I am not familiar with the NAD amp you have, but that might be an area for improvement. It's a tough move considering that you have three that match and that is good for home theater performance. Did you try a Rotel amp since you have a Rotel pre? A better quetion to post might be "Best amp for Meadowlark Speakers". What kind of improvements are you looking for? Dynamics? Soundstage? Warm? Tubey... Also, what kind of music do you prefer would help out.
Stewart
