Secrets Q & A

Moving Magnet vs Moving Coil

Question
I bought a new turntable but am still trying to decide on the cartridge. Should I get a moving magnet (MM) or moving coil (MC) cartridge? What price range should I consider assuming I have mid-priced components in my audio system?

- Tony M
Phoenix, AR

Answer:
This is a great question. At SECRETS we would like to review more cartridges, but they are difficult to obtain for review, possibly because reviewers are loath to do the work of de-installing and re-installing cartridges. It might also be because cartridge manufactures know that setup is key and they don’t trust reviewers to do it properly.

A general note about cartridges in general - like other audio components the best cartridge for you will depend somewhat on the specifics of your system but unlike most other components, it also depends on the type of music you listen to. It is an unfortunate fact of life that the ‘transducer’ components of a system are still the hardest to make. A transducer converts from one form of energy to another. In the case of most modern home audio systems the only transducers are the speakers (converting electric energy to mechanical) and we have seen how often speakers are mentioned as the most important component to get right. Often this means the component to spend the most money on (although speaker bang per buck has been going up steadily for many years now).

If you have a turntable, first, you are brilliant. Second, you now have another transducer in your system and the cartridge’s job of converting mechanical energy to a tiny amount of electrical energy is critical. And it is hard to get a cartridge that can do everything for a small amount of dollars. Unlike speakers, it seems like cartridge prices have been increasing of late, such that there are only a few choices for less than a grand. Still, with a decent table and a cartridge and a clean record you can easily beat all but the best digital front ends.

So, a moving magnet (MM) cartridge accomplishes the conversion by connecting the vibrating needle to a set of magnets that then vibrate in close proximity to coiled wire while a moving coil (MC) has the needle vibrate coiled wire in close proximity to fixed magnets. Historically, MC cartridges produced about one tenth to 1/100th the amount of energy as a MM, so MM was a better choice for those on a budget as the phono stage did not have to be as sensitive, or as immune to noise and vibrations. For use with an MC cartridge, there is usually an extra gain stage in the phono preamplifier. Fortunately MC design has caught up, and ‘high output’ MC cartridges are readily available.

Now here is what I consider a key difference that is not often mentioned. In order to suspend the heavy magnets, MM designs use a rubber grommet between the needle/cantilever/magnet structure and the cartridge body. This grommet also becomes part of the sound or course, and that might be ok. But, it wears out. Two years is a typical number that is given, I know I’ve heard a difference after three years. This happens whether you are playing records or not.

So, given all of the above, a high output MC design is definitely the way to go in my opinion. The sound from an MC is faster and more detailed than a comparable MM. A good MM can sound very sweet and lush but is not worth the extra maintenance for me. For MC, consider Dynavector for the best all-around, especially if rock or electronic music is on the playlist. Audio-Technica is a little less expensive and also good though you might find some colorations at the extreme low end of that line. Denon’s are highly reviewed but I haven’t heard them. If you decide to stick with MM, Grado has the definitive line and they all sound good.

After you have your cartridge, you can tune further with your choice of mat but that is the subject for another article.