Have you tried the KT 88 tubes, I have the Focal 1038 be with Primaluna HP in mono configuration. I tried the KT 150 and always felt I was not getting the best out of my system. The EL34 are better but the KT 88 gets everything right from top to bottom a lot of detail and some nice tube warmth . I have a set of Gold Lion KT 88 and mullard Kt88 they both sound the same. And they are made in the same factory the even look the same but have a big price difference if you get the mullards you will not be missing anything.