For some inexplicable reason Denmark had become a hotspot for phono system innovation following World War II. Bang & Olufsen's tangential turntables during the 1970s come to mind, but even earlier, Ortofon's pioneering of moving coil cartridge technology wins top spot for advancing the state-of-the-art for years to come. Today Ortofon is the leading manufacturer of phono cartridges with an impressive sales base, roughly divided between HiFi and DJ models. Yet, Ortofon has remained true to its roots. Its classic SPU line has remained in production since 1959 when the first SPU (an acronym for stereo pick-up) came to market. The SPU's longevity in an age where few models survive more than a few years serves as a testimonial to the line's appeal to music lovers worldwide. Robert Gudmandsen, also known as Mr. SPU, is the father of the Ortofon large pickup program. His original SPU model, introduced the low coil impedance concept as the basis for an extended high-frequency range. The Royal N is said to provide sonic performance similar to that of the SPU Royal GM series, but is sold without the integrated headshell unit to allow integration with a variety of modern tonearms.
A significant technical advance over other SPU
models is the addition of Ortofon'sReplicant 100 stylus. A nude diamond is
polished to closely mimic the shape of the cutting stylus. This stylus provides
a small scanning radius as well as a large vertical contact surface and can be
therefore categorized as a line contact type. The mother of all such styli was
the Shibata, introduced by JVC circa 1972 for reproduction of quadraphonic
recordings. Technically, the stylus is part of a transducer system, but there's
room for artistic interpretation. It's helpful to think of the stylus as a
ballerina dancing along the record groove. It does all the work of retrieving
groove modulations, and the line contact type does the best job of that, since
it resolves extreme treble detail while safely accommodating a few grams of
vertical tracking force (VTF) without vinyl damage. Careful attention has also
been paid to the guts of the cartridge. The moving coils are gold plated silver
and all wiring is high purity 6-nine copper.
You can't go wrong following the factory's setup
instructions. As a starting point for vertical tracking angle (VTA), the top of
the cartridge should be parallel to the surface of the record. Obviously, it's
always helpful to work with a tonearm that provides fine control over VTA, as
does the Ref 313VTA, as you may wish to tweak the VTA slightly from this
starting position. The optimal setting is often variable from record to record,
but as a default setting I ended up lowering the rear of the cartridge about
half a degree below parallel. I was also satisfied with the recommended VTF of
3.0 gram after experimenting with a couple of VTF settings. Tracking was just
fine at this setting for all of my favorite LPs. I should mention that Ortofon
was kind enough to send along their DS-1 Stylus Force Gauge ($159). It's simple
to use, allows force measurement at a height corresponding to a nominal LP
thickness, and provides a resolution of 0.1 gram. It's now my favorite digital
gauge and I highly recommend it for serious vinyl aficionados.
Ortofon specifies a minimum cartridge loading of
100 Ohm, and generally speaking a 1:10 step-up transformer ahead of a MM phono
stage wired for the industry standard 47 kOhm input impedance will provide an
adequate reflected impedance load for the SPU of about 470 Ohm. However, A 1:30
step-up will only yield about a 50 Ohm reflected impedance. Having recently
adopted the Pass Labs XP-25 phono stage as a reference, affords me the
flexibility to readily change cartridge gain, and both capacitive and resistive
loading via dials on the front panel. How easy is that? I was therefore able to
experiment with several resistive loads. Settings between 100 and 500 Ohm worked
well, but I didn't care as much for the 1 kOhm setting which for some reason
didn't sound as smooth. Note that most of the listening sessions were conducted
at a setting of 160 Ohm.
In contrast, the SPU sounded much more tube like.
It projected an superb feel for hall ambience together with a nicely fleshed out
depth perspective. Massed voices were clearly resolved, though I preferred the
image solidity generated by my old standby, the Symphonic Line RG-8 Gold, a
custom version of the van den Hul Grasshopper. Factor in suave and sweet
harmonic textures and you realize that the SPU is first and foremost about the
midrange. It was a very special midband indeed that crackled with dramatic
tension. Microdynamics were beautifully nuanced, convincingly communicating the
music's passion and emotional content. Transients unfolded with bold dynamic
strokes while remaining faithful to a natural musical fabric. The sheen and
shimmer of a violin's upper overtones was faithfully reproduced without
gratuitous edginess or brightness. Female voice was given full scope of
expression while retaining excellent timbre accuracy. And there was plenty of
boogie factor to propel the music forward. The SPU never disappointed when it
came to rhythmic drive – never a dull moment with this cartridge in the chain.
As with any front end component, its perceived
sonic character is greatly influenced by the associated gear. Obviously, the
tonearm, turntable, and phono preamp are of paramount importance, but the
speakers and power amplification contribute as well to the overall impression.
That's why the SPU saw duty with several speakers and power amplifiers. The
consensus that emerged from all of those listening sessions was that the SPU
lacked a bit in terms of bass impact. I wouldn't go so far as to characterize it
as "bass lite," simply because the lower midrange possessed a convincing big
tone character. It simply eased up a bit on the gas pedal when it came to
reproducing tympani and kick drum. The SPU fell a bit short relative to the RG-8
and certainly with respect to the Dynavector XV-1s with its killer bass range.
The other frequency extreme also sounded a tad shy at times, but I should
emphasize that the impression was akin to a middle of the hall perspective. The
net effect was to slightly reduce perceived treble extension and transient
speed. And as a result, the focus shifted to the midrange, as harmonic textures
took on a slightly softer and warmer disposition.
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