why balanced power last before component?

It is a nice list of customers, but I think there is more to it than that.

I've read stuff off of their website but I see troubling comments. Here is one:

Can the problem of AC noise common in Class-A tube amps be addressed? How about noisy guitar amps?

The answer is of course 'yes' (BTW this is in the article 'lifting the ground', http://www.equitech.com/articles/enigma.html).

Fixing the problems in the quote is easy through proper grounding, and its not rocket science. I have found that a lot depends simply on whether the designer knows what he is doing or not- and has nothing to do with the AC power (and apparently, nothing to do with whether the designer is an engineer for a pro audio company or high end audio). A lot of noisy guitar amps are simply that way because they don't ground the circuit and the chassis properly. Class A amplifiers, FWIW are no more prone to noise problems than any other amplifier as the quote suggests. When I see stuff like this it makes me suspicious.

Indeed, further down we have this comment:

The power resembles a balanced audio circuit or an XLR input from an unbalanced to balanced audio transformer.

This is not true. If you want to do balanced, the thing you **don't** do is use a center tap! The reason is as I mentioned earlier- you reduce the CMRR figure significantly simply due to the fact that the center tap is not in fact at true center.

So when I see stuff like this I begin to wonder- does this guy know what he's talking about? Apparently he knows power but not balanced line operation...

What I am seeing here seems to boil down to this: If the equipment has design bugs in its grounding scheme, the balanced power will help. If the equipment has no grounding bugs, there will be no improvement.

This has everything to do with the fact that if the audio equipment is grounded correctly, there will be no current in the ground connection. IOW if there is current in the ground connection, you have a problem!

FWIW I have followed some threads on some of the grounding products like the Entreq Tellus. I did a survey of owners, who I asked to do some measurements for me. What I found was that in 100% of the cases where the owner reported an improvement through the grounding system, the audio equipment associated had a grounding problem somewhere in the system. I may be jumping to conclusions here but I am thinking the same thing is going on with balanced power. Its there to fix bugs in the grounding design of the associated audio gear.

IMO if there are such bugs in the audio gear, it should be fixed (whether the designer knows how to do that is another matter altogether). This will solve more than just AC power issues- it will also solve ground loop issues.

Atma, instead of being troubled or suspicious, neither of which sounds like fun; why not turn your 'concerns' into profit?
It sounds like you have a solution for which the need is there. People are obviously spending (wasting?) money on relatively expensive Equitech products to cure the problem-as you describe it. Why not earn good money by tutoring all the designers (you infer there are many) in what you have said is the relatively simple art of proper internal grounding? Or, offer a custom service of rectifying inadaquate/faulty grounding schemes in noisy amps? Since one can easily spend $3000+ for one of Equitech's balanced power products I'm confident many owners would prefer to pay you to fix the problem at the source.
Again, if you don't know how Equitech ( the only one I'm familiar with) balanced power solutions for AC current effect a very significant reduction in line borne power distortions-which benefits the power supplies of ALL audio gear transistor or tube- you may find reading the Equitech technical information to be enlightening. It's interesting you find the problem of AC line borne pollution/noise so simple. I quote ANGELO BAGGINI'S book-HANDBOOK OF POWER QUALITY- "power quality is apt to waiver". Seems to be a huge problem for many. Also, if MARTIN GLASBAND doesn't know about balanced power-I'd like to know who does.

Atma, as a follow up, in Baggini's book there is a section titled
MONITORING POWER QUALITY. In it Andreas Sumper & Samuel Galceran-Arellano open by stating "power quality phenomenon are physical phenomenon that, in many cases, are APPEARING AND DISAPPEARING ARBITRARILY (not based on reason or evidence)." This arbitrariness is something that definitely bothers lesser designers than yourself; so it looks like there is a profitable business opportunity; perhaps a global one. Best regards, Peter.

I have found that designers in this industry often do not like being told that they have introduced a bug in their product.

The way you ground audio equipment BTW is simple: the circuit ground in the gear is kept isolated and insulated from the chassis. This includes the input and output connections. The chassis is directly grounded to ground through the AC cord. The audio ground is then referenced to the chassis through a resistance, one that is large enough to prevent any significant ground currents. In this way the equipment will not put any current though the ground and will be immune to ground loops.

Its simple- not rocket science, but you would be amazed at how many designers have not sorted this out. As a result there is a lot of snake oil out there dealing with the aftermath of poor grounding, and its not limited to high end audio.