I am using a Pioneer VSX-03TXH receiver and just purchased a set of Martin Logan 60XT speakers. The salesman recommended that I add a Rotel RB1582 200W amp to the front speaker pre-out's on the Pioneer....since the Pioneer does not have a lot of power. Question is...can I add any brand amp like one of the older Carver amps that were close to 1800W? The 200W from the Rotel doesn't seem that powerful. What is the largest Amp power I should use?
Any amp that's designed to handle a 4ohm load is fine. Honestly, you'll most likely find 200 more than enough with those speakers. With a sensitivity of 94dB/2.83v/m you'll be able to play at over 100dB at 4 meters.
Otherwise the speakers are rated to 400watts, so you can go up to around there.