Chasing 60 hz hum

Al,

Here is an interesting post that ran over on AA.
Note the responses of the equipment manufactures.

Plain and simple good sounding equipment can be built without the need of an equipment ground if the manufacture would only spend a few extra bucks and use double insulated wire for his AC power.

Floating ground... Does it cause damage?
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Jim

Thanks, Jim.

I've never been able to figure out how to navigate through long threads at AA in an efficient non-confusing manner :-), and in trying to do so in the thread you linked to I just encountered a lot of disagreement and arguing.

In any event, my point is that while good sounding equipment can certainly be designed and built without making circuit ground and safety ground common, the fact is that many designs do have them in common. And I would expect that modifying an EXISTING design to isolate the two grounds from each other might not be simple to do, and may have adverse sonic effects.

Best regards,
-- Al

I've never been able to figure out how to navigate through long threads at AA in an efficient non-confusing manner :-),
11-09-11: Almarg

LOL..... That's why it's called the Asylum....

Try this, it might be a little easier....

http://www.audioasylum.com/cgi/t.mpl?f=amp&m=156311
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Thanks again, Jim. I read through the entire thread, which unfortunately fails to reach consensus, due as I see it to personality conflicts getting in the way of what could have been very constructive exchanges. Which is particularly unfortunate considering the impressive backgrounds of several of the participants.

In the end, I'm left with the feeling that simply double-insulating the ac wiring and isolating safety ground from chassis could very well be a solution that can be directly applied to most if not all designs without sonic penalty, but the thread would seem to leave at least a little bit of doubt about that.

Best regards,
-- Al

Ralph, isn't that very commonly done intentionally, notwithstanding the fact that it creates the ground loop issue you are describing? And if so, wouldn't a fix (a)be likely to be hard to implement, and (b)be likely to degrade the integrity of the internal grounding scheme that was intended in the design, thereby affecting sonics?

Al, if something like that is done with intention, it can only be out of ignorance, like the kind that existed (and was excusable) 40 years ago. Nowadays you can't get away with it!

On top of that, it **compromises** the sound rather than improving it. Another way of looking at that is that audio components really don't like to be grounded on account of noise in the AC ground and also because of ground loops. If, OTOH, the ground *floats* at AC ground potential, the noise issue is gone and so is the ground loop issue.

Years ago I was of the opinion that a preamp is the place where the chassis and circuit ground being the same was acceptable (this is the way most pro-audio systems are done, although instead of the preamp we are talking about the mixer), but have come to realize that if some other part of the system has incompetent grounding, then the preamp is unfairly implicated. On top of that, if proper grounding technique is observed, you will notice right away that the noise floor is improved (for example, less hiss in a phono circuit) and of course there will be no need for exotic and possibly dangerous external grounding schemes.