[Puma Cat]

So, I received some Amperex 7308s last week from Upscale for use in my Val 2. These are reputedly a mil-spec style tube with tighter tolerances and increased durability over the Amperex 6922s that I've been using my Val 2 (which I took out of my CJ Premier 17LS preamp to try over the stock JJ 6N1Ps). I really liked very much what the 6922s did for Val 2, so I ordered these for permanent use in my Val 2 so I could put my Amperexes back in my Pr17 preamp. I somewhat mistakenly ordered Amperex 7308s as I thought that is what I pulled out of my Pr17, as they had an orange PQ label on them, and I have Amperex tube boxes with 7308 on them, so I thought that's what these were.

It was only when I pulled out them out of the headphone amp to put in the new NOS tubes and looked at them closely did I realize the Pr17 Amperexes were 6922s, not 7308s. The confusing about this is that Amperex used orange "PQ" labels for both 6922s AND 7308s, apparently.

I installed the Amperex 7308s in Val 2 last night, and have been comparing them to my Amperex 6922s. These 7308s are white label JAN tubes and are NOS. There are some differences I am hearing, but those differences may be initially due to the 7308s being NOS, and have no burn-in time on them. When I first listened to them last night, they were a bit bright and glare-y, but after about an hour of use, they started to sound much nicer, smoothed out and the high-end glare abated. I swapped the Amperexes 6922s back in before finishing up last night, and at that time, I still preferred them over the 7308s, but I've done another swap of the 7308s back in tonight, and they are coming in to their own quite nicely.

Initial impressions are just that, but here's where I am presently for reference: The 7308s appear to be a bit more neutral, perhaps a bit more resolving, but not quite as "palpable" , full-bodied and textured as the 6922s; the highs on the 6922s might be slightly more laid back than the 7308s, but I'm not going to make any final judgements until I get more hours on the 7308s, they've improved quite a bit just over the course of a few hours last night and tonight.

I've experienced rather significant changes in tubes as they burn in; I bought a pair of Ediswan 6922s for use in my CJ LP70S power amp, and initially did not like them at all, but eventually decided to leave them in and get some good hours on them, and ended up preferring them over the Electro-Harmonic tubes the amp originally came with. Ediswans are a lovely 6922, BTW, so those of you interested in considering these, I would give them a go. They are on the pricey side at $95/ea but one of the nicest 6922s I've heard.

More updates in time, but thought I would give this initial set of impressions, as I had a query via PM about the differences between the Amperex 6922s vs the 7308s.