Paul , nice post, and in agreement. FWIW, I demoed a KT88 40 watt intergrated (chinese model/low end lab) just to see how well the 88's work out on orch. The amp is the same weight as my JOR, but offer more tubes in the pre section. Very disapointing. The 86 db Thor's sucked the amp dry. So as you say, impedance of 86 db is something not suited for some tube amps. With a impedance that low, would you say that a important factor is how well the transformers are made/output power?
Tyler's Lin Sig Sys though rated 4 ohms, has a higher db rating at 92, so my little JOR was able to actually work the large speaker into good performance, if not excellent performance. I was very surprised as the LSS has 2 more drivers per cabinet to push vs my MTM design. I was surprised the JOR came through, due to the greater sensitivity of the LSS at 92. (in spite its 4 ohms).
Thoughts?