GPSS-650: Does it work differently on battery vs. wall power?
No. The GPSS-650 works the same whether it's running on its internal battery or plugged into a wall outlet, and you won't hear any difference in sound between the two.
When you plug the GPSS-650 into the wall, the battery charges no matter what position the power switch is in. If you want the fastest charge, set the switch to the CHARGE position.