Moving coils put out a tiny fraction of the signal that a moving magnet does, so require a much larger gain in the phono preamp stage. High-end Vinyl purists usuallly stick their nose up at mm cartridges, stating that mcs produce a more detailed, far superior sound quality, but at a large price difference. Personally, the mm cartridges I've had sound just fine to me. I'm sure TLS Guy has a wealth of information on the differences.
Thanks for the invitation Geno. This question has not come up quite this way before.
Record playback cartridges fit into four broad categories.
1). Moving coil.
2). Moving Magnet.
3). Moving iron, often referred to as variable reluctance.
4). Piezo/ceramic types.
Now the moving coil types come as low and high output types.
The principle is that there are two coils attached on armatures at 90 degrees attached to the stylus. These coils are suspended between a powerful magnet. As the coils move, electricity is generated and fed from the moving coils to the pre amp for amplification.
High output types have more turns of wire, and have a higher source impedance and can be connected directly to the phono input, if it has enough gain.
The more usual low output types have less turns and a very low source impedance. Unless the preamp also contains a moving coil preamp stage, then a step up impedance matching transformer is required, or a moving coil high gain preamp stage.
The high output types have heavier coils and therefore compliance and trackability are not quite as good as low output types.
Moving magnet types have two small magnets attached to the stylus at a 90 degree angle. The magnets are placed in stationary coils and as the magnets move electricity is generated in the stationary coils. Output is higher, and can be connected to 47 K ohm RIAA equalized phono inputs.
The moving iron variable reluctance types have pieces of ferrous metal in place of the above magnets, moving in coils wound round a powerful magnet.
The best example of this type are the Decca ffss series which became the Decca London cartridges. These cartridges have outputs similar to moving magnet types.
In crystal and ceramic types the stylus tries to deform material that generates a voltage when deformed. These cartridges of historic interest now were on budget turntables. They produced a high output, requiring 1 meg ohm input impedance and produced a response that was the inverse of the RIAA curve and did not need equalization. 100 mv outputs and higher were possible.
So what's the deal?
Probably the most important fact is that only in the moving magnet and crystal types is the stylus is user replaceable. For all other types the cartridge has to be completely rebuilt.
Now the moving coils and moving irons are much more costly to manufacture.
Both these types require powerful magnets and are heavier. Therefore they require tone arms of higher mass to keep the cartridge tone arm resonance on the right place.
Because of the lead out wires, moving coils do not generally have as good compliance and trackability as moving magnets.
Also when using moving coil or moving iron cartridges, you must make sure that the turntable platter is non ferrous, otherwise the magnet will drive the stylus hard in into the record. Music Hall turntables for instance have ferrous platters and can not be used with these type of cartridges.
Moving magnet cartridges have low mass generally and require low mass tone arms for the resonance to be in the right place for best trackability.
So why bother with moving coils? The reason has to do with the hysteresis of magnetic materials. With the moving magnets types there is a finite degree of hysteresis distortion. The amount depending on the quality of the cartridge. This also applies to the moving iron. Also the moving coils frequently have a slightly rising response above 10 kHz, which the loony crowd interpret as "air".
To my mind the real downfall of the moving coil, apart from expense and no user replacement styli, is there increased mass, and above all their relatively poor compliance and trackability.
I personally think that compliance and trackability are very important cartridge parameters. In other words I would far rather have a cartridge/arm combination that does a good job on most records, rather than one that plays a few superbly.
To close be aware, that phono cartridges come in a huge range of quality.
All things being equal, there is a chasm in the performance of a cartridge under $100 and one on the $500 to $800 range.
My personal favorite of all time is the Shure V15 xmr. This is sadly not in production, and anyone who has them is wisely holding on to them.
The best current alternative is the top of the line Ortofon MM, the
2M Black.