Wow I've certainly learnt a lot reading this thread. Mostly how people can be so stupid around the world!
First, can I suggest people (who are in "who knows" part of the world) specify their mains supply when they start to talk about mains. Then readers know whether they are in a part of the world which allows you to easily "flip" your mains polarity by rotating your mains plug 180 deg (like the US) of does not (UK, Oz, NZ etc.) because it uses 3-pin plugs.
Secondly, how can people's logic be so different in different parts of the world. After all, we're all homo sapiens!
The mains supply has an active, a neutral and, in most places, an earth. Active is the wire that will kill you so it makes sense ... to use red for this. Then, some decades ago in Australia, anyway, some dickhead public servant said, because red colour blindness is a common affliction, the active line should be brown instead. They also changed the neutral to blue - ie. instead of red/black we now had brown/blue.
I would have thought that perhaps colour blindness should be a contra-indication of a career as an electrician - in just the same way that, if you're blind, you don't contemplate a career as an airline pilot - however, stopping someone from being an electrician is discrimination of the basest kind, so of course will not be tolerated. And as we can't have electricians wiring up incorrectly - because this might kill innocent citizens - we MUST change the colours!
Anyway, after the previous colour choices, to me green makes sense for the colour of the earth wire ... earth... grass... green etc.!! By all means use white as the neutral - instead of the original black and subsequent blue - but to select green as the neutral, to me is bizarre.
Now, while I'm on a good rant, I may as well get onto this topic of mains orientation. Marty DeWulf's article clearly explains how to go about the task of testing what your voltage difference is between the chassis and the wall-socket earth. It explains how you then reverse this (more difficult in 3-pin countries than the US ... you have to make up a short "extension cord" which has the active and neutral reversed, just for this test) to see which way round has the lowest reading.
And remember, when you do these tests, you have to make sure that temporarily, the earth pin on your power cord is NOT connected to the earth in the wall socket (if you have one). The easiest way to do this in Oz in to interpose a "double adapter" between your component power lead and the wall socket ... having disassembled the double adapter and removed the earth contacts!
So I am amazed at the questions and comments which have arisen, which plainly show the posters were not able to understand Marty's article.
What you are interested in here is the orientation of the power transformer primary winding vis-a-vis the mains active and neutral wires. If the lowest voltage connection was obtained when you had the wiores reversed, you need to swap the transformer primary windings around - you DON'T reverse the active and neutral wires on the IEC socket as this will take the fuse out of the active side ... not a good idea!!
Now, on the surface (and particularly to the sort of EE types who said 20 years ago that "a bit is a bit is a bit" ... so all CD players must sound the same!), the whole idea of "correct" AC mains orientation giving better sound seems garbage. However, it's to do with the way the power transformer is wound. If you're sceptical, just try it out ... then, when you become a believer, make sure all your mains switches are DPDT, like Occam, so you can readily flip the AC and listen to the difference!
Regards,
Andy
