Edited

I am not really sure about 13V - hopefully someone else would know.

As to the volume button, if you're using the bean and the latest cable and the cable is plugged into port I you don't need to worry about the volume.

If you need to turn the volume, I think the picture logo would suggest that if the button is turned to the left most position the volume would be the highest (the volume bar is the highest on the leftmost side).

Thanks for the buski tea recipe! I don't have the synchrometer so yes, would have to buy the organic barley hoping that one would not have any (or minimal) contamination. Not sure about dowsing done after one buys it, but perhaps in the store that should be done, yes.