I normally put this sort of thing over on the Z Forum but since I have a few friends here I thought I'd post it over here. Just a quick heads up for the folks here on the JJ ECC83S Last week I went through the lastest run from JJ on these tubes and the average gain was down considerably from prior runs. This happens from time to time and is of no concern from a safety standpoint but I would refrain from buying any of these for a while from vendors that do not test them for actual gain. The TC numbers look fine when tested and the plate current looks fine so folks with conventional testers that measure mutual conductance will think everything is fine and dandy ... but ... the plate resistance is very low in this batch and that drops the gain down quite a bit. This happens every now and then to all tube factories and JJ might be the most stable of all the tube factories but it happens to them as well. Typical JJ ECC83 gain runs from 85-100 with a high percentage between 90-95. All the other 12AX7 types run from 75-85 on average. The JJ is the most gainy of any current production tube generally. The current run of JJ showed a spread of <70 to 80 or so, very few over 85. This test was on over 400 tubes. So .... if you were thinking of retubing your amp using these wait a bit until other folks buy what is out there now ... maybe wait a few weeks if your vendor has high turnover. If you buy from a dealer where things can sit on shelves for years just try to assure that what you are buying in more than a month old to be safe.