You did not specify price or how large a space you have to power.
If SPL and budget allow, the Lamm ML2 or ML2.1 are tremendous products and possibly a great match with your efficiency level. These are single-ended tube, 18 WPC continuous into 16/8/4 Ohms and pure class A operation.
Both these Lamm models are neutral, musical amps with very low noise and tremendous low level resolution. Something necessary with 93 to 98 DB sensitivity which easily reveal problems in those areas.
If SPL and budget allow, the Lamm ML2 or ML2.1 are tremendous products and possibly a great match with your efficiency level. These are single-ended tube, 18 WPC continuous into 16/8/4 Ohms and pure class A operation.
Both these Lamm models are neutral, musical amps with very low noise and tremendous low level resolution. Something necessary with 93 to 98 DB sensitivity which easily reveal problems in those areas.