Yet another grounding query

Discussion in 'The Squawk Box' started by Leña_Costoso, Aug 30, 2017.

  1. Leña_Costoso

    Leña_Costoso Senior Member

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    The last amp I built was over ten years ago. I think I'm up to number 12 or so, with this new Super getting under way.

    Reading about, I see the famous brass plate going out of fashion, and the ground "buss wire" becoming all the rage in tweed based designs.

    With all the amps I've fixed for folks over the years, I've never had an issue with the dread "corroded" brass plate. I'm sure it can happen, especially with todays brass being what it is, with its lower copper percentage/higher zinc percentage.

    What say other builders out there? Yah, I know not the best forum on planet earth to ask this question... just curious for multiple opinions :)
     
  2. Soul Tramp

    Soul Tramp Speaker Snob MLP Vendor V.I.P. Member

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    Corrosion is only part of the problem. The real issue with the old style grounding is that it results in a horrible ground schema. Very noisy! I use a floating star ground schema on my amps.
     
  3. Leña_Costoso

    Leña_Costoso Senior Member

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    Never had noise issues, but I did things a bit differently. All the ones I did had the plate soldered to the chassis at both ends. This time around, I don't have a plate, but do have .020 2-1/4" (65mm) copper foil - not brass.

    Whatcha think about a wave wire buss, just wavy enough so you can push it out of the way to do a repair if needed?
     
  4. Cjsinla

    Cjsinla Premium Member

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    I'm also going to build a Tweed Super, ordered all the parts. What is a floating star grounding scheme?
     
  5. Soul Tramp

    Soul Tramp Speaker Snob MLP Vendor V.I.P. Member

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    The chassis is completely removed from the ground schema and is only used as an EMI shield. The floating ground separates earth and ground. The star schema lets you ground separate functional components of the amp in a way that makes sense from an electron flow.

    There is a great deal of ground loops in conventional amp layouts. The old Fenders (and others) of the 50's, 60's & 70's had horrible ground schemas. This creates internal noise and allows external noise (EMI & guitar) to enter into the signal path.

    Google Floating ground and star ground for more specifics. It's a lot more typing than I'm up to.
     
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  6. Cjsinla

    Cjsinla Premium Member

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    Good info but very technical. I think I understand some of the basics.
     
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