Noise in MC Systems Explained: Where It Comes From and How to Reduce It

Why noise is more common with moving coil cartridges

Moving coil cartridges produce extremely low output voltages, often between 0.1mV and 0.5mV. Because the signal starts so small, it must be amplified far more than a moving magnet signal.

This high amplification makes MC systems inherently more sensitive to noise introduced anywhere along the signal path.

Types of noise you may hear

Hiss

Hiss is broadband noise caused by electronic amplification. It is most noticeable when gain is high or when the phono stage has a high noise floor.

Hum

Hum is usually a low-frequency tone related to mains power (50Hz or 60Hz). It is commonly caused by grounding issues or electromagnetic interference.

Buzz

Buzz often indicates radio-frequency interference or poor shielding, particularly near power supplies or digital equipment.

The role of gain in noise performance

Gain amplifies both signal and noise. In MC systems, excessive gain can raise the noise floor to audible levels.

Correct gain matching is critical: too little gain forces later stages to amplify noise, while too much gain amplifies noise at the phono stage itself.

Phono stage noise floor

The noise floor of a phono stage defines how much inherent electronic noise it produces.

High-quality MC phono stages use low-noise components, short signal paths, and careful power supply design to minimise noise.

Why step-up transformers can be quieter

Step-up transformers increase voltage passively, without adding electronic noise.

By boosting the cartridge signal before it reaches an MM phono stage, transformers often deliver lower perceived noise than high-gain active MC stages.

Cartridge output and noise sensitivity

Lower-output cartridges require more gain and are therefore more noise-sensitive.

Grounding and hum issues

Improper grounding is the most common cause of audible hum in MC systems.

• Ensure the turntable ground wire is connected
• Avoid multiple ground paths
• Keep signal cables away from power cables

Cable quality and shielding

Because MC signals are extremely small, cable shielding matters more than cable cost.

Short, well-shielded cables reduce the chance of interference entering the signal path.

Loading and perceived noise

Incorrect cartridge loading can exaggerate noise by altering frequency response.

Excessively high or low loading may make hiss or hum more noticeable even if noise levels are unchanged.

Power supply interference

Switch-mode power supplies, routers, and digital devices can introduce noise through electromagnetic radiation.

Physical separation between phono stages and digital equipment is often more effective than changing components.

When noise is not the phono stage

Noise is often blamed on the phono stage when the real cause is cartridge output mismatch, excessive gain, or grounding errors.

System-level diagnosis is essential.

Practical steps to reduce MC noise

• Use the lowest gain that provides adequate volume
• Match gain to cartridge output
• Ensure correct grounding
• Keep cables short and well-shielded
• Separate phono equipment from digital sources

What “silent” MC playback really means

No analogue system is completely silent. The goal is not zero noise, but noise that is inaudible during music playback.

Properly set up MC systems should be quiet at the listening position, even if faint hiss is audible with volume maximised.

Final thoughts

Noise in MC systems is not a flaw—it is a challenge that must be managed. With correct gain, careful grounding, and sensible system layout, moving coil cartridges can deliver exceptionally clean and dynamic playback without intrusive noise.