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  • Unknown amp

    I recently received the guts of an amplifier and am trying to find a compatible schematic. The amp is very simple (like an early Champ) with one volume control knob (with on/off switch) and no tone control. The tube compliment is 6V6, 12AX7 and a missing tube. I believe the rectifier is 6X4. It is not a transformerless "widow maker" amp since it has a power transfomer.

    I compared it to the SilverTone 1481 and it is close.

    Let me know if you can think of another amp that uses that compliment. Thanks.

  • #2
    no pics?
    nosaj
    soldering stuff that's broken, breaking stuff that works, Yeah!

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    • #3
      Does the rectifier have it's own heater winding, or is it tied to the same heater winding as the other tubes?
      Originally posted by Enzo
      I have a sign in my shop that says, "Never think up reasons not to check something."


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      • #4
        Well I was going to ask for a photo, but I think you might have provided one if you thought it would help. Cosmetics can be a give away for all the various amps of the era. Alas, you only have the guts.

        Still... Is it clearly a factory made product by the looks of the face plate, build practice, etc? Or could this be an early kit or DIY? Kay, Supro, Silvertone, Harmony, Kent and many other amps (even Gretsch) were often made by Valco. There was another contender at that time too which made amps for some of those brands but not nearly as prominent as Valco and I can't remember the name. I think Supro was Valco's own as was "Valco". And I'm sure a lot of companies would have copied the "Champ" format of a 6V6, 12ax7 and a rectifier with the power switch on the volume. Maybe the Noval socket rectifier could help pin it down as somewhat unique? Nothing jumps out for me but you probably couldn't go far wrong looking at old Valco schematics in the "5 watt" class that aren't widomakers. Maybe something will pop up.
        "Take two placebos, works twice as well." Enzo

        "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

        "If you're not interested in opinions and the experience of others, why even start a thread?
        You can't just expect consent." Helmholtz

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        • #5
          I'd actually verify the missing tube is actually a rectifier tube.
          nosaj
          soldering stuff that's broken, breaking stuff that works, Yeah!

          Comment


          • #6
            If it's that simple can you draw a schematic? Our beloved Enzo once told me "it's just an amp." and I've kept that in mind ever since. It's also possible that it's a very old independent maker. I have a couple of those.

            The way I do it is to start with the power supply, draw that section from the plug to the B+ lines to the tubes, then the pre-amp, then the rest.
            --Jim


            He's like a new set of strings... he just needs to be stretched a bit.

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            • #7
              Originally posted by gui_tarzan View Post
              If it's that simple can you draw a schematic? Our beloved Enzo once told me "it's just an amp." and I've kept that in mind ever since. It's also possible that it's a very old independent maker. I have a couple of those.

              The way I do it is to start with the power supply, draw that section from the plug to the B+ lines to the tubes, then the pre-amp, then the rest.
              Yep. I do it differently (and I'll cover my method in a sec). But almost anyone here can doodle a basic triode amplifier circuit or power supply. With a simple amp like that it can't be too complicated. Three tubes, maybe thirty components, a pot, a switch and two transformers.

              What "I" do... I draw out the jack, controls, tube sockets and transformers in ink on a piece of paper where I think I'd want them for a schematic (though this usually gets modified a little for the second draft). Then in pencil I just connect the dots with whatever conponents are between points A and B as it were. Being able to erase allows me to modify the routings in the drawing ad hoc for better clarity later. Once I've drawn the amp out this way I can see it's workings more clearly in my mind and I create a schematic using that rough draft.
              "Take two placebos, works twice as well." Enzo

              "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

              "If you're not interested in opinions and the experience of others, why even start a thread?
              You can't just expect consent." Helmholtz

              Comment

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