so i have a big problem with the morons that charge stupid money to add a tube buffer to a solid state output stage. modwright instruments, and lampizator for example.
you start with something that has a 200 ohm output impedance, and by the time you are done with the cathode follower, its a 1.5 k output impedance, or in the case of the lampizator something like a 3k or more output impedance. its stupid and counterproductive. but hey there are these glowing things sticking out the top.
you can't make a decent i/v converter with tubes without 6 triodes per channel. and even then, solid state is far better. r2r is a voltage output anyway, not a current output