1439bhr,
yure correct, only an order-of-magnitude estimate is possible. as i was told by the designer, but he suggested this was a good place to start. however, the cary, rated at 850 ohms output impedence, was at least an order of magnitude better (lower output impedemnce) in my testing, than the rogue.
leafs, while yure correct that i started complaining *immediately*, after using my rogue, i had over 600 hours on it prior to selling, including over 200 hours on nos tubes i bought, to try & *fix* it. the nos tubes helped, but weren't enuff...
regards, doug