I love 6550 tubes and I'm looking for the best amplifier that uses or can use these tubes. I had a Koch Multitone which was a great amp but I was never really crazy about the overall equalization. Ideally I'd like to have something like a Bogner Shiva with 6550s. I would prefer a 3 channel amp with lots of gain. The clean channel doesn't have to be perfectly clean (never had much use for 100% clean). So, any suggestions?