Home Tweakers' Asylum

Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

RE: Power Cord Polarity

"Then why don't you just plug it in and see for yourself? You are the one that has to listen to it."

I was thinking along the same lines. Connect a turntable to it and find out which way gives you the least hum for one.

Things with two prong AC cords that are not polarized are usually fairly well isolated. But there is always a resistor and cap to keep the static electricity away. That causes a small amount of current to flow which can invade low level signals. Remember turntables ? In the owner's manual they told you if you are getting hum even when you got the ground hooked up to reverse the cord.

Things should be isolated enough that it doesn't matter, but nothing is perfect. And now, with a polarized AC cord, if they took and use the old resistor and cap on the hot side it would probably produce more hum. So then what do you want them to do ? If they put the resistors and caps o both sides of the lie there would be hum no matter which way you plug it in.

Maybe the answer is just to power all this stuff with DC.

A story about that, I think maybe in England. They used DC for a time. A serviceman was called because the TV would not work. He asked for a potato and stuck electrodes in it, and on DC one turns black or something. He simply reversed the power cord and it worked. I found it hard to believe they used DC, but then, whatever.

Really, with SMPS technology, DC power transmission is not all that much of a pain. It would eliminate all the inductive losses and the big heavy transformers. However, being solid state devices they would be more prone to failure and more susceptible to lightning strikes and whatever. But as technology advances and they fix those problems, we might see the day when power transmission is DC. It is possible now, but in the view of most people who now what they're doing, and I agree, it is not reliable enough at this point in time. There could be some changes made, for example huge filter capacitors that would limit their vulnerability to voltage spikes. Can't do that with AC.

But for now it is AC and is not going to change anytime soon. The whole system is designed for it and replacing it is like, well just too expensive.

Like electric cars. First of all nobody wants to just scrap their car and buy a Tesla. Then you need high current to charge the thing. If you are worried about CO2, more CO2 is emitted by generating electricity than cars, it would only make it worse.

France is said to be outlawing fossil fuel i about a decade. Well they happen to be a world leader in nuclear power. Ad if we start going electric we should have their engineers over here. I have never heard of them having an "accident". So they can pull this off. Thinking that the US is best at everything is an extremely outdated notion. In fact Russia has better weapons, we just have more of them. Other countries are doing things too and they are not all stupid.

So most of Europe is on 240/50 Hz. There was a discussion on Usenet on why the US went with 60 Hz. Most say it is so that the electric motors run faster and increase production in our factories. Of course that was many years ago. Now most machines run on DC and possibly a three (or more) phase convertor, or stepping motors.

Bottom line though, if people are worried about CO2, the only way to go is nuclear. Solar just isn't going to do it. Is solar going to power my AC at 240 volts at 15 or so amps in the middle of the night ? Ain't happening without a shit ton of batteries that are an environmental nightmare. Have any idea what kind of chemicals are in those things ? You certainly don't want them in your Cheerios.

Ironically, much of this old transformerless stuff will run just fine on DC unless you plug it in backwards. Might even run better. You make tube amps with DC filament supplies right ? Reduces hum and noise.

Enough.


This post is made possible by the generous support of people like you and our sponsors:
  Signature Sound   [ Signature Sound Lounge ]


Follow Ups Full Thread
Follow Ups
  • RE: Power Cord Polarity - JURB 20:51:21 08/03/17 (0)

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.