Phono Pre-Amps convert and boost Phono Signal from equipment such as Turntables to a Line Level Signal for use with equipment that does not have one built in. This can include Hi-Fi Amplifiers and AV Receivers, Passive and Active Speakers, Audio interfaces and Mixing consoles.If the below applies to yourself then you will need to add a Phono stage to your system to use your equipment efficiently and correctly:1. Your Turntable does not have one built-in. 2. Your Amplifier or AV Receiver does not have one built-in.3. You are using powered speakers that do not have one built-in.Please consult your user manual for more information on this.You can easily identify if your Amp or AV Receiver already has a Phono stage as there will be an input on the back as shown below-titled Phono.User-added imageFor Amplifiers and AV receivers that already have a Phono Stage built in a separate one may still want to be used. The main reason you may want to do this is for better sound quality. In most cases, you will no longer connectto the Phono input on your amp and this will be done using one of the Line Level inputs, It is best to consult your user manual for further instructions on how to do this.