Power an amp and component with batteries instead of direct outlet power?

"It is common for guitarists and bassists to use batteries in their effect pedals because the pedals sound quieter and easier on the ear."

That's not true. Batteries are used in guitar effect pedals because they don't require a lot of power and make a big mess with cables. As the effects products get bigger and more professional, they don't use batteries.

Vinnie Rossi at Red Wine Audio / LIO and Veloce also focus on high end gear using battery power. Cheers,
Spencer

It is rumored that Eric Johnson can hear differences between brands of batteries in his effects pedals. Now THAT'S bat hearing!

I prefer to not change the batteries in my "stomp box" pedal board heap and have found serious low noise power supplies work fine. I have an old ac cabled MXR gizmo from the early 70s (I no longer use) that powered up to four devices using phone plug inputs. You bought these replacement back plates and put 'em on your MXR boxes and ran the phono plug cables to the power thing...there ya go. Used that thing for manny years. I've heard Johnson's claims and it fits his personality.

It's not a question if it works but if it will sell. That is always the answer to "Why not do..."