For now I have the 500a driving a pair of Philharmonic Audio Affordable Accuracy Monitors. They are full range bookshelf speakers. I recently acquired a pair of Infinity IL40s from the Interlude series. I suppose they qualify as vintage - they are old enough to vote! They are probably 17-18yo. I'm surprised at how much bass I get from the 500a. When I had them driving the Salk Song Towers a week ago I was amazed at how well they sounded with only 20wpc to drive them.