I used an ASL AQ1003DT, a 30wpc integrated tube amp like the CJ, with a pair of original Concertos and it sounded great. I believe the CJ is 50wpc so it should drive them even better. My room is 12x18 but one of the sides is completely open to the rest of the house which is 50 feet long. The amp drove them with ease. I never had to turn the volume knob near half way to get them to sing as loud as I can possibly want. The Concetos are not too demanding when it comes to power. However, give it some quality current and they will reward you. Good luck.
