Apparently, the looks of the series turned a few customers away... way too serious looking, especially considering the period during which these were introduced.
But once you let any of these warm up - bang !... you'd almost wonder what hifi did do for the past thirty years to bring you a better music reproduction ; hook it to a decent LP turntable and you really start wondering.
The original PMA-850 doesn't have a rec-out selector or Class A mode ; the PMA-830 no high filter but regains the Class A possibility.
The ultimate PMA-850II has it all (but the muting switch which is replaced by the Class A / B function), has better specs and is, previsibly, the rare beast.
All are very healthy units and built to make music for a nice set of decades - pretty rare nowadays !
A real PMA-850II here.