Hi I have just bought a Boss AB-2 to switch between 2 amps. I have connected my guitar to the IN/OUT input, my Vox ac30 to the a input and my Marshall 1959 SLP to the B input. The problem is that when i select the A input I heard only the vox but when i select the B input I heard the Marshall and a bit the Vox. Why I don't only heard the Marshall when the B input is selected??

Best Regards