My first post to this great forum. I could share some impressions about tubes with you fellow Little Dot users.
I currently have following driver tubes: 6K4P -84, 6J3P -84/82, Tungsram 6BE6, GE 6AU6A -70, 6J1P 1991 groove, 6J1P -71, GE JAN 5654 -69, 6J1 -80/77, 6J5P -89.
6K4P are easily my worst tubes. New from the box these sounded horrifying. Bass was so boomy and otherwise sound was a mess. After some burn-in sound has come way better, but i still don't recommend these for any serious listening. Bass stays little muddy and instrument separation is bad. These need about 40% more volume to sound same db level as others.
6J1P -71 are great for everyday listening. Just a little bit smooth russian sound, but clean and good soundstage. Can't say anything bad about these. Far better than those newer grooved models, that sound little cold with some sort of spike in treble and keep humming noise when hand near.
6J5P -89 are my best tubes so far. Can't find any flaws. Very analytic and clear sound with great soundstage. Good separation for instruments. When i heard these first time, they made some wow-effect. Can't say that does burning in have made any difference to sound.
These impressions are with LD MK II and 6N6P-i -86 powertubes. Hope i get ordered 6N6P-IR -83 tubes soon from Russia.
Sorry about my bad english...