Desalvo55, the tube sockets in that amp overheat as they were never intended to handle the filament currents that a 6C33 requires. So the filament connections tend to develop bad connections after a while. If the socket is not too far gone the filament connections (the 4 opposite the large pin) can be retightened and you will be good to go for a while.
Eventually though the socket will fail and should be replaced. This will be evident as tightening the filament pins will not seem to last so long before the tube won't light up properly again.
The Russians spec'ed the socket to be replaced every time the tube is replaced, as they primarily used the tube for military purposes. So when that tube first made it into this country (BTW we were the first US manufacturer to use them in a product) the socket was shipped with the tube.
In consumer gear though there is an expectation that the socket will last longer than that and they do. But you should be aware that they do have a service life that is measured in 1000s of hours rather than in years or decades like most tube sockets. Realistically I think you can get about 10,000 hours out of them- that will vary depending on how hot the amp is actually getting.
(FWIW it was this tube socket thing that convinced us to stay with the tubes that we use in our OTLs.)
Eventually though the socket will fail and should be replaced. This will be evident as tightening the filament pins will not seem to last so long before the tube won't light up properly again.
The Russians spec'ed the socket to be replaced every time the tube is replaced, as they primarily used the tube for military purposes. So when that tube first made it into this country (BTW we were the first US manufacturer to use them in a product) the socket was shipped with the tube.
In consumer gear though there is an expectation that the socket will last longer than that and they do. But you should be aware that they do have a service life that is measured in 1000s of hours rather than in years or decades like most tube sockets. Realistically I think you can get about 10,000 hours out of them- that will vary depending on how hot the amp is actually getting.
(FWIW it was this tube socket thing that convinced us to stay with the tubes that we use in our OTLs.)