Heeeelp New used BAT Vxi3 - Hisssssssss

Oops Vk-3ix - my mistake there

So I switched out the stock tubes and dropped in the Mullards that came separately with the unit and the hiss stopped.

But now some wierd things are happening the new tubes (I say new they have 50 hours on the according to the previous owner):

1. I hear this ding - ding - ding when the preamp is just started lasts about 3 min. Its supper faint but its coming through the speakers. It almost sounds like very soft bells.

2. The bells go away then i start hearing a crackling noise from both speakers that's faint and doesnt go up with volume. Once a few minutes go by it only come out the left speake and the right speaker seems normal. I switched the tubes and the crackling switched sides.

3. There is a louder hiss from the left speaker than the right, though not nearly as loud as the stock hiss and it can't be heard from sitting position.

Could tubes go bad thru the shipping process?

Im a little confused. Which part is normal, the ringing at startup or the crackling. Because the crackling can be easily heard in soft passages even after a half hour of play. That can't be normal can it.

The previous owner did send me a receipt which showed the testing data and where he got them from. But since I purchased used from him I'm not sure what I should do about contacting the seller of the tubes.