Moving Magnet vs Moving Coil Cartridges

The difference between MM and MC phono cartridges, what each needs from your phono stage, and how to choose.

Every phono cartridge turns the stylus's tiny movements into an electrical signal using a magnet and a coil. What differs is which part moves.

Moving magnet (MM)

A small magnet is attached to the cantilever and moves between fixed coils. MM cartridges produce a relatively high output (around 3–6 mV), suit almost any phono input, and usually have a user-replaceable stylus. That makes them economical to run.

Moving coil (MC)

Tiny coils are attached to the cantilever and move within a fixed magnetic field. Because the coils are light, the moving assembly can be very low in mass, which many listeners hear as greater detail and speed. The penalty is low output, often 0.2–0.5 mV, which needs a high-gain phono stage or a step-up transformer. The stylus generally can't be replaced by the owner: worn cartridges are rebuilt or exchanged.

High-output MC and other variants

High-output moving coils use more coil turns to reach MM-like output levels. Moving-iron and induced-magnet designs are further variations, with characteristics of their own.

Loading and gain

• MM: usually 47k ohms, with capacitance (including cable) affecting the treble.
• MC: commonly 100–1,000 ohms, depending on the coil's internal impedance. Follow the maker's advice and fine-tune by ear.

Choosing

A good MM cartridge on a well-set-up deck is a fine place to start, and stylus replacements are inexpensive. Moving coils make most sense once the rest of the vinyl chain (arm, phono stage, set-up) can reveal what they offer.