Crickets.
Sorry, but I have some NOS RCA grey glass that cost me $50/tube that are vastly superior to my old style Sophia based on the Full Music tube. I actually preferred a new production Tung-Sol to that Sophia in one application. I'm not spending $200/ tube for Sophia's latest offering until a credible reviewer advocates giving these a try. On the other hand, I've had good luck with some of the Psvane tubes. I might give them a try, but I use multiple 6SN7 and I am not sure I could get more than one to fit. Again, the NOS stuff is so good, there is not much of a driver (no pun intended) for an expensive experiment.
Sorry, but I have some NOS RCA grey glass that cost me $50/tube that are vastly superior to my old style Sophia based on the Full Music tube. I actually preferred a new production Tung-Sol to that Sophia in one application. I'm not spending $200/ tube for Sophia's latest offering until a credible reviewer advocates giving these a try. On the other hand, I've had good luck with some of the Psvane tubes. I might give them a try, but I use multiple 6SN7 and I am not sure I could get more than one to fit. Again, the NOS stuff is so good, there is not much of a driver (no pun intended) for an expensive experiment.