When I had the 2Bs, a similar budget design, I used a Hafler DH200. It was a little dry and clinical, maybe, but it seemed to suit their character. I also tried the Dynaco ST70 which didn't have enough bass, but the mids, especially strings were decent.
Positioning is everything with these types of speakers. They need to be loaded off the sidewalls, very close, and have a good 6 to 8 feet behind them. Even an inch or two this way or that can make a huge difference.