RCA Bidness

[camsna]

You guys know WAY too much about tubes. I mean - don't get me wrong - I kind of know what's what. But I need a few things set straight.

So. Seems I'm chasing that tube dragon . Well. Not really. But I like to have lots of choices for experimentation and extras in my amps and would love to be able to help friends out and so on. So I'm slowly amassing a small (very small) preamp tube collection. So! Here's what I need.

With all this RCA talk - which RCAs are you all talking about? Black plate? Long plate? Short plate? What the heck? I've ordered a couple pairs. One of the short-plate halo getter 12AX7A variety. And another that look to be RCA rebranded Mullards. Sweet! Never tried NOS Mullards before!

Anyhow. Which version of the RCAs is all the excitement about?

 

[MusicManJP6]

I concur. :wink:

 

[camsna]

Wow! Exactly what I was hoping for!

Thanks so much!!!!!

 

[Timbre Wolf]

And now for another perspective...

RCA 12AX7A short gray-plate – Heavy lows, somewhat scooped mids, bright highs that can become indistinct. Lacks clarity of its older RCA siblings (also, high end not as clear as Tungsram, Telefunken, Raytheon). Fundamental frequencies are more true than Philips-made short gray-plate 12AX7 (such as Mullard, Siemens, Amperex/Miniwatt), which have more harmonic content (a kind of distortion). I agree with Shredd, that this is the most commonly referenced "RCA 12AX7"

RCA short gray-plate 7025 – Steely clean, with clear upper mids and sweet highs. Doesn’t break up like black-plates, but is more fresh and dynamic than other (RCA) short gray-plates. My experience of this one differs greatly from Shredd's, but there may be enough variety in this noise-selected type to justify the paradox of two opposite experiences.

RCA ‘50s long gray-plate/square-getter 12AX7– Solid lows (but not as fat as RCA 12AX7A), mids well-defined, but not as open, bright and lively as Raytheon black-plate 12AX7A. Like a cross between RCA long black-plate and short gray-plate 7025: breaks up a little earlier than 7025; is brighter and cleaner (i.e. later breakup) than long black-plate, but slightly less articulate

RCA '50s long black-plate 12AX7 – Great articulation and early breakup, like the Raytheon black-plate 12AX7A, but fatter and meatier, with a “less colorful” and “dry” feel to it (Raytheon is more articulate, brighter, twangier, juicier and more colorful). Really rips!

I'm glad this question came up. It at least is helpful to know exactly which of the many versions of a tube is being discussed.

- Thom

 

[trem]

You gotta admit that it's also purdy lookin'.