tube rolling

FWIW, re 6h23's, a tube maven recently told me that the EH6922 and the new production Russian 6h23 sound alike. I have the current EH6922 and have used it in several different applications, amp, pre-amp and CDP. I have compared it with the NOS 6h23's. They do not sound the same at all. I found the old 6h23 to be cleaner, clearer, and perhaps to some more clinical in tone. I found the new EH to be a tad too warmish and unresolving in the bass BUT used in equipment which is not highly resolving or were bass warmth is preferred over clarity they can be very enjoyable. I really enjoyed them with jazz but on SOTA classical recordings the soundstage just got muddied up.

Re JJ's and old Tesla's - The tubes look identical but I find the old Tesla's to be a bit cleaner and more resolved, especially in the upper bass lower mid range. The new ones are IMHO a bit warmer in the upper bass and a bit less extended in the highs, but a nice tube none the less.

I found the EH's to be very quiet, the old 6h23's as well (and very rugged), and the JJ's and Tesla's to be less so.

I have not used the ARC PH, but the JJ's/Tesla's are just not quiet or rugged enuf for my ARC SP10 (I use old 6h23's). I tried EH 6922's in it and was very unempressed with the tone and bass clarity. I thought it was simply an interface problem but I had the same result when I used them in a CDP.

Don't know about the Tungram, I've never used them. FWIW, my favorite 6DJ8 for tone and clarity is the EI or older version "Yugo". If your unit is not too demanding on tube ruggedness these could be wonderful if you can find some. Or if you like a bit more warmth, some Amperex's like BugleBoys.

Hope that helps a bit.

Quietness/ruggedness depends on tube screening/selection. Ruggedness has a lot to do with how long they stay quiet in a given application.

For example, I have an ARC SP10 which is reknown for being 'tough' on tubes. NOS 6h23EB's selected for low noise last, in that pre-amp, thousands of hours. I have tried old and new low noise EI tubes which didn't last 100 hours, nor did old or new Tesla's. Both went from quiet to quite noisy in a short time. The same EI's and Tesla's have remained quiet in amps and other pre-amps, and one CDP that I have used them in. Another CDP I have eats those brands as well as the ARC. Audible Illusions has a similar demand for 'rugged' tubes and many folks use 6h23's there as well.

One of the reasons that ARC used Sovteks so long as OEM tubes in most all of their stuff had much less to do with sonics than just plain ruggedness. My old Sovteks seemed to last forever and sounded very similar to my NOS 6h23's. They were not euphonic but are much better than the later Sovteks and, in my humble opinion, far better than the steel pin EH's which I find unbalanced - too much bass, not enuf mid range etc.

FWIW, I like the old Tesla a lot and presently use them in two different amps. Nice combo of warmth, overall tone, and clarity. I find them a bit warmer than my fav's, the EI 6DJ8, and for a tube a lot warmer look at the Amperex Bugleboy (which my SP10 also eats!). Horses for courses.

Hope that helps a bit.

I've no personal experience them, but I do recall their reputation being discussed in the tubes forum on AudioAsylum. Can't recall if it was good or bad. You might visit the site and do a search under that name (ditto here).