Ortofon SPU Classic G Mk II Stereo Cartridge

Description

Ortofon’s SPU cartridges have long been cherished for their musical prowess, remaining resolutely old-fashioned in terms of weight, low compliance and heavy tracking force.  Have a read about the 60 year history of the SPU on Ortofon’s website here.   While there are SPU variants that can be used in tonearms having fixed headshells, most SPU models come with integrated headshells, now fashioned from ‘ground wood and resin’.  So, to use an SPU, you pretty much have to use a tonearm with a removable ‘SME’ type headshell connector, but fortunately most of the tonearms that we like and sell fall into that category.

The SPU Classic GM MkII is an SPU-style Moving Coil cartridge with a spherical stylus profile, for the playback of both early and modern stereo. Output is 0.2mV, so it needs to be played through a MC phono amplifier, or via a suitable MC step up device or transformer (SUT), and we recommend Sculpture A’s Mini Nano SUT with 1:26 gain ratio.

Ammonite Audio Inspection and Testing Policy

Please note that we inspect and briefly test each Ortofon SPU cartridge before sending out to the customer, so we do cut Ortofon’s factory seal on the packaging.  Visual inspection is just to confirm that the cantilever and tip are correctly fixed and aligned.  Our listening test involves setting the SPU up with recommended VTF and with the tonearm level, then briefly listening to outer and inner tracks of a known LP.

Technical Data

Output voltage at 1000 Hz, 5cm/sec. – 0.2 mV
Channel balance at 1 kHz < 1 dB
Channel separation at 1 kHz  > 20 dB
Channel separation at 15 kHz  > 10 dB
Frequency response – 20-20.000 Hz + 3/- 3 dB
Tracking ability at 315Hz at recommended tracking force *)  60 µm
Compliance, dynamic, lateral – 8 µm/mN
Stylus type – Nude Spherical
Stylus tip radius – R 18 µm
Tracking force range – 3.0-5.0 g (30-50 mN)
Tracking force, recommended – 4.0 g (40 mN)
Tracking angle – 20°
Internal impedance, DC resistance – 2 ohm
Recommended load impedance  >10 ohm
Cartridge body material – Ground wood and resin composite
Coilwire material – High Purity Copper (OFC)
Cartridge colour – Matte black
Cartridge weight – 30 g