Hi, Don Sachs here. First, this is not an attempt at advertising in any way. The amp whitestix refers to is now in the second prototype and there is no commercial product.
If you see a 300b that uses a 6SN7 to drive the 300b it will sound ok, but you will never hear what a 300b can do because a 6SN7 tube cannot adequately drive a 300b. Search the web for Lynn Olson's symmetric Reichert. What we have done is to start with that sort of design and then completely update the driver section and the power supplies. The driver is now a triode connected 6V6 for each 300b and it will be coupled with custom wound interstage transformers from Dave G at Cinemag. I tried a version with CCS loading and it was the best amp I had ever heard. I have tweaked that further with choke loading and it is better and the IT version will be the best. There are lots of other tricks in there, and many little secrets, but it is basically 4 single ended 300b amps in one box. Phase split is done up front with a super high quality input transformer. The result is an amp that has all the transparency of the flea watt SETs and the drive of a push pull. It is about 27 watts/ch in this form and sounds like 60 watts/ch. I love the Kootenay amp, but it doesn't sound like this amp..... to my ear it is the best amp I have ever heard.