1960 Brimar 12AU7's in xDuoo TA-20


Dec 28, 2020
Very nice 👍, sound?
Dec 29, 2020
I'm not very good at analysing audio impressions, but these Brimars sound very natural and revealing. The low end is solid without being over emphasized. The midrange sounds quite realistic, and I cannot really give a meaningful impression of the upper end because my hearing rolls off a bit too much there. In general, I get a very realistic and musical presentation with low to moderate volumes. So far I've only been playing digital source, but I will move the unit over to my audio system and listen to some vinyl. With more time I will listen to a broader range of music for a better impression. I'm also swapping in a pair of NOS Sylvania long plate 12AU7's, and in a few days I should have a matched pair of NOS RCA clear tops from that same period. At this point, the only thing I can say with certainty is that the Chinese OEM tubes have a less realistic sound. I wouldn't say they are harsh, but perhaps more sterile and less organic sounding.
Dec 30, 2020
The RCA Clear Top tubes work pretty good in the TA-20, especially if you've got cans that are on the darker side of things; needing less bass and more top end sparkle. I found them to have a bit more treble focus than the current production ElectroHarmonix 12AU7A and Gold Lion B749. Nice sounding, just a touch prone to making my sibilant cans... even more so. YMMV there. I ended up rolling over to current production JJ ECC802s and sticking there, purely because I like the JJ extra long plate sound. More bass and mids. If you haven't gotten a set already, they're pretty worth checking out. Can be had for pretty cheap if you don't care about gold plated pins. You nailed it on the head about the Chinese tubes. I absolutely can't stand them in HiFi. I'm sure they'd be fine if I was rocking them in a guitar amp (and I didn't have any tube specific breakup preference), but in stuff for serious listening they're a bit too airy and uncontrolled for my taste. Plus there is the problem that most of the cheaper amps (sub $2000) out of china come with unmatched and barely tested tubes. They'll generally work, but they got no balance, and may have wildly different levels of amplification from tube to tube unless you're buying from a vendor who cares (matches).