Really? I find the amp very fizzy, shrill and it has some really strange stuff going on in the highs. I thought it was due to the low volume, but even when I profiled it with volume at 6 it sounds pretty much identical. Certainly not useable with V30s, which are praised as «the ultimate speaker» for the Jubilee.. It gets worse the higher the gain though, and for some reason it gets much more fizzy at 50 watts compared to the 25w-mode.
But I guess whether an amp is dark or bright is very subjective. It might be dark compared to a JCM800. Slash loves a bright amp so I don't think the Jubilee would be his weapon of choice for so many years if it was very dark That being said, Top Jimi's profiles of his 2555 sounds much better and less shrill than my 2553.