[ProAudio] Muncy Revisited: Pin 1 to chassis through a capacitor?

[Bob Katz]

I like it, John. It’ also more of a star ground approach and it takes care of the pin 1 issue at the same time!

As for the “AC side” versus the “DC side” of the 0 V line inside the power supply, the schematic shows it to be a continuous trace from One side of the Board to the other so I’m not sure of the distinction if any unless we’re looking at micro currents I imagine. 

The two “0 v” points at the AC entrance of the ps board are just two adjacent screws of a terminal strip tied together. I should have shown them as tied together

Bob 


My iPhone made me write this. Quotes only below this line. Nothing more to see here. 
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> On Dec 2, 2023, at 1:08 PM, John Chester via ProAudio <proaudio at bach.pgm.com> wrote:
> 
> On 12/2/23 12:21 PM, Bob Katz via ProAudio wrote:
> 
>> Naturally, I started a firestorm on facebook asking a question about grounding in a headphone amplifier I'm building.
> 
> 
> A ground loop running through both the headphone amp and the power supply board doesn't seem like a good idea to me.  Here's my revision of your diagram:
> 
> https://photos.app.goo.gl/gWfABiqTc82mKZLV9
> 
> I wouldn't opine on whether the ground loop will upset the power supply without seeing both the power supply schematic and the PC board layout -- assuming it's not a potted blob.  Best to just get rid of the ground loop.  Zero volts to chassis ground should be on the DC side of the power supply, never on the AC side.
> 
> Zero volts to chassis should occur before the zero volt line gets to the headphone amp, not after.  IMO the most cautious approach to power supply wiring would be to run 3 twisted wires from the power supply to the chassis ground point, where the zero volt line gets connected to chassis, and then continue with 3 twisted wires to the headphone amp board.
> 
> -- John Chester
> 
> 
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