I have a pair of 1970's Heresy speakers I got from a friend. When I hooked them up to my very nice Denon AVR I was, like you, surprised because they always sounded better at my friend's house (powered by a Harmon-Kardon Citation amp from the same period). I then hooked the speakers up to my vintage Pioneer SX-737 and there was that wonderful sound again. I then hooked up the speakers to another AVR type receiver and got the same result as with the Denon. Next I tried hooking them up to a vintage Kenwood receiver and they sounded much better. A and A-B type amps just seem to make the Heresy's come alive.
