No input transformers?
Chinese valves? Waste of space, a lot of them. At least they can be changed easily enough, though.
I would have thought the distortion ought to be much smoother at 300V than 100V if the valve is a 12AX7 (as I think it is) but I guess you're right that there's a lot more separating this unit from the boutique stuff than just plate voltage. Not all of it easy to put right, either.