Well, just a brief story, maybe this will help you. In the '90s I was a Proac owner, first the Response 2, then the Response 3. Both very tube friendly, very easy to drive with the ARC tube amps I loved (D76A, then the VS55). So when the 3.8 came out, I figured, hey, why not. But I should have done my homework because the 3.8 was a different animal. The VS55 didn't control the bass very well and I suspect the 3.8 did not have a tube-friendly impedence. I later found out that they did much better with higher powered, higher current, 4-ohm friendly solid state, so the the 3.8s had to go.