@t_ramey Sorry, I totally missed your posted question to me a couple weeks back.
I’m 98% sure that’s what I’m running, but my lettering is quite worn and is in white paint "845" with "made in China" below it--all white paint, with no printed brand, and nothing in red paint. However, from the photos, the physical design appears to be identical in all the parts I can see clearly. I will admit I can’t remember where I got them--I think they came with my used purchase of the Thoress 845s, which I think are somewhere in the 8-10 year old range. Maybe my "As" are that old too?
As to the A vs. B answer, I fear today’s answer is going to be longer and less useful than you wanted, as I’m a little compromised right now in between a (long) move to a new house, and my Thoress amps and spare B tubes are already moved to the new house. Therefore I can’t easily recreate my A vs. B this morning in the Melody. I may go to the new house this weekend and I can try to remember to look for the Bs to bring back.
From memory, I felt that the As were a little more "spirited" in the Melody ("live"), yet without the slight harshness I thought that I remember reading folks often found in the As over the Bs, and that I think I found to be true in the Thoress 845s. I’m pretty sure I had heard an increased "ease" with the Bs over the As in the Thoress amps, but still a very "live" sound--I know I fairly clearly preferred the Bs there, but I don’t know it was night and day. "Ease" might not be a great usage here--maybe I’m thinking less harshness (which wasn’t great to begin with) and a little more soundstage depth in that statement. The Elrogs were a clear step up from both...in the Thoress amps, not in the Melody.
To further confuse matters and make my response perhaps even less useful, I never had the Thoress amps driving my Altec Lansing Valencia 16-ohms, which is what I have the Melody amp driving. It’s possible with that Thoress 845/Valencia combo, perhaps I would have preferred the A over the B there too? I won’t be able to do that test for several months.
