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  • New build grounding questions

    This is my 1st attempt at building a larger amp 50W. I have built several smaller SE and PP amps in the past. Using the Fender Vibroverb AA 763 as a platform minus the vibrato but keeping the reverb, all as a single chan amp. I'd like to use a Star ground scheme where I place the PS filter caps in the section they feed and using their neg side as the Star point for the section. My 1st two caps prior to the choke, supply the OT CT and pwr tube plates and are grounded together as in the fender. Added to their neg side I'm wiring the main transformer secondary ct's (main power & filiments). The 2nd node cap which follows the choke, feeds the pwr tube screens and it's neg side is connected to the 1st two caps. These 3 caps will be physically located near the PT. The 4th cap which feeds the PI is in line with the others and grounded together. The last cap is physically located in the pre-amp section. All star points will be connected together and the chassis ground will be connected near the input jack (input jack gd connected here as well). My questions are: 1. should I ground the bias supply at the PI cap node? 2. How do I treat the reverb driver which gets it's feed from the pwr tube screens cap (it would take a long gd lead back to that cap)? I'm grounding the reverb recovery amp to the pre-amp sections filter cap. Hopefully you can follow this rambling. All advice/comments are appreciated. fg

  • #2
    Hi
    most respectable grounding articles ever read. Enjoy.
    Catalin

    http://www.valvewizard.co.uk/Grounding.pdf
    http://www.aikenamps.com/index.php/grounding
    http://www.geofex.com/Article_Folder...ing%20amps.pdf
    Last edited by catalin gramada; 04-07-2015, 10:51 PM.
    "If it measures good and sounds bad, it is bad. If it measures bad and sounds good, you are measuring the wrong things."

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    • #3
      Originally posted by frankeg View Post
      1. should I ground the bias supply at the PI cap node? fg
      All supply (HV, bias, heater) should be referenced to the ground. Do this directly to chassis with short wires preferable in the same point. You have no reasons to do a reference through a curent return path. doing this maximise the risk for loops or rising noise into signal path. This wires are not used to carry current through it.but also should be able to offer a strong low impedance path to the "earth" in case of fault for safety reasons
      Last edited by catalin gramada; 04-08-2015, 07:51 PM.
      "If it measures good and sounds bad, it is bad. If it measures bad and sounds good, you are measuring the wrong things."

      Comment


      • #4
        Thank you Catalin. I appreciate the reply! fg

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