I found if I use the 10 band eq when running into a tube power amp I can dial in those missing frequencies. I was able to get the axe fx3 to sound to my ears just like my evh 5150iii and orange Rockerverb when going back and forth between them. Hope maybe that helps.Have compared Axe to tube power amp to 4x12 against amp to same 4x12. At least four times, maybe more and with friends/family.
Something is missing as the real amp always wins. Its ok, the Axe and Kemper are more convenient. My tubes can rest and last longer ....