Originally Posted by rb2013
Well I would take any supposed test readings from a Russian dealer with a grain of salt. Especially at that price. My experience is 30-40% fail testing (below 70% of new), another 50-60% below 90%. And it's usually in just one section (these tubes have 2). Now those will still work but will be a bit weak. The lower output on yours, as you mention they needed additional gain to match the other tubes, is a possible indication of a weak section. This has nothing to do with noise, so tapping won't give away weak output sections. My experience the 6n23p generally has greater output then other 6922s. This is due to they're greater wattage - 300W vs 240W for the 6922.
You could take them to be tested and use the best testing of the 4. Music repair shops generally have testers (most guitar amps use tubes).
Ah, well, that makes sense. If I can find a local shop that can test them, I might do that. I should do an A/B between the two pairs. One pair is marked with dots (like from a Sharpie) on top, the other is not. All four have matching dates, so I could always try mixing and matching. Would be best to get new test results, of course. For $48, I'm not complaining. The extra gain was pretty nominal, and may have been my ears. Gotta love the tree pollen season in VA.
In the meantime, I've got some Siemens to listen to