Magnavox Labeled Tubes?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by MT Buckaroo, Jan 27, 2015.

  1. MT Buckaroo

    MT Buckaroo Silver Supporting Member

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    So I was at my grandparents' house this past weekend in GA visiting my 104-year old grandmother, and stuck my head down in the basement where I saw an old record player/radio. Looked like a piece of furniture. Probably dates to the late '50s. Looked in the back and saw a slew of tubes (and some big arse speaker on a silver frame which I'm guessing was a 15" and alnico judging by the magnet cover).

    Pulled the tubes and came away with nine 6V6GT's all labeled Magnavox on the base (two quads were associated with the record player amp, and one 6V6 was with the separate radio receiver amp), two 5U4GA (not GB)rectifiers, two Magnavox 12AX7s, and some other little preamp tube which name escapes me right now (not anything I've ever seen in guitar amps).

    I haven't tested them as yet, and they may all be shot, but for the NOS tube gurus out there, what do I likely have? Pics to follow in the pm.
     
  2. slider313

    slider313 Silver Supporting Member

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    Magnavox, like many other companies, bought tubes from many sources and put their name on the glass or base. Only a picture can confirm what you have.
     
  3. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Without any codes or photos, it is not possible to conclude the manufacturer(s). Let's see some nice clear, close shots.

    - Thom
     
  4. Structo

    Structo Member

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    What condition was the radio in?
     
  5. DaveKS

    DaveKS Member

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    Yep pics.
    Here's my Magnavox labeled Tungsol, note the 322 EIA code denoting Tungsol as supplier.
    [​IMG]

    You can see the 322 here, not always the definitive answer but a good place to start.
    [​IMG]
    One of the best sounding 12ax7 in my stash, she's a special snowflake of a tube.

    And CBS 6v6 note the 210 EIA code, that's CBS/hytron EIA code.
    [​IMG]
     
  6. MT Buckaroo

    MT Buckaroo Silver Supporting Member

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    Thanks, guys. Pics to come.
     
  7. MT Buckaroo

    MT Buckaroo Silver Supporting Member

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    OK, so here's what I got. Turns out my initial assumptions were a bit off due to not looking closely (and the dust coating). I don't have nine 6V6GT's, I have eight. One of those that I thought was another 6V6 that came out of the radio section along with a 6U8 in fact appears to be a 5Y3, but I need help confirming. See below.

    Tested all the tubes on my B&K 700. The 6U8 is shot, and the two 12AX7s (long black plates with 12AX7 in a little elongated octagon at the top of the getter, marked 57-30? and something else under that) are also no good. Two of the 6V6's are no good (but that leaves me with a pair and a quad). The 5U4GA's both test good.

    Here are the pics. I have:

    a quad of these (smoked glass)...

    [​IMG]
    [​IMG]

    a pair of these...

    [​IMG]
    [​IMG]

    two of these...

    [​IMG]

    and here is the mystery 5-pin rectifier (?) tube which I haven't put on the tester yet pending positive ID...

    [​IMG]
    [​IMG]
     
  8. slider313

    slider313 Silver Supporting Member

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    The 188 code is GE
    The 280 code is Raytheon
    The 312 code is Sylvania
     
  9. DaveKS

    DaveKS Member

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    Yep and those all look correct on inside or etching for those I believe except for Raytheon, I've no experience with them. Did they make grey glass?

    Heres a manual on EIA codes if you want to keep it for futer reference. Not always definitive but good place to start.
    https://www.dropbox.com/s/hmciyb8cwrhzb1h/EIACODES.pdf?dl=0
     
  10. slider313

    slider313 Silver Supporting Member

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    Yes, Raytheon did make grey glass 6V6's.

    [​IMG]
    [​IMG]
     
  11. MT Buckaroo

    MT Buckaroo Silver Supporting Member

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    Thanks again, guys.

    Any idea on the type of the "mystery" tube - the 2 last pics, about the size of a 6V6, 5 pins, Sylvania manufacture...?? Can anyone tell from the shape of those getters what this is?
     
  12. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    It looks like a Sylvania 5U4GB

    - T
     
  13. Blue Strat

    Blue Strat Member

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    ^^^ Probably a Sylvania 5Y3GT (same size as a 6V6GT).
     
  14. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Could be a 5Y3GT - yes, that's smaller than the 5U4GB. It definitely has the plates of a full-wave rectifier.

    MT Buckaroo: look at the domed top of the glass, under direct sunlight, to search for visible traces of print.

    - T
     
  15. MT Buckaroo

    MT Buckaroo Silver Supporting Member

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    5Y3GT it is. HOLY COW that was some faint lettering! Tests fine. Thanks all.
     

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