Khartago monos are a good choice for Maggies. I have the Maggie 3.3R with true ribbon. They present two challenges. First they are very hard to drive as any Maggie owner will tell you. You need a lot of current. Second, they are very sensitive to poor recordings and mastering. If the recording is a little bright or over compressed, the Maggies will sound harsh and thin. Klaus built my Khartago monos specifically to address these two problems. The first problem is completely solved. Plenty of current. No blowing the ribbon (I had done that 3 times previously). Very stable at the low impedance required. The second problem is 80% remedied by the Khartagos. Much more dimension and detail than I've ever heard without the overly brittle experience. I'm doubtful you could find any amp that could make this difference unless you want to spend at least $15K or more. I would certainly recommend a tube pre. I hear Klaus has a nice one. I'm running a Rogue 99 with some vintage tubes.