Sksos1, I admitt, I am afraid to go down what could be an endless Rabit hole of tube rolling!, I love my sound now!, however, I have followed Jafox's post about tubes, so Steve, what do you think about this? I have a 6z4 recetifier tube in the power supply that is vintage American, how or why this came stock in my vincent player is baffled me,it sounds great, the problem with that tube, there is no replacement for tube rolling, so I will have to go back with the same there, but following Jafox's tube exsperience on the threads, I learned from him that a good tube for the 12AU7 tube replacement is or could be the RCA 12BH7 Red Label tubes, or the 12BH7A Black plates tube, and I suppose the Telefunken 12AX7 tube for the 12AX7 tube replacement, unless any one has a better idea for the 12AX7 position?, Steve, I have incredible Bass and treble extention with the stock tubes now, I would be angry if I lost that part of the sound, I have read that some tubes can have you loose bass, My player has only one chinesse tube inside stock, the other tube that came in the player stock is a harmonix tube and then the American 6z4 tube that I do not know who made the tube?, cheers.