Hey everyone. I see that many of you are about get your CTHs. Since I happen to have Serial #00001 I thought I might make a few comments on break in. First, the amp sounds pretty good out of the box, at least to me. But, as we all know tubes take about 50 hours to clear out the impurities still clinging to the various internal parts and SS portions do need some time. I don't think it's necessary to do a marathon break in session for 10,000 hours before listening. My experience has been that after about 25 hours playing music the amp begins to take on its full character. And then after that it evolves into is inherent sound signature. For me, I was able to listen fairly happily even with no hours, noticing the changes at about 25 hours and then better over time. I still have less than 100 hours on the amp. YMMV some. I hope you all like it. It has a long history from a popular and very compact DIY project to a much more sophisticated amp.