MC vs MM!?

Moving coil cartridge good, moving magnet bad? Not so fast... By Vertere Acoustics... "Interesting to read, in the coverage of a recent amplifier launch, were the comments of surprise that it ‘only’ had a moving magnet phono stage. After all, the commentators declared, wouldn’t anyone buying such an amplifier be using a clearly superior moving coil design?"

One-minute recap here: both designs handle the same task, which is turning the movement of the stylus in the groove into electrical signals, using the electric motor principle of the relative movement of magnets and coils of wire. As the names suggest, in a moving magnet cartridge the magnets are attached to the cantilever carrying the stylus, as move relative to fixed coils; in the moving coil, the magnets are fixed in place, and the coils move relative to them.

Here at Vertere, we rather like moving magnet cartridges: if the mechanics are done correctly, they can do a very good job of translating the movement of the stylus into electrical impulses, so the ‘upgrade’ from Moving Magnet to Moving Coil isn’t always inevitable.

But there’s another consideration to think about: moving coil cartridges generate a lot less output voltage than moving magnet designs, meaning that their signal needs more gain in the phono stage for an amplifier’s line input to be optimum. The lower output also makes the signal more prone to noise and interference. 

The delicacy of the whole enterprise means moving coil cartridges, and the amplification they require, are usually exacting to design and make – and that means more expensive. So buy an inexpensive Moving Coil cartridge, or rely on a cheap phono stage with MM/MC switching, and you may be stepping sideways, not upwards. That’s not to say there aren’t good inexpensive MC cartridges or good MC phono stages but equally there are some great MM cartridges at sensible prices

Oh, and there’s one final practical point: while most moving magnet cartridges have user-replaceable stylus assemblies, the design of moving coils precludes this. So if your stylus becomes worn, or damaged, with a moving coil you may have to replace the whole cartridge, whereas with a moving magnet design it’s a simple two-minute job to change styli – and you can often upgrade your cartridge with a better stylus assembly from the same manufacturer too