Unlike other Hi-Fi sources, the signal produced by a turntable's cartridge is both extremely quiet and shaped according to a specific equalisation curve (known as the RIAA curve), applied during record manufacturing to fit more music onto a disc. A phono stage performs two essential jobs: boosting this weak signal to a usable level, and applying the correct reverse equalisation to restore accurate tonal balance before the signal reaches your amplifier.

Some amplifiers and turntables include a phono stage built in, but a dedicated external phono stage typically offers noticeably better performance, since it can be optimised specifically for this single, critical task rather than sharing space and budget with other circuitry in an integrated design. This is particularly true for higher-end cartridges, especially moving-coil types, which often require more specialised phono stage support.

If your current system relies on a basic built-in phono stage, upgrading to a dedicated external unit is one of the most effective ways to improve overall vinyl playback quality, often delivering an improvement comparable to upgrading the cartridge itself.