Good morning George and welcome. It would be cool if Barry offered a tuner that we could build ourselves but this circuit merely allows you to use YOUR tuner silently when the mute switch in engaged. If you look at page 4 of the guide you will see that a jack is wired to the tuner pads on the board. That jack would be the connection to your tuner via one of your cables. But because the circuit splits the signal, the portion that goes to the tuner will not continue on to the amp. And the rest of the signal that will continue on to the amp passes through the excellent buffer which makes up the rest of the circuit. So Barry is providing a way to use Your tuner without it affecting the tone you’ve created.