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Phono Stage article

The Ultimate Guide to Phono Stage

Without the right amplification and equalisation, vinyl cannot be played through a modern system. Here is a complete explanation of how a phono preamp works.

The Ultimate Guide to Phono Stage

A phono stage — also called a phono preamplifier — is the component that makes vinyl playback possible through a modern hi-fi system. Without one, the signal from a turntable cartridge is too quiet and too spectrally incorrect to be useful. This guide covers what the component does, how to match it to your cartridge, and the difference between built-in and standalone designs.

Signal Amplification and RIAA Equalisation

A cartridge on a turntable stylus produces a tiny electrical signal — around 1 to 5 millivolts for a moving magnet design, and as little as 0.1 millivolts for a moving coil type. This is far quieter than the line-level signal that an amplifier expects. A phono stage amplifies this output to line level. It also applies RIAA equalisation: vinyl records are cut with a standardised EQ curve that reduces bass and boosts treble during recording. The unit reverses this curve on playback, restoring the correct frequency balance. Both functions are essential — amplification without RIAA correction, or vice versa, produces unusable results.

Moving Magnet vs Moving Coil Inputs

The type of cartridge you use determines what kind of input you need. Moving magnet (MM) cartridges produce a relatively high output and work with a standard MM input. Moving coil (MC) cartridges produce a much lower output — some as low as 0.1mV — and require either a dedicated MC input with high gain, or a step-up transformer used in combination with an MM input. Most entry-level and many mid-range setups use MM; MC is preferred at the higher-performance end. Matching input type to cartridge type is the most critical compatibility check before purchase.

Built-In Phono Stage vs Standalone

Many amplifiers include a built-in phono stage. These are convenient but variable in quality — a budget amplifier's built-in circuit is typically less refined than a dedicated standalone unit at a similar price. A separate unit allows the electronics to be isolated from the main amplifier's power supply, which reduces interference and improves noise performance. For serious listening, a dedicated unit is the better long-term investment. For the buying decision in detail, see our buyer's guide. For new vinyl listeners, see our beginners' guide.

Frequently Asked Questions

Do I need one if my amplifier already has a dedicated input?

If your amplifier has a built-in phono input, you can use it without a separate unit. Whether an upgrade is worthwhile depends on the quality of the built-in circuit. Budget and mid-range amplifiers often include basic built-in stages that benefit from being replaced with a dedicated standalone unit. High-quality integrated amplifiers sometimes include genuinely competitive internal phono circuits.

What is RIAA equalisation?

RIAA equalisation is a standardised audio curve applied during vinyl mastering and reversed during playback. When a record is cut, bass frequencies are attenuated and treble frequencies are boosted. On playback, the process is reversed. This allows more music to fit on a side of a record and reduces the impact of surface noise. Any device designed for vinyl playback applies this correction.

What is the difference between MM and MC inputs?

MM (moving magnet) inputs are designed for cartridges that produce a higher output signal, typically 2–5mV. MC (moving coil) inputs are designed for cartridges with much lower output, sometimes as low as 0.1mV, and apply significantly more gain. Using an MM cartridge with an MC input produces an overloaded signal; using an MC cartridge with an MM input produces a signal that is too quiet.

How do I know which input I need?

Check the cartridge specifications — the output level is listed in millivolts. If it is between 1 and 6mV, you need an MM input. If it is below 1mV, you need an MC input. Some cartridges are described as high-output MC; these are designed to work with MM inputs. The cartridge documentation will specify.

Can a phono preamp improve the sound of a budget turntable?

Yes, within limits. A better standalone unit will reproduce the signal the turntable produces more accurately. It cannot compensate for a poor cartridge or a poorly set-up turntable, but if those elements are adequate, upgrading the electronics can produce a meaningful improvement, particularly in noise floor and tonal accuracy.

How much should I spend?

Entry-level standalone units start at around £30–£60 and offer a meaningful step up from typical built-in amplifier circuits. Mid-range units at £100–£300 provide good MM and MC performance. Beyond that, the returns become more marginal and a matter of taste. For most systems, the £50–£200 bracket delivers excellent results relative to cost.

About James Harrison

James learned guitar in a cold Leeds practice room and taught himself to fix his own gear when he couldn't afford to replace it. That DIY instinct became a lifelong obsession with how instruments are built and why some just feel right. He writes buying guides and gear features for players who want the honest version, not the sales pitch.

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