Would this be the all-in-one solution for someone with HD 650's and Momentums? I have Schiit Modi/Vali stack at the moment, but in the future I might want to upgrade and this package seems to have it all: quality, versability, correct price range, simplicity and looks.
Btw, can you order the WA7 with europlug and appropriate voltage options straight from the manufacturer without hassle?
On your last questions, they don't come with any power cord and USB cable, so you have to purchase them yourself. It is clearly stated in their website.
As for the appropriate voltage, there is a switch at the bottom of the power supply unit that let you select 115 or 230V, so it is very staright forward.
Can't answer you on the pairing with HD650 and Momentum as I never tried the WA7 with the 2 cans