Old tubes vs New tubes

My Melody I880 integrated has been running the same set of KT88's for several years now. Lately they started going soft, getting noisy, sometimes kind of a white noise, sometimes kind of a pffft sound, different levels, at idle never during play. Okay well they are shot.
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Trigger warning: Tube amp voltage is lethal. Lethal means you could be killed. Seriously. Electricity is really really scary lethal. Heat too. Skin grafts hurt a lot. The following information is of a graphic nature. Do not continue if you are easily disturbed.
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The tubes are really hot from music so I go out and get a cotton towel to change em out. There's an old set I keep around just in case. Lotta hours on these as well but curious to see how they compare I plug em in. Right away, faster than I can change a side anyway, there's this electric zapping sound and I look and see this really cool Tesla coil blue-white mad scientist electrical storm going on inside one of the tubes. Cool as it is I figure this is probably one of those times when less is more. Off goes the amp and off goes me looking for another set.

Ahh, here we go. Brand new (probably) Svetlana KT-88s. Plug em in. Power on. No zapping. No smoke. Okay. Back to Brother's in Arms, Side 3 of the MoFi 45 set.

Right away it seems like nothing has changed, no wait, it is a little more open and extended, little more detailed. The longer I listen though, its like someone's in there turning this great big knob slowly, ever so slowly, up and up and up. And this Gnome, he's got this control panel chock full of knobs- Bass, Midrange, Treble, Imaging, Palpable Presence, Detail, Dynamics, Punch, Slam, on and on, and he starts out scrambling like mad between them but then after a while he gives up and starts straining away slowly turning this one monster knob labeled EVERYTHING!

I love this guy! Within a few minutes its obvious the bass is more extended and a whole lot tighter. The highs are crystal clear, airy and free of mist. The whole presentation is so freakishly dynamic I can hardly believe it. There's a wood block, at least I think its a wood block, but every time he hits it it makes this CRACK! that is so powerfully there you feel it in your chest. I feel it in my skull! Which itself is impressive considering how thick my skull is! There's a bass line that's so articulately and precisely delineated its like you can tell the guy had his manicure at Gene Juarez and not the cheap Korean place. Knopfler is palpably present like never before, he just had a sip of Evian and not the sparking one either and yeah I know BIA is maybe the best MoFi of all time SQ wise but come on! 

Few minutes later I walk out and try and tell the wife about the blue-arcTesla tube. But she cuts me off. "What was that last? It sounded like a concert. It was BETTER than a concert! What did you do?"

People strain to hear differences between tubes. My wife heard this through the listening rooms closed solid core weather-stripped door. Before it sounded like a tube amp. Now it sounds..... amazing.