Jfacker, the KT90s sound just like the two things you heard. More power, bass, neutrality, and "solid stateness" as compared with the KT88 tubes.
Bartokfan, one thing to keep in mind is that comparisons should be made using equal numbers of tubes. If that is the case, the KT90s will do all of those things. But, since you are moving from a JOR to a DA60, you are doubling tube count, and really upping the size and quality of the transformers and capacitors. You will also now have an active preamplifier section. The DA60 bass will be superior without question. If you switched to 8 KT90s in the DA60, the comparison will once again hold true. For the record, while I have both tubes, I prefer the KT88 - it's a beautiful sounding tube.
Bartokfan, one thing to keep in mind is that comparisons should be made using equal numbers of tubes. If that is the case, the KT90s will do all of those things. But, since you are moving from a JOR to a DA60, you are doubling tube count, and really upping the size and quality of the transformers and capacitors. You will also now have an active preamplifier section. The DA60 bass will be superior without question. If you switched to 8 KT90s in the DA60, the comparison will once again hold true. For the record, while I have both tubes, I prefer the KT88 - it's a beautiful sounding tube.