A phono preamp is used if you do not have a phono input on your receiver or integrated amplifier. Vintage receivers with a phono input had a built-in preamp. Most of today's newer receivers do not have a phono input. They have a video, AUX, TAPE, or other non-phono input. If you plug your turntable into one of these inputs, the volume will be extremely low. Thus, the phono preamp. You put the preamp in between the turntable/phono and the receiver and it boosts the output signal of the turntable. This will get you listening to your albums like they were meant to be listened to. This inexpensive preamp features one set of inputs and outputs.