My Edge 10.1 NL stereo amp. I bought it to replace my Pass X-600 monos because of the amount of heat they produced, but I loved the Pass sound. I was really afraid the Edge was going to be a step down due to its lower rated power and the fact that it is a stereo amp as opposed to mono blocks. Not only that but it is not even balanced. Man was I pleasantly surprised. The Edge (IMHO) is more refined, liquid, smooth, and detailed, and has much more tuneful bass. It is a musical joy to listen to.