Benny Audio writes: “At the heart of a phono cartridge’s operation lies a simple yet fascinating phenomenon: electromagnetic induction, born from the vibrations of a coil relative to a magnet (in MC cartridges) or a magnet within a coil (in MM cartridges). Now, I’m not going to bore you with the basics of MM and MC cartridges—you can read up on that anywhere. Let’s skip ahead to the good stuff.
The generator sits at the end of the cantilever, with the stylus attached at the other end. The shape of the stylus tip is crucial, but that’s a topic for another day. As the stylus moves within the groove of a vinyl record, it wiggles left and right as well as up and down, according to the 45-45 stereo groove concept. To simplify: the left-right movement controls amplitude, while the up-down movement corresponds to the left or right channel.
This motion of the stylus makes the cantilever dance, and this dance is what generates the electrical signal we ultimately hear as music.
So, it turns out that the magic of a phono cartridge all comes down to vibrations—these are the unsung heroes of the sound we hear, the very essence of the cartridge’s function.
Since we are dealing with vibrations, the mass of the vibrating system (cantilever, generator) and the damping of their movement are crucial. The greater the mass, the more sluggish the movement becomes (note that, as it turns out, MC cartridges are heavier), which results in less dynamic and generally less detailed sound. On the other hand, we have damping forces like the magnetic field (thanks for the comment), which negatively affect the signal quality in the case of MM cartridges.
Another key player in the cartridge’s performance is the cantilever suspension, which, unfortunately, has a finite lifespan. Unlike other components, you can’t just replace this part, which is why cartridges come with a manufacturer’s recommended playtime (500, 1000, or up to 3000 hours in practice). For context, 1000 hours of play equates to roughly 1200 km if you calculate 20 minutes per record side = 400 meters of groove.
The suspension wears out, but the cantilever itself doesn’t. However, hold on—integral to the cantilever is the stylus. What’s its deal? The stylus is diamond-tipped, and compared to the vinyl grooves, it’s as tough as a knife cutting through butter. Yet, despite this hardness, the stylus does wear out. I had to change my view on this after examining photos of new versus worn styli. The wear, especially at the contact points with the record groove, was clearly visible on the used stylus. It’s also worth noting how tiny a portion of the stylus actually engages with the groove.
Beyond normal wear, the stylus can be damaged or severely dirtied. I’m sharing photos of a new stylus, a worn stylus, and a dirty vs. clean stylus with permission from Dr. Bogusław Ziębowicz, a fellow vinyl and music enthusiast.
Now, a bit of a side note: If the cantilever suspension wears out, why do people go to such lengths to revive heavily used cartridges, replacing cantilevers and styli? And why replace them with parts that the cartridge designer never intended? It’s like putting F1 racing suspension on an off-road vehicle. Or buying a car with a shot suspension but shiny new rims and tires. I know I’m stepping on toes here.
By now, it’s clear that the source of our audiophile pleasure—those analog vibrations—has a dark side. After generating the signal, there’s a ton of leftover energy that needs to go somewhere. According to the law of conservation of energy, it can’t just disappear. It might turn into heat or, you guessed it, more vibrations.
As cartridge prices climb, manufacturers pay increasing attention to the problem of excess vibrations. They use different body shapes and materials, and some even (though I disagree with this approach) employ dampers. All of this is to channel the excess energy from the cantilever’s motion properly. If this energy isn’t managed within the cartridge and its body, we risk dealing with unwanted vibrations—or worse, resonances, where vibrations spike suddenly at specific frequencies.
When these unwanted vibrations occur, they mix with the intended vibrations (from the record groove), leading to a distorted, resonance-tainted sound.
So, how do we ensure that no unwanted vibrations or resonances creep into the cartridge during playback? How do we make sure that the sound we hear is purely the signal from the record?
Tune in for the next installment to find out!