found tube i like, only small bits of red letter,what tube brands used red lettering?

[ryuji]

Started rolling through my stash of tubes, found a special one for me. Its a 12au7 on the glass etching, and its black plate 3 ribs with only two mica's. the black coating looks almost 'worn' as you can see metal showing through the black coating here and there

im guessing RCA?

even if not, im enjoying my gray plate 5814's. but trying out tubes in my 12at7/ax7/au7 slots i've noticed a trend. triple mica tubes sound better then two mica. black plate tubes sound better then any combination gray. and 5814's sound better then 12au7's. havent listened to enough quite yet but it appears ribs sound better then smooth?

im thinking of buying black plate 5814's so i dont have mixed quality across my five channels.

if you guys are wondering. 12au7 pre-amp 12at7 driver, 12ax7 subwoofer pre

[Wavebourn]

Yes, I saw RCA used red lettering.

[ryuji]

what is everyones thoughts on the trends im seeing? anything else for physical characteristics that other people have noticed shuffling through there boxes of tubes?

another intersting thing i've noticed too... some tubes hum a lot while others are silent but it seems random.


next for me is to start rolling through my stash of ~10 spare 807 pentodes. my expectation is that as the gain is low on power tubes, the brand/characteristics is going to matter less then the pre's
but i got:
westinghouse, many RCA, tung sol, and GE 807 tubes. will be interesting to see, if any differences between the bunch other then 'the strongest testing tube wins'