Historical Product

The Ortofon SPU 90th Anniversary


In this cartridge, a one-piece body makes the direct connection between the generator system and the wooden housing, ensuring both a perfect rigid connection and extremely high internal damping. A nude elliptical diamond stylus graces the aluminum cantilever, representative of the legacy created by SPU's past, along with a black painted, grinded wood body. Also adding to the sonic performance of the SPU 90th Anniversary is nothing but the best internal coil wiring, comprised of silver-plated ultra high purity (6NX) copper wire, to ensure that each and every movement of the stylus is captured faithfully without loss. The internal terminal wiring is made of ultra high purity (6NX) silver wire with gold-plated terminal connectors.

A revolutionary customized Selective Laser Melting manufacturing technique

The mechanical structure of the SPU 90th Anniversary cartridge has also been re-engineered, as well as many of its internal assemblies. At the mechanical heart lies the , a revolutionary customized Selective Laser Melting (SLM) manufacturing technique in which micro particles are laser-welded together, layer by layer. This high technology and high precision process eschews traditional techniques to provide high rigidity and a body density resulting in the further reduction of unwanted resonances while still maintaining exacting figures for cartridge mass. 

SLM manufacturing also enables the consolidation of components to allow for a design devoid of unnecessary material. 

Field Stabilizing Element system and microassembly

Another first is the inclusion of the renowned Field Stabilizing Element (FSE) system, which consists of a small cylinder of conductive material placed strategically inside of the magnetic system. FSE guarantees that the force field within the system will remain stable at all times regardless of the moment of the armature.

This technology was first introduced by recently-retired chief engineer Per Windfeld in his widely acclaimed Kontrapunkt series. What this means in practical application is that not only will the FSE minimize dynamic and intermodulation distortion, but it also will allow for greater dynamics, absolute clarity, and depth of sound for truly awe inspiring sonic performance.

SPU 90th Anniversary technical data

Output voltage at 1000 Hz, 5cm/sec.    - 0,3 mV
Channel balance at 1 kHz  -   < 1 dB
Channel separation at 1 kHz   -  > 23 dB
Channel separation at 15 kHz  -   > 15 dB
Frequency range at - 3dB   -  20-30.000 Hz
Frequency response  -   20-20.000 Hz ± 2 dB
Tracking ability at 315Hz at recommended tracking force  -   80 µm
Compliance, dynamic, lateral  -   10 µm/mN
Stylus type   -  Nude elliptical
Stylus tip radius  -   r/R 8/18 µm

Tracking force range  -  2,5-3,5 g (25-35 mN)
Tracking force, recommended   -  3,0 g (30 mN)
Tracking angle   -  20°
Internal impedance, DC resistance   -  2 Ohm
Recommended load impedance   -  10 - 50 Ohm
Cartridge body material  -   Wood powder + Phenolic resin
Coilwire material   -  Silverplated Copper
Cartridge colour   -  Shiny Black
Cartridge weight   -   28 g