Photo below: Former Ortofon CEO Eric Rohmann (Left) presents the Danish Queen Margrethe II's merit medal to Robert Gudmandsen for his technical achievements. Image courtesy Ortofon.
The SPU’s moving-coil design is deceptively simple according to Ortofon: "A generator comprising two low-impedance coils, wound with very fine copper wire and crossed in such a way that the two walls of an LP's stereo microgroove generate two discrete signals with maximum separation.” Yet it birthed a movement in high fidelity whose boundaries are still being pushed to this day by companies like Koetsu, Dynavector, Shelter, and Audio Technica (to name a few) – all of which feature moving-coil configurations that owe much to Gudmandsen’s groundbreaking work in the forties and fifties. The story of the SPU can be traced to 1918 when engineers Axel Petersen and Arnold Poulson founded the Electrical Phono Film Company in Copenhagen, Denmark. The pair sought to develop a system able to synchronize the recording of audio to film – five years later they premiered their first ‘sound film.’ The method at the time involved running two synchronized projectors simultaneously, one with images and one with audio. This led to later technological advances allowing sound and images to be captured on the same strip of film. Gudmandsen, who started his career in radio engineering, was recognized as an up-and-coming talent by Poulson who hired him in 1941 to help design an amplifier and condenser microphones at Electrical Phono. Petersen and Poulson, not content with their success in the film industry, wanted to branch out and challenge themselves further.
With Gudmandsen’s help, the company designed a gramophone amplifier and cutting head in secrecy during WWII. The cutter head’s oscillation registration was increased from 5kHz to 14kHz – an unprecedented level of resolution that no existing pick up could reproduce. So in 1948, Gudmandsen designed a mono cartridge capable of handling such high specifications – one of the first moving coil pick ups with integrated headshell – the type AB, which debuted with a new tonearm. The type AB was followed by the type A and C pick ups (A– consumer version, 7g tracking weight, C– professional version, 3g tracking weight). These models featured a two-pin (mono) bayonet mount with a circular locking-collet connection. The motor consisted of a vertical coil and pole-plate assembly and short, stubby aluminum cantilever which allowed for tip movement to be converted to an electrical signal incredibly close to the groove. The design facilitated an accurate frequency translation of up to approximately 20kHz. The type AB, A and C were sold predominantly to the broadcast industry and also turntable manufacturers such as EMT who used these mono cartridges and their accompanying tonearm exclusively for decades. While other individuals and companies registered patents on variations of the moving coil principle before Fonofilm A/S did, it was the type AB, A and C that became widely accepted.
There have been many versions of the SPU since it was introduced in 1958. Many are improvements on previous models, but they never shy away from this smooth, rich, textural sound. I feel the SPU is Ortofon’s platform to explore these qualities over all else.”
Photo above: Early Ortofon type AB cartridge. Image courtesy Ortofon.
The next 10 years saw Electrical Phono change its name to Fonofilm A/S, and then Ortofon (Greek for correct sound). Gudmandsen and his engineering team continued to refine the initial magnet/pole structure along with variations on the diamond stylus profile being used. Further changes to the motor assembly, its orientation and alignment foreshadowed the blueprint for the stereo pick up. Gudmandsen credited the cartridge’s unique sound qualities to the use of nickel-plated 0.11mm piano wire to secure the cantilever via a minuscule rubber O-ring. The SPU we know today was brought to market following the introduction of the stereo LP in the fall of 1958, about a year after Ortofon released its moving-coil, stereo-head cutter. There were now two Bakelite body styles with a four-pin (stereo) bayonet mount; the type A became the SPU-A (spherical stylus), and the SPU-AE (elliptical stylus). These were joined by the SPU-G featuring a larger whale-shaped housing (22mm longer) which was later accompanied by a shorter tonearm to accommodate the type G body. The larger G housing was required to fit both the cartridge assembly and internally fitted step-up transformer (SUT) on certain models (type GT for spherical with SUT, GTE for elliptical with SUT). The cartridges were weighted at 32g to maintain uniform effective mass across the G range whether or not the SUT was included in the headshell.
Photos below: (Left) Vintage Ortofon SPU advertisement. Current Ortofon SPU #1 cartridge. Images courtesy Ortofon.
Over the next several decades, differences in the materials used for the motor assembly occurred amid supplier and design changes, or as environmental considerations demanded. The headshell, for example, which was originally formed from Bakelite (a mixture of formaldehyde, hydrochloric acid and phenol), was switched to a ground wood, resin-impregnated composition sometime in the late-eighties. The SPU range also slimmed-down to three basic models during this time span. The type E (elliptical stylus), the G (spherical stylus), and the T (with or without headshell step-up transformer). By the time the late sixties hit, the SPU G model evolved into what became known as the reintroduced SPU Classic. Throughout the eighties, nineties and noughts specialized, limited-edition SPU models were introduced to celebrate anniversaries or special events. These include the SPU Gold in 1980, the Gold Reference in 1989, the SPU Meister in 1992, the SPU Royal in 1998, the SPU 90th Anniversary in 2008, an SPU Collector Box in 2011, the current SPU #1 and S models in 2016 and the SPU Wood A in 2017.
Photos below: Audio Engineer and vintage loudspeaker-system designer Devon Turnbull. Images courtesy Isa Saalabi.
Interest in the SPU came back to North American shores within the last decade or so, carried on an echo from the hi-fi impact of fifties gear that hit the Far East – most notably Japan – 40 years ago. The intensity in which Asian-market audiophiles pursued the SPU, and with it the Garrard 301 turntable, Western Electric valve amplifiers/horn systems, and Altec speakers – all designs from the ‘20s to the ’50s – radically altered the tenor of the hobby in these countries. It was in Tokyo, while working on his clothing company Nom De Guerre, that artist, designer and audio engineer Devon Turnbull was first exposed to a sound system fronted by an SPU. Turnbull credits the system with altering his trajectory in high fidelity. “It was about 15 years ago, when I was first spending time with audio importer Koji Wakabayashi, and his main system. The front end was an SPU with Ortofon RF 297 tonearm on an EMT 927 turntable. A Western Electric 59B amp was driving a full blown original WE Mirrophonic speaker system,” said Turnbull. “Of course, this was an extreme system and impossible for me at the time to speak to the character of any one individual component, but as a whole the sound was so rich with tonality, texture, depth and dynamics that it set me on an entirely new path.”
Turnbull said despite this experience, there was no definitive moment when he realized the SPU would become his cartridge of record. “When I got my first SPU my main cartridge was a Denon 103R, another iconic moving coil. But, following the experience with Wakabayashi, I made a definite move away from a ‘perfect’ sound, in favour of a more charming analog sound. The SPU is not a transparent component, like a CD player or a lot of contemporary high end gear. It’s unapologetically vinyl sounding and I think more than any other component represents this vintage sound while also being absolutely high end, and professional.” Turnbull said he had gone through many cartridges prior to his SPU exposure. “I had several versions of the Denon 103, a Shelter 901, GE VRII... I’m sure some I’m not thinking of, and a long history with moving magnet designs by Shure, Nagaoka, Ortofon, etc.” He puts his current collection at roughly a dozen SPU. “There have been many versions of the SPU since it was introduced in 1958. Many are improvements on previous models, but they never shy away from this smooth, rich, textural sound. I feel the SPU is Ortofon’s platform to explore these qualities over all else.”
Turnbull recommends buying a new version of the SPU if you’re unfamiliar with vintage gear and the work that can be involved in refreshing it. “Assuming that you have a standard bayonet mount tonearm that can balance an SPU, get one of the current production #1 A or E depending if you have a preference on the tip profile. If your system is otherwise quite modern, go with the S version, as it has the most vintage character. If your system is lacking in detail and sparkle maybe the E is for you. Pair with some Altec 4722 transformers as a step up and you will have a very iconic front end.”
Photo above: A few of the vintage SPU type A and G cartridges in Turnbull's collection. Image courtesy Isa Saalabi.
Picking up an Ortofon SPU that’s vintage is not a difficult proposition, but does involve performing basic research into a reputable online seller, or possibly from a physical store (bricks and mortar shops carrying SPU from different periods in their production history are hard to come by outside Japan). A quick search on eBay brings back dozens of hits from sellers in Japan with excellent feedback, so there your options are only limited to what SPU variant you’re after (type A or G) and from what era. Like buying anything used, there are risks cautions Turnbull. “It’s difficult to tell in photos or even real life if the cartridge has been rebuilt – Ortofon does not do rebuilds (it simply replaces the entire assembly except for the body), so it begs the question, who rebuilt it?” He added that some SPU in his collection are ‘mystery rebuilds.’
Another issue according to Turnbull is the build variation of cartridges direct from the factory over the intervening decades, with different cantilever and diamonds offering the only real visual identifiers for dating their construction. “There are only really two to three sources for those parts from what I understand,” he said. Turnbull has a technician in Japan who specializes in rebuilding SPU. “He’s matching as closely as possible the older parts, but ultimately you have to judge a cartridge – rebuilt or original – with your own ears.” His two most coveted SPU span more than 30 years between them. “I have two favourites,” said Turnbull. “The first is an SPU A/E, 1988 production with the Bakelite headshell. It was gifted to me by Wakabayashi. I believe it is the very same one we were listening to the first time I visited him. The other is the current production Wood A, which is my reference cart at the moment.”
Photo above: SPU type A Meister edition. Image courtesy Mikio Hasui.
Regardless of the vintage one ends up choosing to start their SPU journey, be it a current production model or an example from previous decades, the Ortofon SPU has been a benchmark in the audio world for more than 70 years (if you include the first Fonofilm type AB, A and C mono iterations). For decades it helped deliver musical and spoken word broadcasts to hundreds of millions via radio broadcasts all over Europe, Asia, Africa and North America before migrating into audio hobbyists homes. Since it first appeared in the forties and fifties on broadcast-specified turntables like the Garrard 301/401, EMT 927/930 – which are all now considered holy grail audiophile decks – the Ortofon SPU’s industrial beginnings have traced an arc of success that resonates to this day within modern cartridge manufacturers designs. Owning an SPU is very much about owning a piece of history, not whatever the marketing machine is hyping as the latest and greatest. It's about aligning oneself with the sonic aesthetics of an earlier era in music reproduction, an era when listening was all about enjoying the sound, not analyzing it.