Gibson GA-5 // creative grounding 101

wow // strangest grounding I’ve ever seen maybe … main filter cap GND is going to tube rectifier socket, from there to power tube socket to provide GND for grid bias resistor and one side of filament circuit, thru filament leg to 12ax7 socket and to signal GND line to input jack ring lug and finally grounded THERE to the chassis … (LOL, re-did the whole scheme) … great sound going into my ’68 4×12 cab with 25w greenies // minimal hum …



2 comments on “Gibson GA-5 // creative grounding 101
  1. Nick Fryer says:

    Hi!

    I have a gutted GA-5 Chassis and want to rebuild it to original spec. Do you have a copy of the wiring diagram from above that you could email me? I am a novice builder and could use all the help I can get. Any other advice in regards to the GA-5 would be helpful also. I knew that the grounding scheme was interesting on this one so I am glad to find your blog. I can mostly make out everything on the wiring diagram but a couple of things are a little unclear ( i.e. where is the 22k and 10k res between the filter caps?). I am going to study up on it more and compare it to my schematic. So happy to find this diagram. I am going to draw my own for learning purposes but it is nice to have some to check from.

    Thanks!
    NF

  2. Nick Fryer says:

    Just found the 10k 22k BTW…..one of my big problems is going from schematic to layout and imagining how it all should be laid out.

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