The JJ Electronic KT77 is a reproduction of the original tubes that captures the sound that made the KT77 famous. In their typical fashion, JJ has built this tube in a solid construction that is robust and highly reliable. This tube has more headroom than a typical EL34. The low end is fat and defines with detailed and responsive mids and smooth highs. This is an excellent tube for adding more power to the sound of an EL34 amp.