Attention! Before buying any 5AR4, 5U4, GZ33, or GZ37, here is a hot ticket from Uncle Kevvy: Buy the Philips 5R4GYS made in Holland. Click here for info. 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 are no surprises.
On to the Russian 5U4G. Made in Russia. My sources tell me this tube is no longer in production, which is a shame because it is so well-built and sounds great. Made in the Svetlana Electron Devices factory in St. Petersburg. This was used for ages as the stock rectifier tube for many products including the Cary SLI-80 Signature.
We were able to locate a stash of these, so we have them in stock now, but we had to pay a premium and I didn't get very many... which means they'll probably sell fast. These have the original Russian military stock 5C3S or 5U3C markings on them, but they're all 5U4G tubes.