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In the Forum: Analog Playback
In the Thread: The last phonocorrector: “End of Life" Phonostage

Post Subject: The ShieldPosted by Paul S on: 1/23/2012

N-set, I don't know much about the theory, but maybe you have focused on "uniform ground potential" while neglecting the effects of EMF? (Not to mention the EXTREME difficuty of maintaining a "single", non-reactive "ground path" in the first place...) Again, I keep the chassis/shield(s) and the signal grounds electrically separate just because it reduces noise. Yes, the differences in potential are there in both cases; but for me the bleeder can be arranged to address the audible part of the problem. Again, the signal ground is the line neutral, and the chassis/shield goes to the dedicated ground (and NOT the line ground). And remember, you want to solder or tightly clamp your bleeder to clean, solid, well-grounded copper, not chrome, nickle, etc.

By the way, FWIW, it may be the case that your AC system includes a ground wire, after all, despite the 2-prong plugs/outlets. In many older systems a ground wire is stubbed inside outlet, junction and switch boxes; and in some older systems the ground wire is stubbed at each box, but it is "made up" just outside the box. Of course, the problem of line noise via inductance (if nothing else..) is usually present, in any case, when the house ground is considered, as such.

Best regards,
Paul S

PS: You might well find it best to 2-prong your amps and to only "bleed" the front end...

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