fonostage

A fonostage, also known as a phono preamplifier or phono stage, is an electronic device that boosts the very weak signal from a phono cartridge to a level that can be handled by a standard line-level amplifier or receiver. The signal produced by a turntable's cartridge is significantly lower in voltage than that of other audio sources like CD players or streaming devices. Additionally, the signal requires specific equalization according to the RIAA (Recording Industry Association of America) curve.

Without a fonostage, the output from a turntable would be too faint to be audible through most audio systems and would lack the proper tonal balance. Many integrated amplifiers and AV receivers include a built-in fonostage, often labeled "PHONO" on the input selector. However, audiophiles often opt for external, dedicated fonostages, believing they offer superior performance due to better component quality, power supply design, and noise reduction.

These external units can vary greatly in complexity and price. Some are simple, low-cost devices designed to get a turntable working with a modern system, while others are high-end components featuring adjustable gain, impedance, and capacitance settings. These adjustable parameters allow users to fine-tune the fonostage to perfectly match the characteristics of their specific phono cartridge, optimizing sound quality. The primary function remains the same: to amplify and equalize the turntable's signal.