6SN7 Vacuum tube is an old classic, I installed it in my amplifier that was on for 14 days & the first listening test was very positive, good dynamics, the bass is really present while the midrange delivers a very open and detailed sound. The treble is honest to the music in the finest micro details and the entire sound image is big and wide - nothing has been added and nothing has been subtracted - so, honestly with the music in the foreground. Plays a little better than the tube that was in the amplifier from new. Kind regards Ebbe