Thanks holmz. Appreciate it.
Steakster I've rolled rectifier and output tubes and have two sets of od3 voltage regulator tubes one being Raytheon and the other General Electric. I notice a slight difference between the two I was more wondering if Telefunken or other premium vintage manufacturers like Amperex made them and if that premium brand is far better than what I have. But like you said they are not expensive to start toying around with some which I will probably do.