I agree with Charles, 6 to 8 watts won't do it. A 20 to 25 watt SET might be enough, as benign impedence, can be more important than sensitivity, with tubes. If you go that route, it would be very important to try the amp with the Proacs and in your room, before buying.
I have had a couple of 20watt SETS and can recommend the Ayon Spark, which I use at the moment. Almarro do a nice SET amp, at a lower price, both are excellent. The Viva Solista I used before, is very expensive now and I think the Ayon is as good.
I have had a couple of 20watt SETS and can recommend the Ayon Spark, which I use at the moment. Almarro do a nice SET amp, at a lower price, both are excellent. The Viva Solista I used before, is very expensive now and I think the Ayon is as good.