MM vs MC Phono Preamps: Matching Your Cartridge

What the Two Cartridge Types Need

Moving magnet (MM) and moving coil (MC) cartridges are the two main types of magnetic phono cartridges. The difference lies in how they generate the electrical signal. An MM cartridge has the magnet attached to the cantilever, while an MC cartridge has the coil attached. This changes the output voltage and the impedance the phono preamp sees. Your phono stage must be designed for the cartridge type to deliver correct gain and loading.

Most entry-level turntables come with an MM cartridge and a built-in phono preamp that is matched to it. If you later upgrade to an MC cartridge, you will need a phono stage with MC capability. Learn more about the cartridge types to see which one fits your system.

Gain: Why MC Needs More

Gain is the amount of amplification the phono preamp applies to the cartridge's tiny signal. MM cartridges produce a relatively strong signal, so they work with the modest gain found in most built-in phono stages. MC cartridges produce a much weaker signal, especially low-output MC designs. To bring that signal up to line level, the phono preamp must provide significantly more gain.

Many phono stages have a switch for MM and MC modes, or separate inputs, so you can match the gain to your cartridge. If the gain is too low, the volume will be weak and you may hear background hiss when you turn it up. If it is too high, you risk overloading the preamp. The phono preamp gain article explains how to set it correctly.

Loading: Impedance and Capacitance

Loading refers to the electrical load the phono preamp presents to the cartridge. This load affects the frequency response and damping of the cartridge. MM cartridges are typically loaded with a high impedance, often by a capacitance value. MC cartridges are loaded with a low impedance, usually a resistive value. The correct loading can prevent a bright or rolled-off sound.

If your preamp has adjustable loading, you can fine-tune it to your cartridge. The recommended loading is usually specified by the cartridge manufacturer. For a deeper look, see phono cartridge loading.

Noise: The Signal-to-Noise Equation

Noise matters because it competes with the music signal. MM cartridges have a higher output, so they are less demanding on the phono stage's noise floor. MC cartridges have a lower output, so the phono stage must have very low self-noise to achieve an acceptable signal-to-noise ratio.

In practice, MC phono stages are often built to a higher standard with low-noise components. The tradeoff is that MC systems can be quieter in absolute terms, but the gain needed is higher, and any hum or hiss is amplified more. If you are considering an MC setup, pay attention to the noise figure of the phono stage.

Built-In vs. External Phono Stages

Many turntables now include a built-in phono preamp. Most of these are MM-only, with fixed gain and loading. That works fine for an MM cartridge, which is what comes on most new turntables. If you plan to use an MC cartridge, you will likely need an external phono preamp that can handle MC gain and loading.

Some external phono stages offer both MM and MC modes, with switchable loading. If you already have a separate phono stage, you can choose a turntable without a built-in preamp, which often gives you a cleaner signal path. The built-in phono preamp vs external comparison covers the pros and cons.

How to Choose Your Phono Stage

First, identify the cartridge type on your turntable. If it is an MM cartridge, a basic phono stage with MM support is sufficient. If you have an MC cartridge, you need a phono stage with MC support and appropriate gain. If you are planning to upgrade your cartridge later, consider a phono stage that offers both modes and adjustable loading.

Also think about your system: a built-in preamp is convenient, but an external unit gives you more control and often better noise performance. For a step-by-step approach, read how to choose a turntable and the phono preamp vs receiver input guide.

Quick Comparison

Here is a summary of the key differences between an MM and an MC phono stage. This table shows how they compare across the most important aspects.

A Note on Record Care

No matter which cartridge you choose, proper record care keeps your vinyl in good shape. The Library of Congress recommends handling grooved discs by the edge and label areas only and storing them upright in a cool, dry environment. This reduces wear and keeps playback clean. See their guidelines for more details.

What to pick for your use

Questions

Can I use an MC cartridge with a built-in phono preamp?

Most built-in phono preamps are designed for MM cartridges only. They do not provide enough gain or the correct loading for MC cartridges. You need an external phono stage with MC support, or a built-in unit that explicitly offers an MC mode.

How do I know if my turntable has an MM or MC cartridge?

Check the cartridge body for markings. Most affordable turntables use MM cartridges. If the model number includes 'MC' you likely have a moving coil, but many low-output MC cartridges are aftermarket upgrades. The manufacturer's documentation will state the type.

What happens if I use the wrong phono stage?

If you use an MM phono stage with an MC cartridge, the output will be very low and you will likely hear excessive background noise. If you use an MC stage with an MM cartridge, the signal may be overamplified, causing distortion or clipping.

Do I need a separate phono preamp for MC?

Yes, unless your receiver or turntable has a specific MC input. Separate phono preamps often offer adjustable gain and loading, which is essential for getting the best performance from an MC cartridge.

What is the difference between low-output and high-output MC?

High-output MC cartridges put out a signal close to MM levels, so they can be used with an MM phono stage, though the loading may not be ideal. Low-output MC cartridges require a dedicated MC phono stage with much more gain.