Before buying any 5AR4, 5U4, GZ33, or GZ37, here is a hot ticket from Uncle Kevvy: Buy the Philips 5R4GYS made in Holland. Very rare. We got a stash of them, and they are incredible. The only thing you have to do it make sure that sure you have enough height clearance... we provide you a picture illustrating the height of them so there's no surprises.
Now: on to the PrimaLuna 5AR4 listed here. This tube is made in China and is the best sounding current 5AR4, super dependable, and looks even better. This is the same tube that comes stock in the award-winning PrimaLuna preamplifiers and CD players.
All PrimaLuna tubes are tested and screened to the highest standards.