You don't mention your budget but here's a couple of suggestions: I have the Beethovens but will be selling them soon as I move up the food chain, so these are from personal experience. At the rather expensive range, a MAC MC2102 was the best followed by a Sonic Frontiers Power 2. Down the line, I had a Classe CA200 that was also great with the Beethovens and lastly both a proceed AMP2 and believe it or not an Outlaw 750 also worked well. I guess the moral is, the Beethovens work well with most amps but I would look for an amp that's fairly powerful.
Good Luck, Mike.
Good Luck, Mike.