How does the sound of a power tube change, over time?


I have a pair of Rogue M-180 monoblocks that each use a quad of KT-120 power tubes.  I'm considering a new set of power tubes (same brand, Tung-Sol)  

I realize this question will depend on the specific tube type and amp, but I'm curious about the common experiences.  For those of you experienced owning the same tube amp over years and replacing the power tubes with the same brand of power tube, what did you gain, sonically?  E.g. as power tubes age does the amp suffer in terms of frequency extension, dynamics, volume, etc? 
c_s

Showing 1 response by lowrider57

as power tubes age does the amp suffer in terms of frequency extension, dynamics, volume, etc?
Yes, what I notice is a loss of top-end extension and a dullness to the sound, as in a loss of dynamics.
But this change due to aging tubes happens gradually, so it’s not something you notice immediately.

That's why I've been looking for an affordable tube tester.