Tubes give a very nice sound to B&W's. However, you cannot drive them well without high wattage amps. You can use as little as 100 w. per channel, i.e. Audio Research VT100, etc. You will, however, not obtain the ultimate in sheer muscle unless you go to more like 200 w. of tube power. The Pass X350 is certainly a good choice as well, and I have heard it on these.
