Pianet Duo - Why it needs a battery/power supply?

[nonplus]

Hi, I've tested a Pianet Duo today, and asked myself why it needs a battery?
Couldn't find information about this.

I'm not really sure I've got a little electrical shock when closing the lid (aluminum cover) while the Pianet was turned on. Is this possible?
I mean it's only 9V isn't it? Is it save to touch?

Thanks

[OZDOC]

The Pianet built into the Clavinet/Pianet Duo is the version that uses electro-magnetic pickups.
The electronic requirements of both the Clavinet and Pianet only relate to a pre-amplifier to prepare the signal for output to an amplifier.
This is a low-voltage, low current requirement, more than adequately powered from a small battery.
There is no electrical danger involved in this circuit.

If you were powering the unit from a mains voltage adapter that managed to fail in a way that sent mains voltage to the keyboard's 9V input this could conceivably create a hazard.
But this would be a very unusual occurrence.

Perhaps shoes or clothing you were wearing built up a static electricity charge that discharged when you touch the Duo's metal components?

David