For a long while there was a trend towards battery powered source gear. Advantages were many: lower noise, no cords to deal with, better isolation. But in general they did not succeed because they sounded worse. Why? Because of what made them special, the batteries themselves.
We know from years of experience that the lower the power supply impedance the better the sound quality. It's a demonstrable fact and one that we spend a good deal of money on in all our products: bigger transformer, more power supply capacitors etc. Batteries - at least the ones in typical use on battery powered equipment - have much poorer regulation and therefore higher source impedance.
A battery doesn't have to have this problem but to overcome it you need a relatively large battery. So, the fact that many a battery powered unit sounds wimpy isn't an accident.
I wish I had more time to investigate all this as much of it doesn't make sense. For example, why would a class A amplification stage care about power supply source impedance when it has a constant current draw? Good question and if only we had more time to answer it.
For now it's good enough that we know what works and address it as such.
But still - a battery powered unit is ultra cool. Love the no wires.
