Old 12AX7 Tube ID

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by rockon1, Mar 1, 2006.


  1. rockon1

    rockon1 Member

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    Just got 8 of these off ebay. Supposedly regular grey plate RCA's. just checking with those who know. Got numbers on them . Date Code maybe?
    Etched into glass- ARBC
    Paint- S280C
    64-33
    24B4

    Aby info appreciated. I paid 100$ for 8 of them and I realize I paided too much but damn those auctions!

    [​IMG]
     
  2. Blue Strat

    Blue Strat Member

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    The plates look like RCAs. RCAs have the tube number (12AX7) etched in the glass inside a rectangle (actually, a "flattened" octagon) near the top of the tube. I don't see that in the photos, but maybe the tubes are positioned so this isn't visible.
     
  3. rockon1

    rockon1 Member

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    No 12AX7 that I saw only the letters ARBC is etched in near the top.
     
  4. BozoTone

    BozoTone Member

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    Before ya say they were too much, how do they sound???
    BZT
     
  5. rockon1

    rockon1 Member

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    I thought they sounded better than my favorite JJ combo.Punchier with a meatier, fuller OD sound. Is it a phsycological thing? Dont know but they are staying in for now. Wondering what they are now.
     
  6. rockon1

    rockon1 Member

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    Anybody else have an idea who made em ?
     
  7. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I'm familiar enough with older Raytheon tubes to recognize the "280" as (possibly) their EIA code. If that is true, those would have been made after '62 in Japan, as they have short plates. I've not had any direct experience with MIJ Raytheons, but perhaps someone else can run with this possibility.

    - T
     
  8. rockon1

    rockon1 Member

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    The tubes also say "Made In USA" right on them.Scroll over to the far right tube in pic.
     
  9. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    No doubt. Can't always trust the paint, though.

    - T
     
  10. brad347

    brad347 Member

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    +1. Tubes are notorious for having bogus countries of origin on them.
     
  11. donnyjaguar

    donnyjaguar Member

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    Yeah, that's for sure! I was told this all started back in the 1960's during the cold war where US companies were buying eastern European tubes and re-labelling so customers wouldn't know they were buying communist-made products. It sounds logical to me. I think this practice would be illegal today (and probably was back then too).

    What are people general thoughts on the later Japanese made tubes? My experience hasn't been great but wondering if they are considered to be alright.

    DJ
     
  12. brad347

    brad347 Member

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    I think the japanese made 5AR4s (the ones with the single seam at the top) are great! They're a lot like the mullards (but without the ridges in the plates) and they sound fantastic and are durable, and can be had for cheap. I have three vintage Mullard 5AR4s and one of these and can't tell the difference in any amp I've tried comparing them in. I assume these were made in the 70s or 80s.
     
  13. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    My only experience is with Matsushita (=Panasonic!) EL84. They were my first NOS power tubes, and I thought they were a vast improvement over the Sovteks they replaced. They didn't last as long as other NOS EL84 I have used since (I tend toward Tungsram EL84 as my workhorse brand, with pricier Mullard/Amperex/RCA reserved for special uses), but they were very good while they lasted. I haven't had any Japanese-made preamp tube experience.

    - T
     
  14. rockon1

    rockon1 Member

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    So back to my original question. You guys think these are 40 year old Japanese tubes?
     
  15. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Sorry for the diversion...
    -Short gray-plates are post-early '60s.
    -RCA and GE had similar plates, but you'd likely still see etched print on the glass.
    -Philips family tubes (Mullard, Amperex, Miniwatt, etc., not "ECG" with different-looking gray plates) have a nice round hole on the edge of both plate structures, plus seams on the top of the glass.
    -Brimar had round holes in plates, similar to Philips
    -Matsushita had seams on top of the glass (Mullard-style).

    I'm sticking to my original Japanese Raytheon guess. Let's hear from the experts, please!

    - T

    Hey, how do they perform? Do you like them?
     
  16. rockon1

    rockon1 Member

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    They sound pretty good in my JSX. Smooth overdriven,warm and punchy.Better I think than my JJ combination but maybe its in my head.Not instantly amazingly better though or I wouldnt be wondering if its phsycological! BTW- The 64-33 I was thinking perhaps meant the 33rd week of 1964?
     
  17. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Perhaps. That's likely - at least it fits in with the plausible time scenario. Raytheon began making gray plate 12AX7s in '62, but they were still the longer plate version (that I believe Mike sells at KCA). I don't know if all Raytheon gray plates were made in Japan, but later versions definitely were.

    - T
     
  18. rockon1

    rockon1 Member

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    Well at any rate these are the first old stock tubes Ive tried. After more testing I am convinced they make almost all of my amps sound better.They seem to add more fullness,thickness,body(something of that nature) to the overdriven tones.Not a ton but enough to notice. My old Crate Stealth head loves em. The JSX and Ultra also seem to have a tad more "body" is the only way I can describe it. Damn it I think I believe in the old stock.....say it aint so!:eek:
     
  19. brad347

    brad347 Member

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    rockon1, it's true. Now just see if you can get ahold of a Mullard 12AX7 or something. Mullard in v1 of my Deluxe totally changed my world :)
     
  20. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Its not a religion, though it may seem like it sometimes. Just follow your ears on to higher ground/richer sound.

    ... and not just any Mullard 12AX7 - I highly recommend going straight to the long-plate version(s). You'll never find any others that are "better" - a rare few are just as good, but with different character.

    - T
     

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