What I most like about the sound of this amp and my single ended amp that uses this tube (a *em7 tube is how the input and output are not using two diverse types of tubes, but are in the same envelope. Tube get hot and heat is a vibration. Thus with one tube functioning as input and output, there's a sense of coherence. The tube itself seems almost as quick as an el84, having had a Decware and a Music Reference 10 (both using this tube at the same time as my *em7 SET, but also has more lower midrange weight which is typical of wider bodied tube.