Phono Accessory Reviews

Miyajima Laboratory Kotetu Mono Cartridge
If you were shopping for records in the early years of stereo—or if you've bought many older, used records since—you probably recall the stern warning on the back of many early stereo records, that they should be played only with a stereo or stereo-compatible cartridge. The warning was necessary because mono cartridges were made to only move laterally—left and right—while the grooves on a stereo record are vertical as well. Older mono cartridges were designed so that the cantilever and stylus could move freely from side to side, following the groove, but they were very stiff in the vertical direction to make them more robust. If you try to play a stereo record with a true-mono cartridge with very low vertical compliance, you could damage your records. Instead of moving up and down hills and valleys, the stylus would dig in like a pile driver and try to burrow through.

To avoid this problem, some modern mono cartridges are little more than rewired stereo cartridges, the left and right coils connected together to provide mono output. Those cartridges have plenty of vertical compliance.

Miyajima (footnote 4) argues that to get the best sound from mono records, you need a true, dedicated mono cartridge, one that's impervious to the stylus's vertical movement.

If you think of mono records as being old, scratchy, noisy things, that's probably because you've been playing them with stereo cartridges. A scratch on a mono record damages both top edges of the groove wall, resulting in vertical movement of the stylus. A mono cartridge is effectively deaf to vertical motion, so the sound of the scratch will be barely audible. You can play some pretty beat-up mono records with a mono cartridge, and they will usually sound remarkably quiet and free from distortion.

Miyajima offers four models of mono cartridge, of which the Kotetu ($655) is the most affordable. The Kotetu is available in two versions, one with a 4.0 mil spherical stylus for playing 78s, and a microgroove version for LPs with a 0.4 × 0.7 mil elliptical stylus. With the more expensive Zero and Infinity models, you also get a choice between two microgroove styli depending on whether you play mostly early original or more modern mono LP pressings. For the Kotetu, Miyajima has chosen a compromise they feel works well with any mono LP.

Installing the Kotetu proved straightforward; its low vertical compliance makes it insensitive to tracking force. Miyajima specifies a wide range of 3–4.5gm; I settled on the recommended value: 3.5gm.

Miyajima cartridges have always used through-holes for their mounting screws, making them a bit fiddly to attach because you have to screw on those tiny nuts; at least the Kotetu doesn't require extra-long screws as Miyajima's wood-body models do. In the case of the Kotetu, it's easy enough to insert the screws from below, holding the nut on top of the headshell with a finger until the nut catches a thread.

The Kotetu is a low-output moving coil cartridge with internal impedance of just 4 ohms. I set the gain on my Parasound JC 3 Jr. phono preamp to 60dB and dialed the load impedance to about 75 ohms. Despite its pure-mono suspension, the cartridge has four output pins; connect them all and, in a stereo system, you'll be sending identical mono signals to both channels.

Whether mono recordings are best heard through a single speaker or through both speakers of a stereo setup is a discussion for another day. I used two speakers for all my listening.

I'm young enough that almost all the music I grew up listening to was in stereo. For many years, I avoided mono recordings because they lacked some of the sonic qualities I craved. But over the years, my musical interests have expanded to include more music made before the late 1950s, especially jazz.

While you can still find 60-year-old classical records in great shape, the same is rarely true for jazz. Most jazz-record fans in the 1950s and '60s seem to have really hammered their records; probably they played them on equipment that wasn't kind. On a stereo system with a stereo cartridge, they can be hard to listen to. But play a seemingly trashed mono record with a true mono cartridge and it's remarkable how clean they can sound.

Case in point: an original, deep-groove copy of Hampton Hawes's first album on the Contemporary label, Hampton Hawes Vol.1: The Trio (Contemporary C3505). Visually, I would have graded it VG–, but with the Kotetu, the sound was clear and focused with just a little unobtrusive surface noise. I was particularly struck by how well the Kotetu tracked this heavily worn record, with none of the usual insecurity or breakup in Hawes's piano sound.

One of my favorite mono albums is Stravinsky's 1961 recording of his chamber piece L'Histoire du Soldat suite with the Columbia Chamber Ensemble (Columbia Masterworks ML 5672, footnote 5). This recording is also available in stereo, but in many ways, the mono sounds better. My copy was sealed when I bought it, so the record is pristine, with surfaces that are practically silent when played with the Kotetu. I heard startling dynamics from the snare drum, an impressive sense of weight and power in the plucked bass line, and lucidity in the violin tone that quickly became addictive.

To hear how well the Kotetu could extract a full symphony orchestra for playback in a single channel, I played Julius Katchen's December 1955 recording of the first Tchaikovsky piano concerto (Ace of Clubs ACL 63, a 1959 reissue of Decca LXT 5164). The first thing that struck me was the amount of depth I was hearing. We tend to think of mono as delivering a single central spot of sound, but this is false. A natural orchestral recording still has the acoustics of the recording space embedded within, and even without left and right stereo cues, this allows you to position the various musicians within the soundstage, front to back. On this record Katchen's piano is clearly sitting out in front of the rest of the orchestra, with the strings positioned between the piano and other sections like winds and brass. The clarity and tone of the piano is superb here, with no muddling of Katchen's supple right-hand lines backed up by a solid foundation from his left. I was knocked out by the overall quietness and lack of surface noise, as I was with other older pressings. Once you eliminate the vertical noise information, these records play as if they're fancy 180gm audiophile pressings.

Going back to some of my less-than-wonderful-condition mono records, I pulled out an original Capitol LP pressing of Frank Sinatra's In the Wee Small Hours (Capitol W 581). I was able to compare it to a later pressing, probably from the 1970s. Despite being in worse condition visually, the earlier pressing sounded far more engaging, with a sense of body and richness to the sound of Sinatra's voice and a greater sense of envelopment from the string orchestra. As with the Hampton Hawes record, I was astonished by how quiet the surfaces sounded and by the Kotetu's overall ability to play music with such focus and clarity.

I requested the Kotetu because, despite having installed several of the more expensive Miyajima Zero and Infinity monos, I have never actually laid hands on the more affordable Kotetu. What's more, even though I have set up dozens of mono cartridges, until the Kotetu arrived, I had never lived with one myself. Now that I've experienced at length just how much music a true mono cartridge can dig out of a tired old groove, I won't be making that mistake again.

If you have a significant collection of mono records, this is something you need to check out.

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Footnote 4: Miyajima Laboratory, 4-3-25, Chayama, Jounan-Ku, Fukuoka City, Fukuoka, 814-0111 Japan Web: miyajima-lab.com. US distributor: Robyatt Audio, 513 Dotters Corner Rd., Kunkletown, PA 18058. Tel: (855) 762-9288. Email: info@robyattaudio.com. Web: robyattaudio.com.

Footnote 5: The cover credits the album to the Columbia Symphony Orchestra, but a smaller group—presumably members of the orchestra—plays on the L'Histoire du Soldat suite.