New tubes...far more power??


I replaced my quad set of KT150's in my tube mono blocks a few days ago...replaced with a new set of KT150's that were quad balanced and now for some reason the power output is considerably more. So much so that i need to drop the volume control on my preamp by three notches! Plus, the sound quality is actually no better than before...and maybe even a little strident! Anyone have any idea as to why this would be? 
128x128daveyf
+1 Yogi...that was my first thought. If the old set was "worn" then the new set would be noticeably more robust in dynamics.
Hard to say. I've replaced a lot of sets of tubes over the years. Gave up on tube rolling after the first few tries proved its just not worth it. So almost always mine are only replaced either after quite some time (years) or they get noisy, or once in a while flare out. The one time I had an experience like yours the tubes had run a very long time, maybe 5 years, and then the new set seemed quite a bit more dynamic and loud. But not strident. Never had that. Not even close. Why we have tubes in the first place, to avoid this. 

Hard to think of any tube that could legitimately be called strident. But that would seem to be our only option. That you got some bad tubes. What did you have, and what did you replace them with? And strident, what exactly do you mean by that? Not quite as sweet as before? Or grating and hard?
Does your amp have auto-bias? If so, you may have to reset and bias to spec for new tubes. The auto-bias then maintains as needed. Check your manual.
@dweller   My amps are auto biasing, but they have no method to manual bias, I don’t know any auto bias amps that do.