Behind The Scenes (June 1979)

by Bert Whyte

Recently I was rummaging through some old papers looking for an article, and I ran across a 1951 hi-fi catalog. I got quite a kick browsing through it and recalling many of the components, which in their day were considered quite advanced. Magnetic phonograph cartridges were relative new comers to the market and were a significant improvement over the crystal and ceramic piezoelectric types. Listed as the General Electric variable-reluctance magnetic cartridge, selling for $5.95! Obviously, back in those good old days, inflation was something you did to automobile tires.

Shortly thereafter I had the pleasure of visiting Joe Grado at his home. As am sure many of you are aware, Joe Grado is one of the pioneers in manufacture of magnetic phono cartridges, and his products have occupied their special niche in the hi-fi components market for over 25 years. I was talking to Joe about that old catalog and the $5.95 GE cartridge, and he pointed out that now, 28 years later, his F-1 magnetic cartridge sells for just $9. It is, of course, a far more sophisticated design, light years ahead in performance than the old GE unit, and just another example of why hi-fi components are still considered the best value among current products.

Joe Grado is no stranger to the pages of Audio. His interesting and provocative articles on turntables, suspensions, and shock mounting have elicited much favorable comment. Joe is quite an iconoclast, and many of his ideas and techniques are considered both unorthodox and controversial.

While Grado Laboratories has grown and prospered over the years, Joe is the first to admit that it is a small operation compared to the giants in the field. And that is the way Joe wants it. As his own man, free of any managerial constraint, he is able to pursue any line of experimentation that he finds of interest. Joe is an inveterate and indefatigable experimenter in his own field and in allied audio interests. In fact, this activity has caused some tongue-in-cheek comments about him, such as ... "If you bought this Model X cartridge on Monday, come back on Friday, and you can buy the revised, updated Model X, Mark Two." Among other attainments, Joe is an operatic bari-tenor who is good enough to have sung lead roles with some opera companies here and abroad. He has tremendous output, and when he belts out an aria from "Otello," believe me, your ears will ring! His singing and his abiding love of music have helped to develop his keenly analytical ear for sound quality.

All the Grado phonograph cartridges, with one exception, are manufactured at the Grado Laboratories' factory in Brooklyn, N.Y. The exception is the "Joseph Grado Signature Three "model, which is hand made in a small laboratory in Joe's home. I spent most of a day in Joe's home lab where he showed me the fascinating process of how he personally makes and tests his Signature Three phono cartridge. During that time, Joe discussed some of his theories with me and explained the rationale of some of the design features of his cartridge. At this point, I should note that Joe Grado is in the unique position of manufacturing the least expensive magnetic cartridge in the field, the F-1 at $9, and the most expensive, the Signature, Three, at a rather breath taking $750!

High-Priced Parts

It must be admitted that high-end audio components have been getting very high indeed of late. With Infinity, Beveridge, and Plasmatronic speakers priced between $6000 to $7000 a pair, the new Infinity amplifier at $4000, the GAS Godzilla at $3500, and a pair of mono Mark Levinson ML-2 amplifiers at $4200, those are pretty rarified prices! In relative terms, the $750 Signature Three cartridge would appear to fall right in with this group. Unquestionably, many of the owners of this exotic equipment do use the Signature Three.

However, because a phono cartridge is such a small component and because no other cartridge has ever been priced this high, many audiophiles are outraged at what they consider a "rip off!" The Signature Three has become the "darling" and "in" cartridge of the underground "audiophile" publications, and while they are lavish in their accolades for this cartridge, they also moan and groan about the price.

The Signature Three is a magnetic cartridge of the moving-iron type. You would think that in a cartridge in this price range, the cantilever would be made of some exotic material like beryllium or titanium. Joe stated he had researched these and other materials, and they exhibited resonances which he found unacceptable. If anything can be said to characterize Joe's designs, it is his almost fanatic quest for the reduction of spurious resonances. Joe feels that resonances are often the hidden culprits in the creation of sound coloration, which diminishes the clearness or flaws the illusion of reality of the sound. In light of this, Joe uses a hardened, tapered aluminum cantilever, which is internally coated with a special damping com pound to reduce resonances. The coils in the cartridge's magnetic circuit are wound on precision machined bob bins, using a very fine wire, and, because of the design, use a minimum number of turns of wire. This results in a cartridge of very low inductance and raises the resonant peak far above the audio range.

There are four separate and independent magnetic gaps, and I watched Joe, working with a high-powered magnifier, precisely position the cantilever in the center of the four gaps and cement it in place with a tiny spot of epoxy he had melted in a small lab oratory furnace. At the base of the cantilever there is a tiny ring of a very special "pure" iron, which exhibits very low hysteresis effects and has the property of being magnetized very rapidly and, conversely, of equally rap id demagnetization. The motion imparted to the cantilever by the undulations of the recorded signal moves the tiny iron ring in the center of the four gaps, increasing and decreasing the intensity of the magnetic flux in the four independent gaps.

The result is a balanced magnetic circuit of high efficiency, and, unlike most cartridges, it does not require heavy mu-metal shielding. The stylus Joe uses is what he calls the "twin-tip," which is, in essence, a twin spherical tip. If you imagine a screwdriver blade in the record groove, with the shoulders of the tip ground off to spherical shape, you'll get the idea. Joe states that this affords less mass and better tracking than the typical "long line contact" types. He also says that this design does not exhibit vertical angle changes, and as a consequence "stick-slip" is greatly reduced.

Stylus-Groove Friction

Stick-slip is a function of the friction between the diamond of the stylus and the vinyl ,of the record. Although one thinks of the stylus "gliding" along a record groove, as the vinyl passes underneath the stylus, friction tends to "pull" and slightly deform the vinyl up to the point where there is finally a "catastrophic" release of the vinyl . . . and then the process begins all over again. All this causes what might be termed a subtle or, in bad cases, an extreme groove "chatter," with subsequent physical damage to the record groove.

Engineers are aware of this phenomenon, and, at present, there is work going on to produce a satisfactory groove lubricant, which will neither leave a residue nor degrade the record either physically or sonically. As a matter of fact, I recently heard a record treated with an experimental lubricant, and there was no question that the reduction of stick-slip definitely gave cleaner, better-defined, high-frequency response.

Grado also put a piece of a temperature-stable elastomer in the cantilever structure, not for damping, as is the usual case, but to maintain the pivot center of the assembly. Joe claims that his Signature Three cartridge has the lowest effective tip mass of any existing cartridge and says optimum performance of his cartridge is via a damped, medium-mass arm. He is, in fact, working on a radically new type of arm, which he claims will literally "couple" the arm/cartridge to the record groove. It may be introduced this fall.

There are also a number of very critical adjustments Joe performs on his cartridge, in conjunction with exhaustive tests on his lab bench. The cartridge is fitted into the special Technics EPA-100 tonearm which is only sold as part of the SL-1000 turntable with its beautiful 37-pound lava rock and epoxy black base. For testing, Joe uses a General Radio frequency response tracer, a Hewlett Packard spectrum analyzer with various test records to check harmonic distortion and intermodulation distortion, special pulse tests for transient accuracy, and others.

To show the consistency and accuracy of his Signature Three cartridges, Joe ran through about 15 different cartridges playing back some high-quality music recordings, and for all practical purposes, the sound was the same for all units.

Cost Consciousness

Now for the all important question ... can one justify $750 for a phono cartridge? Is it worth the money? First off, there are many fine cartridges on the market, far lower in price, and for many people they do a good job. It must be said that many of these people either do not have systems of requisite high quality or are aurally incapable of discerning sonic differences between the cartridges. Still others have listening situations with so many variables in speaker response, preamps, room acoustics, etc. that they might be misled in any comparison tests. For example, a moving-coil cartridge with a "peaky" or sizzly top end might sound good by virtue of a speaker that has a compensating rolloff in its high frequency response.

No, the Signature Three is not a cartridge for everyone. It has qualities that demand it be played on the very best equipment. There are those audiophiles who favor the sound of moving-coil cartridges over moving-iron or moving-magnet types, and vice versa. In the purest sense this shouldn't be a factor, as ideally, the best cartridge will not have a "distinctive" sound at all. If it does, coloration of some sort is lurking somewhere. It must be acknowledged that many people like these "colorations," either because they correct sonic faults not readily evident elsewhere in the listener's system or they just find them to produce a sound they think is accurate and realistic.

I have listened to many fine cartridges of all types, but in overall smoothness of sound, for outstanding resolution of inner detail, for transparency and the perception of depth, for clean, solid, well-defined bass, and, above all, for lightning-fast transient response, the Grado Signature Three is in a class by itself. I hasten to add that the very highest quality recordings are necessary to find out what this cartridge can do. The quality of information that can be extracted from the best of the direct-disc and digital recordings is truly impressive and gratifying. It would be nasty to say that you "gets what you pays for" and there are plenty of other cartridges that you can live with, but if your Aunt Fanny leaves you a small remembrance, you should listen to this exceptional phono cartridge.

(Source: Audio magazine, June 1979; Bert Whyte)

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