@thiefoflight Yes, I've tried rolling tubes in the Luxman after reading several pro reviewers report great results. I started with the rectifier and am using a 1960 Mullard with nice improvement, particularly to bottom end grip and bass heft. I then tried a quad of used Tele ECC83's and they completely degraded the sound so I went back to the stock JJ's which actually sound excellent. I'm wondering if I just got a bad batch of ECC83's. I rolled the two ECC82's with a pair of mid-50s Tele's for a slight improvement over the stock JJ's so they currently remain in place.
It's interesting with the noise issue on the Herron. I know that Keith was very meticulous selecting the best EH tubes for the unit and I'm now realizing he probably had to because only the quietest tubes would yield an acceptable sound with his circuit design. I don't know why he didn't use the 6922/6DJ8 in his phonostage which is what he uses in his linestage. All this talk of noise wouldn't be an issue because the EH 6922 is one of the quietest tubes there is for this purpose with ample gain.