We built a pair of these many years ago when they first were produced by Dyna and we were Dyna dealers.
We were underwhelmed by their audio performance. Sound kinda like big flabby guitar amplifiers.
Close examination told us not enough bandwidth in output transformers, unobtainium output tubes which needed to be replaced in matched quad sets, amp used series/parallel sets of 4 x 400V power supply caps to get 600V working power supply voltage as 600V rated ones not available.
We built the pair, measured and listened to them, sold them, and never built or recommended them again. A real mistake for Dynaco in our opinion.
Frank