Kharma Exquisite Reference - low power, low volume

Has anyone had experience driving these speakers with low power tube amps? What minimum power is necessary? Also, do these speakers play well at low volume?
Very nice speaker. Many people have run them with low powered SET amplifiers, but I prefer more power on them. Room size and listening preferences determine just how much power you will want.

And, no the need to be turned up or the sound is very closed down and lacking detail.