Adcom GFA-565 Capacitor Replacement

I own two Adcom GFA-565 mono amps. One began to thump while in use, so I brought both to an authorized service center. Tech tells me that he is finding DC across speaker leads on both amps, and that oversize capacitors need replacing and that he thinks Adcom no longer makes them. I asked for alternatives, he said "they make great anchors". Is there a place I can obtain original or acceptable substitutes for the capacitors? THANKS!