A turntable cartridge puts out a few thousandths of a volt. A CD player or streamer puts out about a volt. Your amplifier's normal inputs are built for the second kind. On top of that, records are cut with the bass reduced and the treble boosted, and that has to be undone on playback. A phono stage handles both jobs; we explain it properly in What is a phono stage?

Close-up of a turntable with its cartridge and diamond stylus visible on the tonearm.
The cartridge and its diamond tip at the end of the tonearm: the part generating that tiny signal. Photo: Jacques, CC BY 2.0, via Wikimedia Commons.

Working out which case you're in

  • The amp has a PHONO input. Plug in there, and connect the turntable's thin ground wire to the amp's GND terminal if it has one.
  • The turntable has a phono stage built in. Look for a PHONO/LINE switch on the back, set it to LINE, and use any normal input.
  • Neither. Buy a phono stage: turntable into the phono stage, phono stage into any line input.

The mistake everyone makes

Plugging into a normal input anyway. It plays, quietly, with almost no bass and a lot of noise once you turn the volume up. That's the missing phono stage, and the fix costs nothing.

One piece of jargon may cross your path: MM and MC, moving magnet and moving coil. Almost everything a beginner owns is MM, and almost every built-in phono stage is MM-only. MC only matters once you've deliberately bought into it, and you'd know.