Ortofon 2M 78 Pre-Mounted Cartridge

Is the Ortofon 2M 78 Pre-Mounted Cartridge the Right Choice for Your 78 rpm Records?

Ortofon 2M 78 Pre-Mounted Cartridge is a mono cartridge designed for playing 78 rpm shellac records. It's aimed at collectors with an S-shaped tonearm who want straightforward installation and effortless replacement. Its differentiators are a 65 µm spherical stylus, a mono design within the 2M series, and a pre-mounted format that fits and swaps as one assembly.

How does the Ortofon 2M 78 Pre-Mounted Cartridge compare with other 2M models?

The Ortofon 2M 78 Pre-Mounted Cartridge is the 78 rpm model in Ortofon's 2M series. Hi-Fi World's Tony Bolton described it in April 2013 as a well-considered mono version of the 2M family. Ortofon splits 2M styli into three interchangeable groups: the 2M Red, 2M Blue and 2M Silver; the 2M Bronze, 2M Black and 2M Black LVB 250; and the 2M Mono and 2M 78. A 2M Red or 2M Blue owner can't fit a 78 stylus to their existing body.

The 2M Mono is the closest alternative. The Stylus 2M 78 fits the 2M Mono body, so a 2M Mono owner can play 78s by changing styli on one cartridge. The pre-mounted 2M 78 suits buyers who don't own a 2M Mono, or who'd rather keep a separate assembly for shellac than swap styli between formats.

Which turntables can use it?

This cartridge is intended for turntables with an S-shaped tonearm, which is the arm type Ortofon specifies for the pre-mounted version. The turntable needs a 78 rpm speed setting to play the shellac records the cartridge is designed for. Ortofon advises checking your turntable's manual or the manufacturer's specifications before buying. Turntables can have specific requirements for cartridge type, mounting style and tonearm design.

Which tonearm masses suit the Ortofon 2M 78 Pre-Mounted Cartridge?

The Ortofon 2M 78 Pre-Mounted Cartridge has a lateral dynamic compliance of 18 µm/mN, which Ortofon classes as moderate compliance. Compliance and total moving mass decide the system's resonance frequency. Ortofon's acceptable window is 7 to 12 Hz, and it recommends 10 Hz.

Ortofon's formula is F = 1000 ÷ (2π × √(M × C)). M is the mass of the cartridge, headshell and screws plus the tonearm's effective mass. Taking the 16.7 g pre-mounted weight as the cartridge-and-headshell portion of M gives these results:

• A 4 g effective-mass arm resonates at about 8.2 Hz.
• An 8 g arm resonates at about 7.6 Hz.
• A 12 g arm resonates at 7 Hz.

Arms heavier than about 12 g fall into the 6.5 to 7 Hz band. Ortofon says that band can be used without problems. Above roughly 16.5 g, resonance drops below 6.5 Hz, which Ortofon describes as questionable. Lighter S-shaped arms leave the most margin.

What phono stage does this mono cartridge need?

The 2M 78 is specified for a 47 kOhm load and 150 to 300 pF of capacitance. It gives a 4 mV output at 1 kHz and 5 cm/sec. Those figures match a standard moving magnet phono input. The capacitance range covers your phono stage and tonearm cable combined, so check both when matching. The cartridge's 350 mH internal inductance and 700 Ohm DC resistance are the electrical values behind those load recommendations.

How is it installed and set up?

The Ortofon 2M 78 is supplied already fitted, so installation comes down to attaching the assembly to your S-shaped tonearm. You then balance the arm and set tracking force. Ortofon specifies 1.6 to 2.0 g, with 1.8 g recommended. Hi-Fi World's review noted strong tracking at that 1.8 g setting. The tracking angle is 20°. Replacement follows the same route: the whole pre-mounted unit comes off the arm, and another goes on.

What stylus does the Ortofon 2M 78 Pre-Mounted Cartridge use?

The Ortofon 2M 78 Pre-Mounted Cartridge uses a spherical diamond with a 65 µm tip radius on an aluminium cantilever. Ortofon notes that the diamond is the only part of a cartridge touching the groove. Its shape governs how accurately the cartridge reads the groove. The 70 µm tracking ability at 315 Hz sets how far the stylus can follow lateral groove movement before it loses contact.

When the diamond wears, you replace it with the Stylus 2M 78 rather than the whole cartridge. Ortofon highlights the replaceable stylus as an ownership advantage of this cartridge design. The same replacement fits the 2M Mono, so a household with both cartridges can keep one spare stylus for either.