Analog Corner #284: Air Tight PC-1 coda phono cartridge, Zesto Andros Allasso step-up transformer

Something's definitely happening at the house of Yoshio Matsudaira. The legendary gentleman, whom I've never met or corresponded with, manufactures cartridges for his own brand, My Sonic Lab, as well as for others, including Air Tight. Over the past few weeks, more than a few readers have asked me to review or at least listen to the latest My Sonic Lab cartridge, the Platinum Signature. It's been described to me as having a faster, more open, less burnished sound than previous My Sonic Lab models. Based on my time with Air Tight's new PC-1 coda moving-coil cartridge ($8500, footnote 1), this may now be the sound of all cartridges made by Matsudaira. But that coda in its name gives me pause—will this be Air Tight's final cartridge? I hope not!

Air Tight began designing and marketing MC cartridges more than a decade ago, with the first PC-1, which combined low internal impedance with high output voltage, two characteristics that seemed both at odds with each other and nearly impossible to achieve: low internal impedance is usually the result of fewer turns of wire on the coil, and usually, the fewer the turns, the lower the output voltage.

Thanks to more powerful neodymium magnets and improved design efficiencies, cartridges from many different manufacturers now achieve low internal impedance and relatively high output, often without resorting to ferrous coil formers that can help increase the output but add mass, which reduces the responsiveness. What Matsudaira uses as a material for the former in the PC-1 coda isn't specified, nor is the makeup of the coil wire—or much else.

The lower an MC cartridge's internal impedance, the more current it can produce. Cartridges of low internal impedance are therefore ideal for use with current-amplifier type phono preamplifiers, such as the CH Precision P1. These circuits don't produce an ultrasonic peak in need of damping, so no resistive loading is needed.

The PC-1 coda's internal impedance is a super-low 1.7 ohms, and its output is relatively high at 0.5mV/1kHz. Its boron cantilever is fitted with a semi-line-contact stylus measuring 3 by 30µm, which should be somewhat less critical of stylus rake angle (SRA) than are some of the more radical styli.

The PC-1 coda's top plate is made of the same A7075 alloy, aka Extra Super Duralumin, of high-strength aluminum used in the far more costly Opus-1 cartridge that I reviewed a few years ago because Air Tight says it produces "less sound coloration."

The body of the PC-1 coda is made of A6063, an alloy of aluminum, magnesium, and silicon, and has a 50µm-thick base coating of nickel that in turn is plated in chrome, all for "deeper sound resolution" and "sharper and speedy lows and clearer soundstage" than the original PC-1s. Air Tight has also fine-tuned the suspension, to produce more cleanly defined images and better overall soundstaging. (I'm paraphrasing a cumbersome English translation from the Japanese.)

The PC-1 coda's channel balance is specified as "within 0.5dB/1kHz," and my review sample met that specification. The cartridge's channel separation isn't specified, but I measured 27dB and 26.5dB, with the headshell parallel and the cantilever perpendicular to the record surface. As I've come to learn, these separation numbers are at best approximate, though the balance figure is accurate. With the tonearm approximately parallel to the record surface, the SRA was 92°. In other words, this is a well-built cartridge.

The cartridge weighs 12.7gm, and the recommended vertical tracking force (VTF) is 2.0–2.2gm. At 2gm, the PC-1 coda couldn't get past the 50µm-peak track on the Ortofon Test Record. At a VTF of 2.2gm it could cleanly negotiate the 60µm peak (track 11), but it literally slid off the 70µm peak (track 12). In short, the PC-1 coda's tracking abilities are only moderately good, even for what I imagine is a moderately low-compliance MC. I say imagine because Air Tight doesn't specify the cartridge's compliance. However, I didn't have time to break in the cartridge for 40 or more hours; I'll report next time on what extra hours of use do, if anything, for this cartridge's tracking abilities. I chose to publish the review now rather than wait another month because, after using the PC-1 coda for only a few hours, I found that it exceeded, by a wide margin, my expectations for a Matsudaira-built cartridge's high frequencies.

I know that many people love Matsudaira cartridges, be they from Air Tight, My Sonic Lab, or TechDAS, and especially for the same reason that Lyra's discontinued Olympos cartridge has so many loyal fans: for their burnished, smooth, sophisticated—in a word, polite—upper octaves. But I insist on more sizzle with my steak.

The PC-1 coda combines the smoothness on top and in the mids that Air Tight fans love and expect, with some of the sizzle and air—that is, more sharply drawn and better-defined high-frequency transients—that you get with cartridges from Lyra, Ortofon, and some other brands.

The PC-1 coda's sound was enjoyable right out of the box, producing from the Herbert von Karajan-Berlin Philharmonic set of Beethoven symphonies (Deutsche Grammophon 104301/8) silky, delicate, but not overly romantic strings, properly burnished brass with appropriate bite, and a sumptuous soundstage set somewhat farther back than where the Ortofon MC Century or Atlas SL put it.

Images were pinpoint precise and well-focused, just as the PC-1 coda's one-sheet said they'd be. Despite its trackability performance with the Ortofon Test Record, the PC-1 coda cleanly tracked every record I played, including challenging vocal sibilants.

An old standby, Mel Tormé and Friends: Recorded Live at Marty's, New York City (2 LPs, Finesse W2X 37484), was taped in what sounds like a modestly sized cabaret. It sounded as good as I've ever heard it, Tormé's voice floating well focused and precisely and three-dimensionally against a "black" background, just a hint of upper-midbass accentuation giving it a convincing realism that leaner cartridges miss.

Just left of Tormé, Mike Renzi's piano also benefited from this slightly generous midbass voicing, without losing any of the upper keyboard's transient clarity or harmonic correctness—as did Jay Leonhart's double bass, its transients presented with all rhythmic intent preserved. Best of all, the sound of Donny Osborne's cymbals had a transient clarity, "sizzle," and surrounding air that I don't recall hearing from even the Opus-1.

The PC-1 coda is the best-balanced PC-series cartridge from Air Tight that I've heard, and it sounded as good with amplified rock as it did with pianist Vladimir Ashkenazy performing Beethoven's Piano Concerto 3, with Georg Solti conducting the Chicago Symphony Orchestra, recorded by Kenneth Wilkinson (UK LP, Decca SXLG 6594-7). This recording demonstrated to me that the Air Tight's extra kiss of midbass helped and did not hinder the piano's timbral balance and its spatial definition in front of the orchestra.

The Air Tight PC-1 coda is a masterfully voiced, low-coloration cartridge that worked well with all musical genres, but especially well with acoustic music. Let's hope its name doesn't prove prophetic!

Zesto Audio Andros Allasso step-up transformer
Just about everything in audio involves a controversy or two—and amplifying the typically low output of a moving-coil cartridge is no exception. It's a topic we've covered in previous issues, but with so many newcomers to this old technology, it's worth repeating. (But note: This discussion ignores those relatively few phono preamps that are based on current-amplification rather than voltage-amplification technology—another controversy!)


Simply put, the goal is to boost an MC cartridge's low voltage output, which usually ranges between 0.1mV and 0.5mV, by about 20dB. That boost brings the output more in line with that of a typical moving-magnet cartridge (ca 4mV). That can be accomplished either electronically, with an outboard gain stage called a head amp, or passively, via a step-up transformer (SUT). Each has advantages and disadvantages. Head amps have wide bandwidth, and give the user the ability to independently set gain and load impedance. On average, a good head amp is far less expensive than a good SUT. The disadvantages of head amps are noise, and distortion that increases with frequency.

SUTs, on the other hand, are entirely passive devices that require no power, but their basic simplicity doesn't mean that producing a great-sounding SUT isn't difficult, and thus costly. An SUT's distortion decreases as the frequency rises, and SUTs are essentially noiseless, with flat frequency response. (In practice, however, that flatness can be maintained only when the load is optimized for the particular cartridge used.)

Footnote 1: Air Tight, A&M Limited, 4-35-1 Mishimae, Takatsuki-city, Osaka 569-0835, Japan. Tel./Fax: (81) 72-678-0064. Web: US distributor: Axiss Audio, 17800 S. Main Street, Suite 109, Gardena, CA 90248. Tel: (310) 329-0187. Fax: (310) 329-0189. Web:

PeterPani's picture

This is the first time I can follwo the calculation of ratio and loading, so I am able to calculate the right windings for my (unusual types of) cartridges.
Q: with the Zesto, did your calculated values give the best sound results or did you end - after trial and error - with other switsch positions?
(the Yuko Mabuchi Trio I got on r2r)