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Silvertone 1481 mods...

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  • Silvertone 1481 mods...

    I acquired this 1481 some time ago...

    Click image for larger version

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    A little ratty but works ok.

    First mod... new speaker and baffle...

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    If it ain't broke I'll fix it until it is...
    I have just enough knowledge to be dangerous...

  • #2
    Original speaker needs a re-cone...

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    Original baffle is quite rough...

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    If it ain't broke I'll fix it until it is...
    I have just enough knowledge to be dangerous...

    Comment


    • #3
      I found some schematics on line but they all have the same mistake...

      Click image for larger version

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      Re draw of the schematic...

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      If it ain't broke I'll fix it until it is...
      I have just enough knowledge to be dangerous...

      Comment


      • #4
        Inside is fairly clean...

        Click image for larger version

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        If it ain't broke I'll fix it until it is...
        I have just enough knowledge to be dangerous...

        Comment


        • #5
          Added 3 wire power cord and clipped the death cap...

          Click image for larger version

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          Unhooked the original cap can and added 3 new electro caps for the power supply...

          Also added a speaker jack...

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          If it ain't broke I'll fix it until it is...
          I have just enough knowledge to be dangerous...

          Comment


          • #6
            After much experimenting I ended up with these circuit mods...

            Grid stoppers R3, R7, R11

            Bypass caps C2, C5

            Compare to original schematic redraw above...

            Click image for larger version

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            For reference:
            B+ 275V
            Screen 260V
            Pre 160V

            HTR 6.4 AC

            The mods turned this amp into a distortion monster...

            Maybe not everyone's cup of tea, but I like it.

            The grid stoppers are ABSOLUTELY necessary, as the amp will squeal and oscillate without them.

            Sorry no sound clips, I have no way to record it.

            Pic of the mods...

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            Last edited by galaxiex; 05-05-2019, 06:41 PM.
            If it ain't broke I'll fix it until it is...
            I have just enough knowledge to be dangerous...

            Comment


            • #7
              Now I'm looking for an 8 ohm output transformer as the original died, (truthfully, I damaged it) so I installed a Champ replacement TX that is 3.2 ohm.

              The Warehouse speaker is a 4 ohm, but I'd like to be able to plug this into an 8 ohm cab.

              Also 8 ohms would give me more options for the in-cab speaker.

              Any suggestions for an 8 ohm output Tx?

              Thanks!
              If it ain't broke I'll fix it until it is...
              I have just enough knowledge to be dangerous...

              Comment


              • #8
                I have a mulched silvertone chassis around here somewhere. I think the tx's are ok. Not sure if it's single ended though. I'll check tomorrow.
                Originally posted by Enzo
                I have a sign in my shop that says, "Never think up reasons not to check something."


                Comment


                • #9
                  Thanks g1.
                  If it ain't broke I'll fix it until it is...
                  I have just enough knowledge to be dangerous...

                  Comment


                  • #10
                    Some of the Silvertones (or was it Airlines?) had a 4 and 8 ohm output, the unused wire was left hanging.

                    Comment


                    • #11
                      Sorry, what I have was a 1472 (push-pull with 6V6's).
                      Originally posted by Enzo
                      I have a sign in my shop that says, "Never think up reasons not to check something."


                      Comment


                      • #12
                        Originally posted by g1 View Post
                        Sorry, what I have was a 1472 (push-pull with 6V6's).
                        Thanks for checking.

                        I have ordered a Mojo 771 Tx.
                        If it ain't broke I'll fix it until it is...
                        I have just enough knowledge to be dangerous...

                        Comment


                        • #13
                          I recently sold a ratty (but completely functional.. even the reverb worked) 1484 w/ the original speaker cab for $400. They are a one trick pony.... but they do that trick fairly well. The guy that bought it loved it. (I remember putting lots of them in the dumpster because they weren’t worth returning at the time, lol) If there is room I would suggest putting a 12” Eminence in it. Then you can use a tube screamer without cooking the voice coil and have a bit of bass response. Thinking that you will get better performance with a Mojo transformer seems a bit optimistic to me.. but whatever floats you boat.

                          Comment


                          • #14
                            Originally posted by olddawg View Post
                            I recently sold a ratty (but completely functional.. even the reverb worked) 1484 w/ the original speaker cab for $400. They are a one trick pony.... but they do that trick fairly well. The guy that bought it loved it. (I remember putting lots of them in the dumpster because they weren’t worth returning at the time, lol) If there is room I would suggest putting a 12” Eminence in it. Then you can use a tube screamer without cooking the voice coil and have a bit of bass response. Thinking that you will get better performance with a Mojo transformer seems a bit optimistic to me.. but whatever floats you boat.
                            The Mojo transformer is so I can use 8 ohm speakers or plug the amp into an 8 ohm cab.
                            More options are available in 8 ohm speakers, compared to 4 ohm.

                            With the 3.2 ohm Champ Tx that is in there now, it doesn't like an 8 ohm load.
                            If it ain't broke I'll fix it until it is...
                            I have just enough knowledge to be dangerous...

                            Comment


                            • #15
                              Originally posted by galaxiex View Post
                              The Mojo transformer is so I can use 8 ohm speakers or plug the amp into an 8 ohm cab.
                              More options are available in 8 ohm speakers, compared to 4 ohm.

                              With the 3.2 ohm Champ Tx that is in there now, it doesn't like an 8 ohm load.
                              Yeah... I get that. I just meant there is pricy and pompous iron out there. If you like it.. that’s what matters.

                              Comment

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