Robert Halvari, Creator at Notes on vinyl
Phono vs Line: A phono signal is the tiny signal that comes directly from the turntable cartridge, while a line signal is an amplified version of the phono signal
What Is a Phono Input? The phono input on an amplifier for turntable is for use with a phono signal – i.e. those that tend to be a little weaker.
What Is a Line Input? By contrast, the line signal is far stronger and will likely have been preamplified already or will otherwise be ready to be properly amplified.
Phono vs Line: Is LP and Vinyl the Same? Both the phono input and the line input refer to two separate stages of the amplifier
The former will be of use to those using a (perhaps older) turntable that requires its own external preamp stage to boost the weak audio output.