A linestage is simply, a preamplifier that doesn’t have a phono section.
It takes a lot of circuitry to amplify a phono signal, before it ever gets to your preamplifier.
So if you look inside a preamp that has a phono section, also called a phono preamp, or a phono stage, sometimes the phono section will take up half the interior of the chassis.
If your preamp does not allow for the pre-amplification of phono, it’s a linestage.
