One of my Tubes on the Jolida 301A flickers


I was playing an LP today and noticed that each time a low frequency measure was being played, the sound was distorted. I played the same measure over again several times and confirmed the existence of distortion not previously heard. I watched the tubes while tracking through this measure and noticed that one of them was getting brighter. Thinking that maybe a tube is ready to go, I swapped it out for the adjacent one to determine if this is a tube issue. The same thing happened with the swapped tube. I tried another tube and again the same thing happened.
Has anyone had the same happen to their amp? Can you share what the root cause was?
Thanks in advance.
switchback
Jerrynsr, thanks for the info on the tubes. I'm currently running my source to a CJ pre-amp and I believe (need to check) that I may be bypassing the amp's preamp section. I'm wondering if I should use the tubes you recommended on the CJ unit?
Thanks
Switchback..
Where does the CJ pre-amp connect to ?
I'm real happy with the sound I got out of the preamp tube upgrade. There is a major improvement over the stock Chinese preamp tubes. I didn't even need to burn in the preamp tubes to hear the improvement. The upgrade was definitely worth it for me.
The cj is now connected to a bryston 4b st. My system has never sounded better.
It's true what some say that a high powered byston & maggies are a match made in heaven. These speakers can produce deep and controlled bass.