Grounding ?

Bob_R
I believe your statement would be true IF there were no hot/neutral reverse wiring. I do NOT mean the outlet, the condition of which is easily seen with an easily purchased outlet tester, but internal to each piece of gear. Does that make any sense?

There can only be current flow if ground potential is different between each piece. An easy way to determine this would be to plug everything in than measure chassis-2-chassis with a decent DVM.

Given the sensitivity of the gear involved, there doesn't have to be much current, either.

If you're really paranoid you can simply connect the chassis of the primary grounded component (typically preamp) to the chassis' of other componentry. Any reasonable size (black insulation color for appearance) (14awg & stranded for flexibility) household electrical wire with spade or ring tongue crimp lugs should be more than sufficient. Basic creativity should suffice; loosen a chassis screw on the back panels & tie the lugs thereto.

However if it was me I absolutely wouldn't bother (take a hint from Milimetr) but I would never advise someone else against safety grounding for liability reasons alone. Perceive the implication, vs. the statement. In regard to sound quality now that's the issue, which many might be more likely to focus on.

Yes you can simply voltmeter-probe to the chassis, with the other probe referenced to an AC outlet ground, to check for stray leakages. The compoment would be energised but not cabled to anything else. You need to probe on a bare metal surface or press the probe tip down hard to penetrate the paint; judiciously of course and in a strategic location (such as the bottom panel) so as not to harm the finish.

Bob_b
Yes I am paranoid, but that doesn't matter in this case.
My personal system has NO hum or other internal noise issues.

My recommendation is to check NOT to ground, but between system components. IF there is voltage present, I would consider swapping hot/neutral where the power pigtail gets to the first terminal strip or whatever.
Once everything agrees, the hum should disappear?

My recommendation is to check NOT to ground, but between system components. IF there is voltage present, I would consider swapping hot/neutral where the power pigtail gets to the first terminal strip or whatever.
08-10-09: Magfan

If there is a difference of potential, voltage, from one chassis to another then there would indeed be a current flow when the two chassis are connected together by ics.

If the AC polarity is reversed and not correct on a piece of equipment that could cause a higher potential, voltage, from that piece of equipment to another piece of equipment where the AC polarity is correct. I would think the difference of potential would be there whether an equipment ground was used or not. Jmo.....

Something that should be made clear when measuring AC leakage of the primary winding of a power transformer the measurement is actually referenced to the neutral conductor.... The neutral being the grounded conductor which shares the same ground plane as the equipment grounding conductor. That is why most people measure from the chassis to the equipment ground of the recept. But the actual difference of potential is being measured to the neutral.
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Exactly, J,
there will be voltage present if the ground plug is used or not! Connecting 2 pieces under these conditions is using 1 of 'em as 'local ground'.

Please explain 'leakage'. I have heard the term but am unfamiliar with its use in this case.

Have I just been lucky all these years in NOT ever having a bigtime hum problem?