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old tube preamp

Discussion in 'Preamps / Channel Strips' started by drumist69, Aug 27, 2005.

  1. drumist69

    drumist69 Active Member

    I am looking at buying this as a tube direct box for recording guitars and bass at home. Would this work? Here's the specs...
    "This is a mono 15 watt amplifier, which was designed by Zenith for their 1950's high end mono Hi Fi phonographs. It has five tubes, including push pull 6V6 output tubes, with separate bass and treble controls, and a unique "Presence" control. The input and speaker jacks are 1/4 inch mono phone jacks, so it lends its use to a guitar amp, or a mono hi fi amp. The electronics have been completely restored, with new caps, and any weak tubes were replaced. Awesome sound! Includes service data. Will outperform any of the early Bogens!"
    The main thing I'm wondering about is the wattage. Will that wattage work as a DI? If not I'll probably get it anyway and build a small guitar amp for recording use. Any input on this would be appreciated! Thanks! ANDY
  2. Kev

    Kev Well-Known Member

    On paper it seems like this could work to do both duties.

    For DI purposes the Wattage is not so important and even though there is 15 W available, you don't have to use it all
    the power can be soaked up into a Dummy Load ... easy.

    It is possible with some input variations this could be used for Guitar, Line , and mic levels.

    The Mic conversion could be trickey and will require a transfomer ... and obviously phantom if you want to use Condenser Mic's

    Can we see a circuit diagram to this ??
    OR and inside picture ... both.

    can't really say anymore without more information.
  3. drumist69

    drumist69 Active Member

    I'll get a pic

    I don't have access to a diagram, but I think I can get an inside pic...let me see...
  4. drumist69

    drumist69 Active Member

    pic link

    Here's a link to the only pic I've got...should I try to get more info first? The thing's only $45 so I figure I can't go wrong. If nothing else I'll get some good first-hand experience in what makes tube amplification tick. That's a pretty beefy transformer, no? But, yeah, if I could mod this to work as a guitar and bass DI, as well as a mic pre, that would be awesome! Here's the pic...

    Could I use this in conjunction with the amp for phantom power without having to mod the amp?
    Then the only question would be how to set up a dummy load so I can drive the tubes, right?
  5. drumist69

    drumist69 Active Member


    The guy will send me schematics with the amp, so I figure I'm just gonna buy it and see what I can do with it! Thanks! ANDY
  6. Kev

    Kev Well-Known Member

    I think I see more of a small guitar amp than a Mic to line or DI box.
    It may well do both.

    Yes, that phantom box is one option.
  7. drumist69

    drumist69 Active Member

    I bought it!

    Well, I bought the ancient tube amp. I have a few friends who are well versed in electronics, but I may need to pick some brains here as well. Does anyone know any good links regarding this type of gear? I've found a few pages so far, but I have a lot of learning to do! Thanks! ANDY

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