning loss. But the alignment can't be perfect, by definition, unless both the VTA and the contact patch orientation are 100% correct. And that will be the case only when playing records that were cut with the same vertical angle as the inherent VTA of the pickup. In other words-not very often. An industry-wide VTA standard is the only complete answer.

Now, going a bit further, if you have one of those typical present-day pickups with a VTA of, say, 29 degrees and then try to tilt it back by 14 degrees so it will play a 15-degree cut correctly, you're in deep trouble with almost any kind of elongated contact patch. There will be a significant scanning loss, as well as a definite torque on the tilted stylus tip as the groove tries to “straighten it out.” The latter effect can cause all sorts of whipping motion and ultrasonic activity, highly undesirable both from the standpoint of clean sound and of record wear. Of course, a 14-degree correction may be mechanically impossible to begin with, unless the bottom of the cartridge case slants upward in the rear. (See also Volume 1, Numbers 5 and 6.) It must also be added that a spherical stylus tip, with its round contact patches that have no orientation as such, is immune to these trade-offs. You can tilt a ball-point stylus back wards and forwards without changing the scanning aperture; you'll just have equally limited tracing ability and signal-to-noise ratio in all positions. A cartridge with a built-in VTA of 30 or 32 degrees might therefore be, paradoxically, better off having a stylus with round contact patches; at least you can apply massive VTA correction without side effects. Not that two wrongs add up to a right; the optimum pickup design for present records remains one with a VTA in the 15 to 20 degree range and a line-contact stylus tip. The advantages of such a stylus will be retained with a few degrees of tilt for VTA correction from record to record.

New literature on VTA.

The village atheist who professes not to believe in any of these superstitions about VTA is apparently still with us. One such professor, for example, recently stated in an audio club newsletter (not a learned journal, to be sure) that “VTA is for the most part nonsense” and that he is convinced that “those who hear great changes with VTA are using arms that are too flimsy and resonant.” (Like our FR-66s?) Luckily, for those who need further convincing or just want the most comprehensive information on the subject, there's some considerably more authoritative new writing on VTA just becoming available.

The monumental two-part paper by James V. White and Arthur J. Gust we've known about for some time is finally out; the March 1979 issue of the Journal of the Audio Engineering Society contains “Measurement of FM Distortion in Phonographs' and the April 1979 issue “Three FM Methods for Measuring Tracking Angles of Phono Pickups.” Almost concurrently, there's a more popular explanation of some of the same matters by Jim White in the June 1979 High Fidelity titled “Tracking Angle Error: A New Slant.” (Seventeen years old is apparently new to the hi-fi slicks.) These articles provide extensive references, bibliographies and/or credits, the latter including the never excludable Mitch Cotter. Dr. White's High Fidelity article begins with the sentence:

“The odds are better than 100 to 1 that, astonishing though this may seem, your phono graph's sound suffers unnecessarily from as much as 5% distortion due to vertical tracking angle error.” And that 5% refers to a flutter type of distortion, which even the dead can hear.

We trust that pip-squeaks who don't possess sufficient knowledge to be a file clerk to some of these distinguished researchers will now think twice before mouthing off about VTA from the third barstool on the left.

Fidelity Research FR-7

Fidelity Research of America, PO Box 5242, Ventura, CA 93003. FR-7 “pure” moving-coil phono cartridge, $660. Tested sample on loan from manufacturer.

This high-priced new flagship of the FR line is obviously an all-out bid for SOTA, and it falls short of the mark not because of sophisticated generator and stylus considerations but as a result of simple negligence of basic phono geometry. Once again, the VTA is ridiculously large; correction by lowering the back of the arm is prevented by the “professional” plug-in head configuration which leaves insufficient clearance for this maneuver. The integrated plug-in headshell also prevents any kind of twisting for lateral tracking error correction, which the pickup happens to need, alas, in the FR tone arms. So the battle is lost on account of trivia.

The really tough design problems, on the other hand, are beautifully handled in the FR-7.

The coreless silver coil and unique double mag net with four poles constitute a virtually ideal generator, with superior orthogonality and torsional damping characteristics, as well as very low impedance and high output. The naked diamond stylus with long and narrow contact patches also appears to be excellent, so in essence all is well except that the whole thing sits there cockeyed in the groove. What a shame.

The sonic outcome of all this is that the midrange, distinctly clearer than that of the FR-1 Mk 3F or any other moving-coil pickup known to us except the Koetsu, is still discernible and enjoyable through the messed-up geometry, but the highs just don't sound right-not quite clean enough. Surgical transplant into some more readily adjustable headshell arrangement would be the only solution, but it might make the total acquisition cost comparable to that of the Koetsu, so why bother? In our judgment, the incomparably less costly FR-1 Mk 3F is still this company's best shot at the title so far.

Koetsu

Koetsu, Inc., Japan. Imported and distributed in the U.S.A. by Sumiko Incorporated, PO Box 5046, Berkeley, CA 94705, and by Specs Corp., 1238 Green Street, San Francisco, CA 94109. Koetsu moving-coil phono cartridge, $995 or $1000 (depending on dealer). Tested sample on loan from Specs Corp.

Here we go again: this is our new reference cartridge. Sorry about that, but the Koetsu is simply the best we've ever heard. Its sound is clearer, more focused, more detailed, more solid, more “live” than that of any other cartridge known to us. We wish it weren't so, as we find the retail price nothing short of ob scene, but that doesn't change the quality or relative ranking of the product. (The price structure, in case you're interested, is $350 from manufacturer to importer, landed; $500 from importer to dealer; $1000 from dealer to consumer. Draw your own conclusions.) We're told that the Koetsu was designed by the retired chief engineer of Supex, a gentleman by the name of Sugano, who makes each sample by hand in collaboration with his son and sells only about one out of three, the other two being weeded out in a fanatically stringent process of quality control. (Don't hold us to this story; we didn't hear it from Mr. Sugano himself.) Only a few dozen pieces have reached these shores so far. The cartridge is easily distinguished by its rectangular capsule of wood, shaped out of a single block with beautiful grain and looking like the epitome of Japanese handicraft.

The stylus cantilever is no chopstick, though; it's a highly sophisticated structure of boronized aluminum (boron for high Young's modulus and propagation velocity, aluminum for low Q); in addition, its longitudinal axis intersects the diamond shank much closer to the actual playing tip than is usual, resulting in considerably superior dynamic behavior. The contact areas are of the tall and narrow variety, of course. The generator mechanism is equally advanced in design (samarium-cobalt magnet, special pole pieces, very high flux density-the works), and the power output in nano-watts is quite magnificent. So there are reasons for the good sound.

Interestingly enough, the Koetsu doesn't measure dead flat; there's a gently rising response above 10 kHz, up 6 dB at 20 kHz. We heard absolutely no zip or zing as a result, though, proving once again that amplitude response isn't the decisive spec.

And that's not all. The Mitchell A. Cotter Company has come out with a “dedicated” version of their moving-coil pickup transformer, wound especially for the impedance characteristics of the Koetsu cartridge and not adaptable to others by re-strapping. The model designation is MK-2L; the price, if and when you can get one, is $650. Ridiculous? Well, we hate to tell you this, but the cartridge sounds ever so slightly sweeter and more solid through this transformer than through the standard Cotter MK-2 with P strapping. The impedance match is right on the button instead of just in the correct range, and the last few dB of S/N ratio and dynamic range are therefore extracted from the Koetsu. It's the combination we have in our current Reference A system.

Of course, if you don't make your living with audio and your dollars or yen don't come from the petroleum business, all this may seem like outrageous overkill. We wouldn't be doing our job, though, if we didn't report that nothing else we know of is quite as good. Over priced, yes; swindle, no.

Pyramid RW-1 and RW-2

Pyramid Loudspeaker Corporation, 131-15 Fowler Avenue, Flushing, NY 11355. Model RW-1 turntable weight, 875; Model RW-2, $60. Tested RW-1 sample on loan from manufacturer.

The RW-1is a 1 kg (2.2 lb) weight, milled out of a single block of stainless steel in an aesthetically pleasing shape, beautifully polished, with a spindle hole in the center of its bottom side. It fits snugly on the spindle of your turn table and virtually welds the record to the turn table mat, so that the grooves move strictly in accordance with the dictates of the platter, without any mechanical freedom of their own (well, almost without any). In other words, the disc is mechanically grounded to a much larger mass. The resulting absence of the tiny gives and takes and shifts and vibrations that are in evitable with a less positively located disc does indeed make an audible difference; the sound is distinctly cleaner and better focused, at least in a system of reference quality.

The RW-1 is too heavy for any but the really high-torque turntables, such as the Technics SP-10 Mk II and other top-of-the-line direct drive models; for most users the lighter RW-2, which is only 500 grams (1.1 lb), will be the recommended weight. Of course, the greater the hold-down force, the better, especially for flattening certain stubborn warps.

Two reservations must be added. One is that no turntable weight of this type can correct a concave warp, since the center of the disc is already depressed and the weight can't hold down the outer edge. The other is that almost any kind of homemade weight could probably do the same overall job at much lower cost, but the Pyramid RW-1 happens to be an object of irresistible visual and tactile appeal.

Supex SDX-1000 (preview)

Sumiko Incorporated, PO Box 5046, Berkeley, CA 94705. Supex SDX-1000 moving-coil phono cartridge, $500. Auditioned one sample on private loan.

Just before press time, we had a very brief opportunity to listen to this latest top-of-the line Supex in our Reference A system. The lateral and vertical alignments were carefully performed, so we're convinced that what we heard was valid.

We can report that this is an excellent moving-coil cartridge but not quite as good as the Koetsu, to which the SDX-1000 is intended to be the half-priced answer, we're told. The Koetsu is comfortably superior in smoothness, transparency, resolution and signal-to-noise ratio, the latter because of its vastly greater output capability. The Supex might even get beaten in a runoff against the FR-1 Mk 3F, a comparison we unfortunately didn't have time for. We believe the FR is possibly a wee bit smoother.

That's all we can tell you until next time; we suspect even this short preview will be more than what you'll see elsewhere about this very new and far from negligible product.

Technics SP-10 Mk II

Technics by Panasonic, Panasonic Company, Division of Matsushita Electric Corporation of America, I Panasonic Way, Seacaucus, NJ 07094. SP-10 Mk II three speed direct-drive turntable with SH-10E power unit, $800 (chassis only, without base). Two-year warranty; carry-in service. Tested #DA7728B016, on loan from manufacturer.

In the last issue we promised a final vote of preference between this turntable and the Denon DP-6000, as mounted on the Cotter B-1 base in each case. (Remember, in the price-no object category we can't wholeheartedly recommend the base of any Japanese direct-drive turntable known to us.) The nod goes to the SP-10 Mk II, not because of sonic differences but because it's a thoroughly professional piece of gear, capable of tremendous torque, built like an anvil, and virtually immune to abuse.

For example, the technically most sophisticated FM station in our area, WNCN, has them running all day and all year without any problems. By comparison, the DP-6000 appears somewhat fragile and fussy, although its tachometer system (magnetically recorded reference track read by a magnetic head) is perhaps more refined and accurate, even if susceptible to misalignment. The issue has become more or less academic, since the DP-6000 is now off the market. Its successor, the DP-7000, is certainly not less fragile or fussy; the much costlier new DP-80, on the other hand, has a huge motor and looks like Denon's idea of a real blockbuster to pit against the SP-10 Mk II, but we haven't had our hands on one so far.

Another advantage of the SP-10 Mk II is its third speed; even if you never play any 78's it's great for speeding up test records and for really brisk cleaning with a record brush. We also like the brute-force electromechanical brake; it stops that powerful motor with astonishing abruptness, unlike those sissy electronic brake systems. Unfortunately there's no speed adjustment; the quartz-crystal phase locked control is engaged at all times. Tough if you have absolute pitch.

Our initial experiments with measurement techniques for the quantitative comparison of mechanical resonances and acoustical break through seem to indicate that the SP-10 Mk II in the Cotter B-1 system is something like two orders of magnitude better than typical audiophile turntables on their factory bases.

It's a difference you can easily hear, although the Denon-Cotter combination is just as good sonically. More about all that in the next issue, as promised.

It's possible on occasion to confuse the servo loop of the SP-10 Mk II with a new push button command and initiate cogging. This is most likely to happen when shifting to a lower speed without going through stop. You'll notice it immediately because when that big motor cogs, it makes the whole turntable shake. The thing to do is to stop the platter and start again at the desired speed. That's all; once the servo locks to the correct speed, cogging will definitely not occur spontaneously. It's about as much of a nuisance as starting your car now and then with two attempts instead of one; we can live with it. It's also possible that some sort of fine-adjustment of the power unit would cure this tendency permanently. We haven't bothered.

Until further notice, then, the Technics SP-10 Mk II in the Cotter B-1 base is our reference turntable.

Win Laboratories SDC-10 (preview) Win Laboratories, Inc., PO Box 332, Goleta, CA 93017.

SDC-10 DC Servo Reference Turntable, $2000. Tested #3, on loan from manufacturer.

This absolutely magnificent-looking turn table, a veritable sculpture in polished metal and clear plastic, arrived too late to be evaluated in depth against the Cotter B-1 system with the SP-10 Mk II, which is the only standard we could possibly judge a new $2000 unit by. (The price of the Win may even go up to $2350, we're told, if a slightly different motor with higher torque is decided on for later production.) So you'll just have to wait for our long delayed turntable survey in the next issue if you want nitty-gritty comparisons between the two.

Meanwhile, a few general observations:

The SDC-10 is a belt-drive turntable; you could say it's the ultimate embodiment of the Linn/Thorens approach, with rigidly clamped motor and synchronously jiggling platter and arm on soft springs. The DC servo motor is controlled by a circuit housed in a separate cylindrical switchbox; the two speeds are vernier adjustable. Although the platter itself is quite heavy (9'2 1b), it's our initial impression that the overall mass of the SDC-10 is still too small to present a really high mechanical impedance to brutal extraneous excitation. (We made the same comment about the Linn-Sondek a couple of issues back.) You can't manhandle the top plate of the Win with quite the same abandon and impunity as that of the Cotter. But then it's almost instinctive to treat such a beauty with a lighter hand.

This is not to suggest that the isolation and acoustical deadening of the SDC-10 are anything less than outstandingly fine. We originally suspected that the monolithic leaded plastic material of the translucent base would be no match in deadness for the laminated structure used in the Cotter B-1, but our first tentative measurements of mechanical resonances and acoustical breakthrough indicate no such inferiority. We find that quite remarkable. A few little anomalies we detected in the Win still need some sorting out; they may well turn out to be artifacts of our initial test setup.

Our listening evaluations so far have involved some discrepancies of the apples vs.

oranges variety, attributable to the use of different arms and cartridges. We'll reserve judgment until a more uniform procedure is established. In any event, we figured that a preliminary report about a new superstar is always better than no report at all-which is what would have been normal with this kind of lead time.

Win Laboratories SDT-10 Type IIC (follow-up)

Win Laboratories, Inc., PO Box 332, Goleta, CA 93017.

SDT-10 Type IIC semiconductor disc transducer, complete with power source module, 3350 ($550 after June 1, 1979). SPG-10 passive volume control module, with wide faceplate for both units, 3150. Tested samples on loan from manufacturer.

If you think this is our final, definitive re view of the Win strain-gauge cartridge, we may have to disappoint you. Not that we haven't had enough time to find out all about it or that we have the slightest hesitation about our conclusions. It's just that the SDT-10 represents a new technology in a state of ceaseless evolution, difficult to pin down at any given moment.

We're unaware of any recent three or four month period during which the SDT-10 remain ed totally unaltered physically and sonically.

Not because Dr. Win can't make up his mind but because he is a scientist and a seeker of truth who can't stand being aware of a possible improvement and then not incorporating it immediately in his product for hard-nosed commercial reasons. (He ought to take a few lessons in the expedient spacing of upgrades from Joe Grado.) So we must first of all make sure which SDT-10 we're talking about.

Type IIC is the very latest version as we go to press, possibly so new that your dealer may still have a few of the older Type II in stock.

The C suffix stands for Cycoenea, a proprietary name for a new alumina-based material of which the beam structure holding the semi conductor strain-gauge element is made. The older Type II had a pure alumina beam. A further difference is that Type I1IC has a stylus cantilever made of boron on a graphite core, whereas the immediately preceding Type II has a slightly different boron cantilever with a tungsten carbide core. And that's not all. Dr.

Win buys line-contact diamond styli both from Weinz in Germany (Paroc tip) and from Ogura in Japan (Vital tip), and he supplied us with his magnificently crafted plug-in stylus assemblies utilizing each type. And that's still not all. He also sent us various experimental styli utilizing other cantilever materials besides boron. So, even if we aren't exactly confused, we've had a surfeit of input to say the least.

Let's try to keep the whole thing as simple as possible. We can recommend the dead-stock, garden-variety Type IIC without serious reservations; it's one of the best cartridges around.

But it happens to be the second best Win cartridge we've auditioned so far; the first best was the older Type II with a titanium stylus cantilever and Vital tip, a configuration not avail able commercially because Dr. Win feels that titanium develops metal fatigue much too easily. And again, that's not all. We had to raise the back of the arm way, way up to compensate for the rather small VTA of this cartridge and-get this-we had to apply 4 grams of tracking force to help damp out ultrasonic activity in the stylus and make the output sound as good as possible. Set up this way, and with the Win SPG-10 passive volume control replacing the entire preamp, this particular nonstandard combination of cartridge and stylus sounded absolutely stunning. The highs were the cleanest and fastest imaginable, and the rest of the range was almost as good. Only a very slight woolliness and smearing in the upper bass and lower midrange made us rank this sound below that of the Koetsu through the Cotter front-end modules. No other competition is visible. The stock Type IIC is very close in overall performance but not quite as smooth and transparent. It, too, benefits from increased stylus force beyond the officially recommend ed 2 grams and needs lots of VTA correction in the plus direction.

Now, what does all this add up to? We have spoken to Dr. Win about our findings and he is in basic agreement with us on most of the essential points. He believes that further damping of acoustical activity in the cantilever is indeed desirable and feasible, but he insists that it can be achieved with boron and with a vertical tracking force of 2 grams. He also agrees that his current VTA (14.5 degrees in Type II1C at 2 grams) may be on the low side for modern records and should be increased slightly. He is even working on a totally new technique to eliminate all needle drag (longitudinal translation) effects, which in our opinion may be the reason for the slight remaining imperfections.

So, as you can see, the Win cartridge is a continuing process rather than a frozen product.

We feel that under the circumstances the consumer simply can't demand greater finality.

A strain-gauge transducer with this kind of gauge factor, resulting in this kind of S/N ratio and dynamic range, would have been considered a wild dream only a few years ago. The surprising thing is that it exists at all, not that it isn't 100% finished. And even unfinished it's better than almost everything else around.

What's our immediate recommendation? If you don't care about the cost, go the Koetsu/ Cotter route. If you don't think you need the switching and control functions of a preamp, you could save a lot of money by choosing the Win SDT-10 with its almost 1-volt reference level output. No preamp, with the possible exception of the Cotter, is as transparent as it ought to be, so you'll be way ahead on that count alone. And the latest SDT-10 approaches the performance of the top moving coils, pre amp or no. The SPG-10 will take care of the volume control function without any problems.

Of course, the longer you wait, the better the SDT-10 will get; past experience points inevitably to that conclusion. But even if you get one tomorrow, we don't think you'll regret it. It's a technological tour de force. (We don't like that last-minute $200 increase in price, though.) Recommendations As always, we implore you to read every word in the reviews instead of simplistically depending on these summarized ratings. You won't be able to make an intelligent choice if you go by the “box score” alone. A number of recommendations have changed since the last issue; some of them remain the same.

Best phono cartridge tested so far, regard less of price: Koetsu.

Close to the best at an incomparably lower price, though still expensive: Fidelity Research FR-1 Mk 3F.

Special situation for the experimenter who.

can do without a preamp: Win Laboratories SDT-10 Type IIC.

Best tone arm tested so far, regardless of price: Fidelity Research FR-66s (if you have the room for it) or Fidelity Research FR-64s with B-60 stabilizer.

Best separate tone arm per dollar: Series 20 Model PA-1000.

Best turntable tested so far, regardless of price: Cotter B-1 system with specially adapted Technics SP-10 Mk II.

Best turntable per dollar: See Reference B discussion in this issue (this is rapidly shifting ground).

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[adapted from TAC]

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Also see:

Diamond Styli for True High-Fidelity Reproduction -- By Dr. Sao Zaw Win, Win Laboratories, Inc.

Three New Step-Up Devices for Moving-Coil Cartridges: Audio Standards MX-10A; Fidelity Research FRT-5; Marcof PPA-1

Symmetry ACS-1 -- John Curl's Perfectly Coherent Electronic Crossover

Various audio and high-fidelity magazines