Ortofon SPU Royal GM MKII Moving Coil Cartridge

Buying the Ortofon SPU Royal G MKII: Is It the Right SPU for Your Tonearm?

Ortofon SPU Royal G MKII is the integrated-headshell SPU for owners of classic detachable-headshell tonearms who want a line-contact stylus in an SPU body. This Ortofon SPU moving coil cartridge is the only SPU fitted with the Nude Replicant 100 diamond, which it pairs with Electrum coils and a revised damping system. Ortofon launched the Royal GM and Royal N in 1998 to mark its 80th anniversary, and the SPU Royal GM MkII carries that design forward. It's a low-output design, so it suits systems that already include a high-gain step-up transformer or an active MC phono stage.

What Makes the Ortofon SPU Royal G MKII Different From Other SPUs?

The Ortofon SPU Royal G MKII is different because Ortofon changed three parts of the classic SPU generator: the stylus, the coils and the damping.

The Replicant 100 diamond has an r/R 5/100 µm line-contact profile, where other stereo SPUs use spherical or 8/18 µm elliptical tips. Ortofon explains that finer cuts gain a larger contact area with the groove wall and trace it more closely, getting nearer to the shape of the cutting stylus that made the record. The diamond is nude rather than bonded to a metal shank, which lowers its mass. Lower tip mass lets the stylus respond faster to groove modulations and reduces distortion. That's the mechanism behind the open, detailed reproduction Ortofon attributes to the Royal.

The Electrum coils are wound with gold-plated silver wire. Ortofon specifies this material to carry armature movement to the output without colouration. The Classic, Synergy, #1 and Wood A models use high purity OFC copper.

A slightly modified damping system reduces vibration inside the cartridge body. Ortofon states that this raises linearity and allows a lower vertical tracking force.

The published figures reflect these changes. The Royal G MKII's frequency response of 20 Hz–20 kHz +1.5/-0 dB is the narrowest tolerance in the SPU range. Its channel separation exceeds 25 dB at 1 kHz and 20 dB at 15 kHz. No other stereo SPU reaches 20 dB at 15 kHz, so left and right signals stay more distinct in the treble.

Which Tonearms Will It Fit?

This cartridge is a G-type SPU, with the generator and headshell built as one unit. It mounts directly into tonearms that take detachable headshells, such as the SME 3009 and SME 3012, and into other arms with the same "universal" mount. You don't need a separate headshell, and there's no cartridge-to-headshell fitting to carry out. The integrated body won't fit a fixed-headshell arm or a standard half-inch headshell. For those set-ups, Ortofon makes the SPU Royal N with a half-inch adaptor. The complete G unit weighs 30 g, so confirm that your arm's counterweight can balance it.

Will the SPU Royal G MKII Suit Your Tonearm's Effective Mass?

The SPU Royal G MKII is a very low-compliance cartridge, rated at 8 µm/mN dynamic lateral compliance. Ortofon places cartridges in the 5–10 µm/mN band in this class and pairs moderate-to-low compliance designs with moderate-mass tonearms.

Ortofon's resonance formula is F = 1000 ÷ (2π × √(M × C)), and it targets a cartridge/arm resonance of 7–12 Hz. M is the combined mass of cartridge, headshell, screws and arm effective mass. Use your arm's effective mass without a headshell, because the Royal's 30 g already includes one. On its own, that mass gives a resonance of about 10.3 Hz. An arm with 10 g effective mass brings it to about 8.9 Hz, and a 15 g arm brings it to about 8.4 Hz. Total system mass can reach roughly 65 g before resonance drops below 7 Hz. An arm rated at 10 g or less, which Ortofon classes as low mass, lands inside the window because the SPU's own weight makes up most of the total.

What Phono Stage or Step-Up Transformer Does It Need?

The Royal G MKII is a 0.2 mV moving coil cartridge, measured at 1 kHz and 5 cm/sec. Ortofon presents the 0.5 mV Synergy G as the SPU that relaxes the need for a high-gain transformer or active pre-amplification. That places the Royal at the demanding end of the range for gain. Its internal impedance is 7 ohms, the highest of the stereo models in Ortofon's SPU brochure, and Ortofon recommends a 100 ohm load. Check both figures against your step-up transformer or MC input specification before you buy.

How Do You Set Tracking Force on This Cartridge?

This cartridge is specified for a recommended tracking force of 3.0 g, within a range of 2.5–3.5 g. That's 1.0 g lighter than the 4.0 g used by the Classic, Meister Silver, #1 and Wood A. Owners moving from one of those models should re-balance the arm rather than keep the old setting. The tracking angle is 20°, matching the rest of the range. At 3.0 g, Ortofon quotes a typical tracking ability of 60 µm at 315 Hz.

What Kind of System Is the Ortofon SPU Royal G MKII Built For?

The Ortofon SPU Royal G MKII is a stereo cartridge for LP playback through a classic tonearm. Ortofon notes the SPU's strong following among listeners whose systems combine vintage valve equipment with horn or reflex loudspeakers. The Royal fits that kind of system once the gain stage is in place.

Mono collectors should look to the SPU Mono GM MkII or Mono CG models for those records. A mono cartridge produces a single signal and ignores vertical stylus movement. That removes groove pinching effects and cuts audible noise from dust and wear.

Should You Choose It Over Another SPU?

This model is the SPU to choose when stylus profile and measured linearity matter more than output level. The other SPUs suit different priorities.

The SPU #1 S and E are Ortofon's entry points for SPU newcomers, with spherical or elliptical styli and copper coils.

The Classic G MkII and Classic GE MkII keep the original recipe, with nude spherical or elliptical tips.

The Meister Silver GM MkII uses 6N silver coils. Ortofon raised its output to 0.3 mV to widen compatibility with transformers and MC preamplifiers.

The Synergy G suits systems with limited gain, given its 0.5 mV output and 10–50 ohm load.

The SPU Wood A has a Japanese beech housing with Urushi lacquer, and it needs the APJ-1 adaptor to reach standard GM length.

If your phono stage meets the gain needs set out above, the Royal G MKII is the one SPU that combines the integrated headshell with a line-contact stylus.

What Has It Kept From the Original 1958 SPU?

This cartridge is a direct descendant of the stereo pick-up Ortofon launched in 1958, which engineer Robert Gudmandsen played a principal part in developing. It keeps the SPU's original visual design and the original elements of its magnetic circuit. That circuit descends from a generator of two low-impedance coils, crossed so that each wall of the stereo groove produces a discrete channel signal. The stylus, coil and damping upgrades described above sit around that unchanged core. The body is a ground wood and resin composite in shiny black.