@pinwa Sorry for that. My preamp is a Supratek Cortese. Note that I did not say that different tubes don't have a different sound. I think they do. Hence my preference for KenRad VT231s. Or red-base 5682s. I have enough tubes that I've always been on the fence for spending the $$$ on new production tubes. But I'm very curious about how they sound and how they might compare to the vintage tubes.
And it is probably more accurate to say that, in my email exchanges with Mick, the owner and builder of my Supratek, that he places more importance on the circuit, tube reliability, predictability, avoiding microphonic tubes, consistency/close matching between the two sections of the dual triodes and a reliable source of supply than on stating which old production tube is the best. As a builder his needs are different than an owner/user. He needs tubes in *quantity*. I think nowadays he's building with the LinLais.