What did you experience when tube rolling in a Carver Crimson 275?

@oldhvymec,  yes indeed I wouldn't just pop in something that doesn't fit the specs and tube pinouts.  Further, KT150s may not be recommended.  I heard some say Frank Malitz told them they could be used with the caveat that the amp was voiced to the KT120s.   

@motoraway,  Thank you for that information.  I'll try some KT77s/KT88s next.  

I'm particularly curious to hear if people think swapping the 12 volt tubes have less significance in this amp as opposed to other amps. 

Status Update--

I have rolled quite a few signal/input tubes.  So I finally got around to putting in different power tubes. 

I am running Tung Sol 7581A (reissues, of course).  I think this tube is basically an upgraded 6L6GC tube.  It does have some (slightly) more headroom as its plate dissipation is rated up to 35W.

I had to let them warm up for 10 minutes before they would bias properly.  They did and stayed there perfectly--haven't moved. 

The midrange is more forward and pronounced with a touch more sweetness than the KT120s.  Bass is tighter and more defined, but it's not as prominent.  

Highs have similar air as the 120s, yet the sound a touch crisper/shinier--not brighter though.  

Very fun endeavor.