I purchased an HT3 (with cap upgrade) in 2006. First, there was a hum issue. With Klaus's assistant on the phone, I removed an internal ground wire. Hum issue fixed. A few months in, one of the caps went bad. It was replaced for free under warranty, but I did have to pay to ship this 64lb. beast out to Minnesota. Since then, it has been trouble free, and sounds absolutely fabulous. I leave it powered up all the time unless I am going to be away from home for a while. It runs moderately warm, but AFAIK, that's typical of the 3-channel models.