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3 prong cord modification to the original 5f1 circuit

Discussion in 'Shock Brother's DIY Amps' started by Marn99, Nov 24, 2020.

  1. Marn99

    Marn99 Tele-Holic

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    So I am going to be building a '57 5F1 over the winter alongside my Rickenbacker 360 Capri build, and I just want to make sure that I am understanding how to modify the original circuit for a 3 prong plug correctly. That cap going off the fuse holder is the "death cap" yes? And the modification would be to omit the capacitor, solder the ground wire to the chassis, hot to the fuse, and neutral to the potentiometer, correct?
    5f1 death cap.png
     
  2. Peegoo

    Peegoo Poster Extraordinaire

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    Click on this pic:

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  3. Marn99

    Marn99 Tele-Holic

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    Okay, so how would I do this if I were using a SPST pot like the originals? Would it be the same circuit as drawn just with a ground wire soldered to the chassis and the death cap gone?
     
  4. D'tar

    D'tar Friend of Leo's

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  5. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    Yes, use The Force, use Rob's wiring diagram, and always always listen to @D'tar ... :)
     
  6. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    Yes, get rid of the cap.

    The modern electrical code would be to bolt the ground to a dedicated bolt on the chassis. Nothing other than the ground terminal, so it should not be bolted to the transformer bolt.

    As illustrated in Rob's diagram, the ground wire should be long enough to be the last to leave the chassis should the power cord accidentally exit the chassis.
     
  7. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    So many details. As LLC says, best (which is easy) is to drill a hole in the left end of the chassis (11/64; #8 bolt), then #8 swage-on ring terminal, crimp and solder, and attached to bolt with star washer under, keps nut on top, and loctite. And per UL, and as in Rob's drawing, this is separate from the amp power ground.

    33F895AC-84BA-4E2D-8BEB-1C01FC27ED8C.jpeg

    0CDFBC65-E982-43F9-9F56-3561DBF27BAF.jpeg

    upload_2020-11-25_14-6-58.jpeg

    You asked a lot of good questions actually. So in Rob's drawing, note hot to fuse (center) and then fuse side on to switch, then back to primary. The neutral splices straight to the other primary.

    One other note on Rob's 'best practice' diagram. Notice how the red/yellow HV center tap ties to the negative pole of the first filter cap? Easy, and reduces hum.
     
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