Constant noisy tubes maybe go solid state?

facten1

... as long you buy from a reputable dealer and he insures that the tube tests unused and measures within industry guidelines it is NOS ...

NOS = New Old Stock
Used ≠ New

@cleeds I agree with this 100%.
Interestingly, in the tube re-seller world, there seems to be a propensity to label tubes as NOS. These very tubes are in fact used and measure as if new. I guess if one questions how many tubes from the 1950’s -1970’s have survived brand new in a box (that have NEVER been inserted into a tube socket), the answer to what is going on becomes more clear. Not saying i totally agree with the practice, but how many times has one bought a NOS tube and looked at the pins to see that they are brand new....I know I have bought these from so-called ’reputable’ tube re-sellers and the tube pins are anything but brand new! I was disclosed that they come in an original box ( mostly) and they test as new. ( which is also a ’relative’ term).

And next, when we use the term quiet or noisy are we talking solely about the hiss in the speaker drivers ?

A noisy tube will be just that. It will raise the noise floor through your system. IOW, where your system once had a black background, there is now a layer of noise. In a worst case scenario you will hear some tube rush through the speakers.
Amps, preamps, phonostages with high gain will make the noise from a tube more audible. A phonostage with it’s high amount of gain should always use tubes that have been noise-tested.

Even true NOS tubes in original boxes can have a degree of noise.

True NOS has little to do with test results. True NOS is a tube which has never been in a circuit other than a tester, which can be hard to discern at times. Most true NOS come with original boxes. Being NOS doesnt make the tube better it just means that the tube has never been used. Tests NOS is not true NOS. "NOS in white boxes" is rare and it is a misleading and some would say dishonest claim.

Further, I have seen up to a 20 to 25% variation in the test levels of true NOS tubes from the same family and manufacturer. Add to this the fact that each tester is idiosyncratic by tube type and you quickly understand that the average NOS reading listed of a particular tube is kind of a fiction. 

You hit the nail on the head. You have way too much gain for the amplifier. Check with Mike at quicksilver