Phono preamp

A phono preamp takes the very small electrical signal generated by a cartridge and boosts it up to line level, the standard signal strength that regular amplifiers, receivers, and powered speakers expect from any other audio source. It also applies RIAA equalization to restore the correct tonal balance.

Turntables need this step because a cartridge's raw output is far too weak and tonally skewed to sound right plugged straight into a standard line-level input. Some turntables include a built-in phono preamp with a switch to bypass it, some receivers and amplifiers have a dedicated phono input with the equalization built in, and some setups need a separate standalone phono preamp box between the turntable and the rest of the system.

Before setting up a turntable, check exactly where phono preamplification is happening in your chain, since running a phono level signal into a line level input produces very quiet, thin, harsh sound, while running an already preamplified line level signal into another phono stage causes distortion. A common mistake is buying a standalone phono preamp when the turntable or receiver already has one built in, or the reverse, plugging a turntable with no built-in preamp straight into a regular line input and wondering why it sounds wrong.