Listening #73 Page 2

Now, because a cutter head works on the same principle as a phono cartridge (only in reverse), then as long as its input voltage remains constant, velocity will remain constant as well—and groove amplitude will decrease as frequency rises. Thus, left to its own devices during the mastering stage, an electromagnetic cutter head cuts a constant-velocity groove, creating groove modulations that vary in amplitude with changing frequency.

Particularly within the three or four octaves that comprise the midrange, that's a piece of cake, and the systemic changes in amplitude introduced to the master disc by the electromagnetic cutter head are automatically compensated for by the equal but opposite systemic changes in amplitude introduced during playback by the electromagnetic phono cartridge. No problemo.

But the overall voltage range of the system still needed to be roped in—in addition to which, something had to be done to keep the sheer physical size of the groove itself consistently manageable. In 1925, it became clear that reproducible frequencies both above and below those three or four midrange octaves had to be dealt with differently, so the engineers decided to cut their record masters at a constant amplitude for bass and treble frequencies alike, producing modulations that vary in velocity with changing frequency. They did that by using simple, single-pole filters to attenuate frequencies sent to the cutter head below their constant velocity range, and to boost frequencies sent to the cutter head above that range (footnote 1). (By systemically changing the voltage, velocity was also changed—and amplitude became the constant.) That, of course, was done with the expectation and understanding that the phonograph amplifier would apply complementary filters during playback.

By 1954, the technology described above had evolved into what we now know as the Recording Industry Association of America's RIAA characteristic: 500.5Hz defined the lower limit of the constant-velocity range, and 2122Hz was the upper limit (footnote 2). Below 500.5Hz, the signal to the cutter head was rolled off at a rate of 6dB/octave. Above 2122Hz, the signal to the cutter head was increased at the same rate. And, of course, playback gear was (and is) designed to compensate for that, with a complementary bass boost and treble rolloff.

Between 1925 and 1954, however, there was never a set of defining frequencies that was universally agreed on throughout the industry: Virtually every record label in North America and Europe used a different pair of frequencies as the "hinges" of their filters. (Despite the occasional appearance of some mildly confusing preamplifier labels, it is the frequencies and the frequencies only that differ; the slopes themselves are always single-pole, 6dB/octave types.) The record label Musicraft, for example, began their treble rolloff at 2122Hz, but their bass turnover began at a relatively high 800Hz, whereas Brunswick began their treble rolloff at 2500Hz and their bass turnover at 629Hz. And so it went.

Re-equalization
I know those numbers not because I'm smart, but because I have in front of me the owner's manual for the Rek-O-Kut Re-Equalizer ($349), perhaps the least expensive and easiest to use of all 78rpm-specific equalizers on the market (footnote 3).

A reason for that: Whereas most such products are designed as standalone phono preamplifiers with full gain and equalization facilities, the Rek-O-Kut Re-Equalizer is designed to work with the gain and EQ already provided by an existing phono preamp, whether built in to a full-featured preamp or itself a separate unit. (The Re-Equalizer, in fact, is a unity-gain device.)

The Rek-O-Kut, which has a pair each of Input and Output jacks on its rear panel, is intended for connection to any buffered tape loop or effects loop within the user's preamp or integrated amplifier. (Absent a loop, one can simply place the Re-Equalizer between preamp and power amp—which is what I had to do.) Once energized by the supplied 24V wall wart, the Re-Equalizer remains powered up at all times, the only user controls being a front-mounted Bypass toggle for switching the unit in and out of the loop, and the two eight-position rotary switches for selecting bass Turnover frequency and treble Rolloff. Both of those knobs include settings for Flat and RIAA, and the above-mentioned owner's manual has several pages of commendably thorough EQ recommendations for various labels, large and small, plus two pages of very helpful tips on record labels and matrix numbers.

The Re-Equalizer's circuitry is built into a metal box 9.5" wide by 1.5" high by 5.5" deep, itself fastened to a rack-width (19" W by 1.75" H) panel of black-anodized aluminum, and the construction quality is remarkably good. Even before using it, I was impressed by the apparently high value offered by the Rek-O-Kut Re-Equalizer.

I've had time for only a brief audition so far, but nothing has shaken that good first impression. If anything, I'm as amazed by the Re-Equalizer's apparent noiselessness as by its obvious flexibility. It isn't a perfectly transparent thing, of course; even in Bypass mode, the Re-Equalizer adds a very slight veiling or "grayness" to the sound. But the Rek-O-Kut is effective, it's useful, and it's fun. It gave me a refreshing new perspective on the 1935 recording of Mahler's Symphony 2 by Eugene Ormandy and the Minneapolis Symphony Orchestra and Chorus—an interesting and thoughtful if way less than masterful interpretation—and I had a great time using the Turnover knob to play "now you hear it, now you don't" with the kick drums on a variety of old jazz records.

Designer Mike Stosich, who keeps the Rek-O-Kut company name alive with the blessings of its founder's family, offers a whole line of phono products through his company, Esoteric Sound, many of which are geared specifically toward 78rpm enthusiasts. Another of those is a downright essential accessory that sells for a mere $24, and which I'll describe in next month's column—along with more listening impressions of the Re-Equalizer, and an introduction to two or three other 78-friendly phono preamps. Stay tuned.

Sharks
Lately, I've stumbled across the websites of at least two record dealers who have some free advice for certain owners of 78rpm records: "Too bad, but none of the classical records in your collection are worth a dime: Nobody wants them. You should just throw them out—or, if you prefer, I could take them off your hands for a couple of bucks. As a favor to you, of course†.†.†."

I happen to be acquainted with one of the two men I've seen making that claim, and I have more respect for the bacteria in a box of Rid-X.

In the vintage guitar world, that sort of trade practice is called sharking. My first experience with it happened back in the early 1990s, just after I'd purchased a 1967 Fender Stratocaster for $1000: a very good but not unheard-of deal at the time. (Strat prices have, of course, gone up astronomically since then, as happened with a '54 hardtail that I owned and played for years; both guitars are now with other owners, I'm sorry to say.) Hoping to get an appraisal for insurance purposes, I brought the guitar to a vintage dealer in White Plains, New York, where I lived at the time. The shopkeeper's assistant opened the case, uttered a few tsk-tsk-tsks, and recited a litany of things he said were wrong with the guitar. He concluded by offering to take it off my hands for a few hundred dollars, to use as a "parts guitar"—unless, he added with a chuckle of condescension, I wanted to hold on to the guitar for "sentimental reasons."

Crushed, I almost fell for it. Instead, I took the Strat back to my apartment and looked up the number of Gruhn Guitars, Nashville's original vintage guitar salon. I got George Gruhn himself on the phone—a kindly, well-informed gentleman who gave his time freely and inquired about all of my Strat's various appointments. Satisfied that my guitar was completely original—and worth much more than I'd paid for it—he told me, "Son, the fellow at that store was tryin' to shark you, that's all there is to it!" (You can be darn sure I've given George Gruhn as much business as I could afford to over the years since: He remains the single most honest, reliable, well-informed man in that industry.)

The bottom line: Anyone who tells you that people aren't buying classical music on vinyl or shellac—especially shellac, a field in which mint originals by Ignaz Paderewski and Emma Eames have been known to command goodly sums—is a lying sack of shit. And that's being kind. If you have such records in your collection, then by all means, sell off a few if you must, but keep as many as you can: Listened to in your home with the appropriate playback gear, those records will do almost as much for your soul as the collected works of Robert Frost or a kiss on the cheek from a loving child. And that's saying a great deal.

Back to the source
Thorens TD-124 turntables have a way of finding me, and that's fine: I enjoy it when they do.

Today I'm in the midst of refurbishing another one: a late-1960s sample in much rougher shape than the one that has become my day-to-day player. This Thorens TD-124 needs new paint, too, so I've had to remove every part from the cast-alloy chassis and catalog it before cleaning it and storing it away in a little ziplock bag. I'm taking pictures as I go along, too: I no longer listen to the bad part of my brain that tells lies to the good part—things like, "Don't bother drawing a diagram, you'll remember where that part goes a month from now" and "When the lighting is just right, you look like you still have all your hair."

Digging deeper into the TD-124 left me with even deeper respect for the thing. Consider the bubble level that's built into the chassis: Whoever engineered the product guessed that the level might have to be replaced some day. So rather than just glue the little bastard in place, which is what most contemporary hind-end audio companies would do, Thorens milled a ¼" opening into the casting, just beneath the level. When the level needs to come out, just put a short hardwood dowel into the opening, tap the end lightly with a deadblow hammer, and pop: Out it comes like a tooth.

And that's not to mention the refinement of the mechanical linkage between the speed switch and the idler-wheel gantry. Or the reversible mirror "lens" assembly for the strobe viewer. (It can be set for either 50Hz or 60Hz mains current, with no need for additional parts.) Or the ingenuity of the eddy-brake system for fine-tuning platter speed, and thus pitch. All that in a product that sold in the US for only $99 in 1957.

A couple of industry bigwigs, including at least one person associated with the present-day Thorens organization, have expressed displeasure that I lavish so much attention on a discontinued product, ostensibly at the expense of current production. In light of the above, I'm not sure I can find in my heart a great deal of remorse.



Footnote 1: Another windfall: The variable-velocity encoding of high frequencies made it easier for the signal level to swamp the high-frequency surface noise that bedevils shellac.

Footnote 2: It's interesting to compare that range with the 500Hz–3kHz range in which acoustic recording technology was most effective.

Footnote 3: Rek-O-Kut, Esoteric Sound, 1608 Hemstock Ave., Wheaton, IL 60189. Tel./Fax: (630) 933-9801. Web: www.esotericsound.com.

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