Ortofon - 2M Mono MM Phono Cartridge

A true mono cartridge with a strapped output, so mono records play properly on an ordinary stereo system — no mono switch, no special phono stage.

This is a dedicated mono design, not a stereo cartridge with its channels bridged at the plug. Ortofon describes the mechanism precisely: the 2M Mono uses a strapped output to deliver the same signal from both sets of pole pins, which removes any need for mono-specific equipment and makes true mono reproduction possible on any stereo playback system. Channel separation and channel balance are published as not applicable, because there are no separate channels to separate.

The advantage over playing a mono record with a stereo cartridge is real and Ortofon is specific about it. A mono cartridge is unaffected by vertical movement — including the pinch effect, where the stylus is pushed upward in narrow grooves — and produces a single signal sent to both channels. A stereo cartridge on a mono record instead contributes crosstalk, noise, phase errors and distortion, which Ortofon characterises as an unstable and partially fuzzy sound.

The stylus is a nude spherical of R 18 µm on an aluminium cantilever, which Ortofon calls an optimal solution for playing mono microgroove LPs. That phrase is doing real work, and it is worth being straight about the boundaries. By Ortofon’s own guidance, records from around 1950 with bottom groove radii of 15 µm or larger want a spherical 25 µm stylus, which Ortofon does not offer in the 2M range. At the other end, modern narrow-groove mono reissues cut at around 60 µm suit a line contact profile better. This cartridge is aimed squarely at the broad middle: ordinary mono microgroove LPs.

Everything else is standard 2M practice. 4mV output into a 47k ohm load, 1.8g recommended tracking force, the same threaded half-inch body, and the same stylus assembly fitting as the 2M 78 — which means one body and two styli will cover both mono LPs and shellac.

Features

• True mono design with a strapped output — both sets of pole pins deliver the same signal
• Works on any ordinary stereo phono stage; no mono switch or mono-specific equipment needed
• Insensitive to vertical modulation, including the pinch effect in narrow grooves
• Nude spherical diamond, R 18 µm, on an aluminium cantilever
• 4mV output into a standard 47k Ω moving magnet input
• Shares its stylus fitting with the 2M 78 — one body, two styli covers mono LPs and shellac
• Threaded half-inch mounting plate; two screws, no nuts
• Also available in 2MR form for Rega-style tonearms, premounted on an SH-4 headshell, and as a bottom-mount Verso

Specifications

• Type: True mono moving magnet cartridge with strapped output
• Output Voltage: 4mV at 1kHz, 5cm/sec
• Channel Balance at 1kHz: Not applicable — Ortofon publishes N/A
• Channel Separation at 1kHz: Not applicable — Ortofon publishes N/A
• Frequency Range: 20Hz – 22,000Hz at −3dB (Ortofon 2M brochure; dropped from the current product page)
• Frequency Response: 20Hz – 20kHz, +3 / −1dB
• Tracking Ability at 315Hz: 70 µm at recommended tracking force
• Compliance: 18 µm/mN, dynamic lateral
• Stylus Type: Nude spherical
• Stylus Tip Radius: R 18 µm
• Cantilever: Aluminium
• Tracking Force Range: 1.6 – 2.0g (16 – 20mN)
• Recommended Tracking Force: 1.8g (18mN)
• Tracking Angle: 20°
• Internal Impedance, DC Resistance: 700 Ω
• Internal Inductance: 350mH
• Recommended Load Resistance: 47k Ω
• Recommended Load Capacitance: 150 – 300pF
• Cartridge Body: Polymer and aluminium
• Colour: Black / White
• Cartridge Weight: 7.2g
• Replacement Stylus: Stylus 2M Mono
• Stylus Interchange: Belongs to the Mono / 78 group. The same body accepts the Stylus 2M 78 with its R 65 µm spherical tip, so a single cartridge can serve both mono microgroove LPs and shellac 78s
• Intended Records: Mono microgroove LPs. By Ortofon’s own guidance, early 1950s mono pressings with bottom groove radii of 15 µm or larger call for a spherical 25 µm stylus, which Ortofon does not make in the 2M range, and modern narrow-groove mono reissues are better served by a line contact profile
• Mounting: Half inch (1/2″) mount. The 2M threaded mounting plate is 3mm thick, so no nuts are needed. Ortofon supplies a pair of M2.5 screws with a 5mm thread length, to be used with headshells up to 3.5mm thick. Ortofon warns against overtightening and against aluminium screws, which can seize in the threaded holes
• Stylus Life: Ortofon rates its styli at up to 1000 hours with proper care, and notes that DJ use — scratching and back-cueing — should be reckoned at about 500 hours at most. This is a general figure across the range rather than a per-model specification
• Cleaning: Ortofon specifically warns against propyl alcohol and other cleaning fluids, which can seriously damage the diamond cement and the suspension system
• Design: The 2M series was developed with the Danish industrial design house Møller Jensen Design. Ortofon does not publish the year the series launched
• Origin: Ortofon A/S of Nakskov, Denmark. Ortofon states that all its cartridges are designed and crafted in Denmark
• Warranty: Ortofon Inc. covers cartridges bought from an authorised US dealer for one year against defects in workmanship and materials, and excludes expendable items — which on any normal reading excludes the stylus. Note that Ortofon’s own webshop terms quote a two-year warranty instead; a US dealer purchase falls under the one-year terms
• Not Published: Any vertical compliance, vertical rejection or vertical-modulation sensitivity figure to quantify the vertical-insensitivity claim; coil system and coil wire material, which Ortofon leaves blank for this model; the compliance measurement frequency; any warning against playing stereo records with it
• Note: Ortofon’s own product page for this cartridge carries a section about the Beatles mono box set which actually describes the 2M Mono SE — a discontinued Shibata-tipped model, not this spherical one. We have not reproduced it. Ortofon also publishes no warning against playing stereo records with a mono cartridge; where retailers carry one, it is not a manufacturer statement