New tubes...far more power??

I will try the unplug suggestion, will be using my back-up amp ( a ss design, which does make for a lot less nervosa) for a week or so.
Last night, I was pleased to hear that the tube amp was in fact sounding a lot better, the increase in power was still very evident ( and strange) but the overall SQ was fuller and less bright. I moved a power cord off the preamp and replaced it with another brand...this could have helped.
Here's the interesting thing, my ss amp puts out 250 watts/ch into 8 ohms...and nearly doubles into 4ohms, my tube mono blocks put out 48watts/ch into 8 ohms and not much more into 4ohms...yet the tube amps sound FAR more powerful than the ss amp. ( Yes, the tube amps have massive transformers, while the ss amp has slightly smaller transformers..and the tube amps are mono blocks, while the ss amp is a stereo amp...but the power output in volume is strikingly different...and adverse to what one would expect!) 

What is the brand and model of the tube amp?

Yes! Tubes break-in and age during the first 50 hours of use.

Davey f you must be a tube novice IMO.

@don_c55 you are right, I am a tube novice, having owned tube amps and preamps for more than thirty years.
Plenty of assumptions here. Including that these tubes need to be broken in..
as they were played for about 200 hours when I first acquired the amps (Jadis mono blocks) and were then put aside in favor of the stock KT150’s that came with the amp.

Aside from the possibility that the older tubes were substantially worn out, such that the difference in gain was very significant, it is hard to account for why the new tubes have more gain (not necessarily more power), yet sound so much less desirable.  Is it possible that the tubes are not the same in design or build?  The manufacturer could have changed up something between the two batches of tubes.

In some of the amps I've heard that use the KT150, the sound is a touch too brittle and hard sounding for my taste.  Perhaps, as the tubes age a bit, they soften in sound and you might be someone who prefers that softer sound.