Bought this tube for my taga tha500 hybrid heaphone tube amp. Definetly miles ahead of the stock 12ax7 chinese tube that came with it. But it is not intended for hifi use, it is meant for guitar amps and that is where it shines. On headphone or speaker tube amp, it gives kind of a overdrive sound to verything once you pass certain volume level. Still good, but not optimal for hifi.