Interesting, thanks for sharing. My tube monos weight 55lbs each and have 7 tubes each. My two part tube pre weighs about the same. I live in Central California and will be seriously looking at a class D amp/amps for next summer. My intent is to pair my balanced tube pre ( 8 tubes ) with class D. Thanks for sharing another choice. FWIW , I’m hoping to be in Wheat Ridge in January, maybe I can visit the stereo at Union Station. Cheers , Mike B.