JM, it's interesting what makes some speakers easy to drive and some not, the Harbeth are a popular speaker amongst those using tube gear and they are only like 84dB. I was at a shop that drove the Harbeth with a Leben tube integrated but when I wanted to hear the Totem with higher efficiency rating the guy switched to a Naim amp saying the Totem needed some current but explained the Harbeth were tube friendly. I've not heard the Studio's with tubes yet but Crutchfield offers a return policy. Granted though they aren't going to play all that loud at 86dB with just a few watts.