That's right! And having a pair of B65, I was looking for something that would sound similar without me having a minor heart attack every time I pulled the tubes out of a box and put them into a tube socket. Then I discovered the GEC/Marconi 6J5/L63 and various reports on the Internet that said how good 6J5/L63 were in general. Then came the adapters for the WA22 I had at the time, and then came an amp (or two...) that didn't need adapters for 6J5.
The 'Philips 6J5GT/G arrived prematurely and has an assymetric 'sheet metal' bottom getter. Don't know how to describe the shape. Six-sided, with a little bulb in the middle.Does anybody recognize this tube, branded Philips. Who might have made it?
I have just bought it, out of curiosity, but it isn't delivered yet. Also bought another, supposed to have been manufactured by National Union.
Photos from the auction.
Congrats!!!!
I finally broke down and picked up a pair of Marconi L63 grey glass. It has been a while since I have listened to my well used B65 but my gut feeling is that tonally the two are close to identical. The usual 6J5 advantages, such as improved separation and imaging, apply of course. I fully expect the prices on these to keep quickly climbing skyward as more and more people realize they can get the B65 sound through adapter usage.
To my ears they sound substantially different from the GEC L63 straight glass too. The presentation is quite a bit different IMO. The GEC presents with a much denser stage and dare I say is superior at pulling out low level texture detail. The Marconi grey glass is quite a bit more open and airy. Hard to really call one better than the other..... I think a better way to think of it would be in terms of what headphones you are matching them to. Paired with something that is already very open sounding like an HD800 I could see the Marconi leaning to the thin side, so the GEC would probably provide a nice counterbalance there for example.
The coke bottle Raytheons, especially the round plate version, are actually fairly close to the Marconi tonal presentation too. Not super close, but there is definitely a resemblance compared to some of the others that are clearly different flavors. Mostly the Marconi is just one step higher in overall refinement and finesse, but you certainly pay a premium for what is ultimately a fairly subtle improvement.
I'm glad I stopped hunting for a pristine pair that I would then not want to actually use in an amp. The ones I have test well but kind of look like mutts so I will have no qualms actually running them when I feel like it.
Just got a pair of Brimar branded 6J5GT tubes (no visible codes). Based on how they look and internal construction they are Ken-Rad VT-94 tubes from the mid 40s.
After playing for a couple of hours one tube started to develop a greyish shadow on top - I assume that it will turn into a black spot later.
I have been told this is called anode boiloff and is not detrimental to the lifespan of the tube. (If the tube has a cleartop it indicates that it is not new = NOS; with a getter flash on top I don't think that you can see it).
Why does this happen?
I second the sound.. I quickly sold the couple pairs of Ken-Rad 6J5GTs after listening. They were some of the first 6J5s that I purchased. I believe I had shiny black and gray plate versions. However, some may vary in construction/sound. I just didn’t like mine much.
The 6J5GT tubes I have are from the early or mid 40s. The bases were shiny but corrode easily; the plates are black and ladder style. With a sixpack of Melz 6N12S they sound excellent in my GOTL. (As always synergy is paramount as well as the amp you are using.)
My fav tube combo on the Airmid was a pair of GEC L63 and a pair of 5998s. There seems to be a few variations of the GEC l63, but these are the ones I have.
