Before answering this question, let’s understand what the Phono input means and what it is meant for. The phono input is available on most amplifiers, some speakers, and quite another sound equipment with input/output options. Simply, Phono input is a jack input port where you are to connect a turntable or a phonograph. It looks the same with RCA ports and is typically seen on old radio sets and audio equipment. The phono input is sometimes indicated as MM or MC, which stands for “Moving Magnet” and “Moving Coil,” respectively. It is meant for recording purposes (Phonograph recordings to be specific). You won’t see this input option (phono input) on many contemporary amplifiers and audio equipment. However, even if you use the Phono input options on your old amplifier, the connection would still work, but you’ll most likely get distorted sound. Also, if you’re going to use this option, then you don’t need the Y adapter cable with RCA plugs, you should search for a compatible phono cable for this connection.