How about considering using 5751's instead of 12AX7's? Apparently most of them are better. I think some of the best could be Sylvania Black plates..For more info on this, check out Joe's Tube Lore; he provides a very detailed account of his listening experiences with 5751's, 12AU7's and 6922's.
Also, just by the way, regarding Chinese Shuguang tubes, I have purchased a quad of Shuguang EL34's for my C-J MV55 amp, amd found them to be immensely superior to the Electro-Harmonix of the same type I had in there. With EH 6CA7's, however, it's a completely different story.
Also, just by the way, regarding Chinese Shuguang tubes, I have purchased a quad of Shuguang EL34's for my C-J MV55 amp, amd found them to be immensely superior to the Electro-Harmonix of the same type I had in there. With EH 6CA7's, however, it's a completely different story.