On that note (Tubes108), we had a 6C33C tube that was bad when we purchased the Quickie Triodes. We are the second owners of the amps. Mike Sanders informed me that he now uses bias stabilizers so that the tubes stay more easily within the proper bias range, thus lasting even longer. It takes about 30 seconds to bias all four. When I replaced the tube, I asked Mike if the socket should be replaced as well--I also had heard that some amps require this--and he said, "Well, I sure would expect that the socket would last a lot longer than the tube." As you might guess, I did not replace the socket.
Enjoy!
Howard
Enjoy!
Howard