Ortofon SPU Gold Reference
The SPU Gold Reference is the member of Ortofon SPU family of 1989
Its major features include an Ortofon Replicant 100 stylus, 99.9999% pure copper armature windings and leads, and a slightly modified damping system.
These improvements have made it possible to reduce the tracking force and obtain a more linear frequency response. Sonically, the Gold Reference is still a genuine SPU of which Mr. Gudmandsen would be proud.
In order to satisfy the requirements of owners of vintage equipment, the SPU Gold Reference was introduced in two different housings with identical electrical specifications. The GM housing had the same dimensions as standard shells and fitted into Ortofon’s classical RKG 309 and RMG tonearms.
The SPU Gold Reference requires a tonearm which is rigid, devoid of resonances and able to counterbalance a cartridge weight of 32g in this GM version.
The choice of Stylus Profile
The actual shape of the contact point of the diamond stylus on the groove is vitally important for accurate sound reproduction, as is the profile of the contact area. To allow tracking of the high frequency information, particularly in the critical inner turns of the groove, it is mandatory to employ a slim stylus profile.
The very first generation of SPU cartridges was equipped with spherical styli. As soon as elliptical shapes could be produced, such a stylus type was incorporated in the design. The original SPU Gold was one of the first cartridges to employ a true elliptical stylus ensuring the lower record wear.
Like the other Ortofon top-of-the-line cartridges, the stylus for the SPU Gold Reference has been designed and produced in close collaboration with Ortofon Swiss diamond supplier, Fritz Gyger. Its shape is closely aligned to the profile of the original cutting stylus and its quality is the very highest possible. The front facet of the Ortofon Replicant 100 stylus is flat, which allows maximum space for the stylus to move freely in the groove. The rear contact surface of the diamond has three facets to reduce stylus volume (and thus the mass) while maintaining the strength and integrity of the diamond. The contact area is highly polished in order to achieve a perfect radius. And the stylus profile along the 90° V-track of the groove is shaped to make the highest degree of contact ever made possible by a playback stylus - surpassed only in this respect by the cutting stylus itself.
Cantilever, Armature and Damping
With the selection of the Ortofon Replicant 100 stylus, we have chosen the diamond whose geometry permits tracking of even the highest-frequency groove information.
Following the SPU tradition, the cantilever of the SPU Gold Reference is cylindrical and made from aluminium which has been gold plated by means of a metal evaporation process to match the other metal parts of the cartridge.
The relatively large, square armature ensures a more than adequate output voltage of 0.2 mV plus, while the low number of windings make the cartridge a genuine low-impedance design, featuring an internal resistance of only 3 Ohm. A further improvement of the sonic qualities is obtained by means of 99.9999% pure copper for the windings and the litz wire leads in the GM housing.
One of the secrets behind the characteristic Ortofon SPU sound is the rubber bearing which dampens the cantilever movements. Consequently, this bearing is of exactly the same type as in the standard SPU cartridge. In order to improve the frequency linearity, the suspension wire has been made a little longer.
We offer Special Repair Service for SPU Gold Reference models »
|Output voltage at 1000 Hz, 5cm/sec.
||> 0,2 mV
|Channel balance at 1 kHz
||< 1 dB
|Channel separation at 1 kHz
||> 25 dB
|Frequency range at - 3dB
||20-20.000 Hz +2.5 dB/0 dB
|Tracking ability at 315Hz lateral
||> 70 µm
|Compliance, dynamic, lateral
||Ortofon Replicant 100
|Stylus tip radius
||r/R 5/100 µm
|Tracking force range
||2.5 - 3.5 g (25-35 mN)
|Tracking force, recommended
|Internal impedance, DC resistance per channel
|Recommended load impedance
||> 10 Ohm
|Cartridge body material