Gavin,
Don is licensing the production of his Valhalla integrated amp that owners on this forum have praised. I recall that the Valhalla amp is one of several that Clayton Shaw uses to demonstrate the best aspects of his speakers.
I am the least knowledgeable guy on this forum about electronics. I clearly admit it. I remember listening to Roger Modjeski explaining the design of one of his preamps at Burning Amp a few years ago where an attendee asked about worthy driver tubes. RM's minced no words in responding that 6SN7 tubes were a very poor choice of tubes -- "better employed in old TV's", because of their inherent high noise levels. Well, I had had Don's first preamp with 6SN7 tubes (derivative of the Roy Mottram's SP14 design and with Roy's full approval), and his Kootenai amp with the same driver tubes, and wondered how to square away RM's comment with the dead quiet sound from my system. When I shared RM's comment with Don after the show, oh boy, it was an interesting conversation. It is true that few audio designers use this tube in their designs (Modwright and Supratek come to mind), but Don does and is doing so with his new 300b monos and my ears tell me that Don is correct in his use of the octal tubes in all of his designs. Hearing in believing.

