need help identifying these units

Discussion in 'Tube Audio' started by gerjamr, May 14, 2018.

  1. gerjamr

    gerjamr Member

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    56
    I picked these up at a sale, they have no markings anywhere.

    1 = mullard 12ax7, mullard el84/6bq5, mullard 6x4

    2 = mullard 12ax7, 448?, sylvania 6x4

    Would these be decent mono amps to rebuild for a beginner?

    Thanks.
    Dan
     

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  2. radioactive

    radioactive tube gear fanatic Subscriber

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    a picture is worth a 1000 words
     
  3. gerjamr

    gerjamr Member

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    by bad
     
  4. Lavane

    Lavane AK Subscriber Subscriber

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    Octal cap cans?
     
  5. s-petersen

    s-petersen Scott Subscriber

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    looks like a record player amp, or a standalone speaker amp. single ended 3 watts or so output.
    volume bass and treble likely. RCA input
     
    soundmotor likes this.
  6. gerjamr

    gerjamr Member

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    Is that a brand? Sorry.. I don't know what that is.
     

     

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  7. s-petersen

    s-petersen Scott Subscriber

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    not a brand, a type
     
  8. gerjamr

    gerjamr Member

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    Soldered or socket? these are socket
     
  9. s-petersen

    s-petersen Scott Subscriber

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    Another possibility could be a movie projector amplifier
     
  10. Palustris

    Palustris Well-Known Member

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    Those look like they would be the perfect vehicle for the audio experimenter to learn about tube audio amplifiers. They appear to be single ended 6BQ5 amplifiers and you have two for stereo. They should put out several watts, but you will have to be willing to experiment. You will need basic tools like a soldering iron and multi meter. Maybe this article will inspire you: A Beginner 6BQ5 SE Amp.
     
    RWood likes this.
  11. gerjamr

    gerjamr Member

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    56
    Thank you all for the replies! I would like to have 2 amps, use as much of whats there as possible. I would like to make new chassis for them so I can arrange things to be more pleasing to the eye. If someone has done something similar with pics that would be great!

    Palustris, thank you for the link! I will be reading up on this.

    Thanks
    Dan
     

     

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  12. primosounds

    primosounds Parallel single ended EL84 ,EDCOR OPT

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    Sorry, i can not help you with the id'ing of these little amps, but i do know that they can be very good sounding ones after rebuilding, and well worth the effort and expense. I don't know if you have any experience doing that but if you have high efficiency speakers, like Altec or Klipsch, of around 100db, the sound from little single ended el84 amps can blow you away. It would be great to get them singing again. About the hardest thing to deal with is the plug in octal based can caps. No one makes them anymore and i am not sure if you can get them rebuilt. Perhaps, they can be but i don't recall anyone rebuilding that type. But it is not a big deal removing the socket and using a JJ multi value cap. cheers.
     
  13. gadget73

    gadget73 junk junkie Subscriber

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    I'd probably give some consideration to turning these into a DGSE1. The tube lineup is suitable if you plan to rebuild these on another chassis.
     
  14. knockbill

    knockbill Addicted Member

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    +1... I would want to get them working as original first, tho,,, just to make sure the components(tubes, TX etc) were working... May just need a few caps, or resistors, and a variac to bring em up slow ...
     
  15. gerjamr

    gerjamr Member

    Messages:
    56
    Thanks everyone!
    I have a pair of heresy's so I have that covered, I also have a variac and thought about turning them on but someone cut one side of the resistors in the back of each one, hard to tell in the pic but it's a large light green one and a smaller brownish one in the same spot on the other amp so I sure about turning them on.
    Could I remove all the tone control stuff and replace the cap cans with some different type and keep everything else in its place for now to test? It looks like with the controls gone it would be a bit less " scary " under there!

    Thanks
    Dan
     
  16. s-petersen

    s-petersen Scott Subscriber

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    I wouldn't modify them before getting them running, it would make things more complicated to figure out, weather a problem is old, or new.
    Looking at the pic, it looks like the first resistor powering the unit is disconnected, the can caps may be shorted, or something, it looks like the HV is disconnected. A better pic of the area would help. The large greenish Tru-Ohm and the brown resistor on the other amp, are disconnected Correct?
    The brown wires out of the back are the speaker wires.The RCA jack is the input.
    If you have a variac, or DBT it would be a good thing to use.
     
    Last edited: May 17, 2018 at 9:12 AM

     

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  17. gerjamr

    gerjamr Member

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    Got it! I have to put this om the back burner for a bit , thanks for the help!!

    Dan
     
  18. chinacave

    chinacave Its Like a Jungle Sometimes; It makes me Wonder Subscriber

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    !! The one on the left in your 1st picture has a simply epic 'Tested' stamp on it.

    That is far + away the largest one I have ever seen outside of a beef aging cooler!

    Fun project!
     

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