Originally Posted by mordy
I've been waiting for this post, and I am looking forward to see what you will find. I have my eyes on a cheap deal of RCA/Sylvania 6J4 tubes. Should I hold off and wait to find out if the diode/triode tubes are better sounding? Half of 12AX7/12AT7 sounds enticing.
Truth is, I thoroughly enjoy almost all of the new tubes I've tried, such as the 4825/6AU6 and the 6AH6. But if good is good, better is better......
I also notice that the new tube categories you list above come in European designations, so in addition to the standard Sylvania, RCA, Tung Sol and GE variants, it seems that you can get Phillips, Mullard and Siemens tubes as well etc. .
If you really want to get into the 6AV6 tube rolling mode, there is a T shirt available LOL.
I'd love to tell you to wait for the 6J4 because they're great or something, but as haven't even gotten my Sylvania 8532W yet, I can't. I keep bringing up new tube types that I'm not even the first person to test; I've basically fallen behind in my own game lol...
Which reminds me I finally got my replacement TS 6485 (1971-72, O-getter, last version), and these are still some great awesome tubes. I realize that even more now after spending a full week with my French 6J4S in the meantime. Those 6485 are a grade in themselves, and anyone ought to try a pair; they are my current best tubes by a fair margin.
Now, a few pictures, as I just realized I hadn't actually taken pictures of the last three tubes I tested. No pics of the boxes this time, as I just didn't feel it added much information, and I preferred to focus on close-ups of the tubes for once (pics are full high resolution if you click on them). I do hate how doing macro at silly small apertures reveals how dirty you camera's sensor is; you never see those dust specks at normal apertures...
First, a bit of tube porn. I think I'd mentioned how I broke a 6J4S tube by bending its pins, and that the glass broke off so neatly, I thought I should take a picture of it, well here it is. See how the grid (the only grid, it's a triode) goes further than the anode width.
The 6J4 (all the ones I've seen have this exact same construction, save for minor mica changes) has a pretty peculiar build with weird shaped anodes held by a U bent sheet of metal; fascinating to look at outside of the glass.
The unbroken, yet mutilated Thomson-CSF 6J4S. See how a little bit of glass got chipped off when I bent the pins.
My West German mil-spec Valvo (Mullard Blackburn) EF94, very well built tubes I have to say, nice and heavy feel. Good luck finding those!
And my current favs, the Tung Sol 6485. This is the first pair I got, and the left tube is now dead (new pair is on the amp). Notice how the left tube has some degree of black grainy screening and the other one has none. It's weird, as these two tubes have the exact same code on them, and the same export dates (Germany) on the boxes. It's even more evident on my replacement pair, where one tube is almost all black, and the other one is perfectly transparent.