Checking the quality of your AC

Zaikesman, your meter is telling you the average voltage on the line. The thing you can't tell is wether there is any superimposed noise on the line or fast transients, etc. You really need an oscilloscope to see if there are any problems like this. In my house, there just wasn't anything to see.

Thanks Bufus, I realize the voltmeter won't tell me about other AC problems, but I still wonder if voltage correction is really necessary from what I see (or don't see) with this meter.

Unless it's a recording 'scope, that's a lot of time sitting in front of it, just watching; and for what?
Bundus is correct. Rent or buy any one of numerous power quality analyzers, learn all about it, and check for goodies like THD out to the 50th harmonic.

Fact is, reviewers and mfgrs. have overhyped the "dirty power" story, the "EMI/RFI noise pollution" angle to death. For instance, I (like most people) live in a residential neighborhood, a planned condo development, and in fact have excellent power quality. There are no industrial or manufacturing facilities for miles and miles.

Shasta: I think that you are "somewhat lucky" if you don't have any form of industry near you and your neighbors aren't generating and pumping electrical hash back into the AC lines. As such, I don't think that AC line noise is "over-hyped", but i think that many of the products sold to deal with such a situation are. As i've always tried to stress in many of my posts, you don't always get what you pay for and brand names in many ( if not most ) cases mean very little when it comes to "tweaks".

Just as Marty stated, most of the "brand name" ( and quite costly ) products that he tested failed miserably using what is a very basic AC diagnostic tool. This is not to say that EVERYBODY has line noise and there is AC distortion EVERYWHERE, but that some folks should be using devices of this type while others have probably wasted a GREAT deal of money. That is money that could have been spent elsewhere resulting in greater joy and benefits to the end user.

Then again, one would not know how well any product works if they were relying on a review or reviewer to tell them. The fact that most reviewers don't have the tools or knowledge to verify if these "PLC's" and similar items are really working or not should make most folks quite leary about their recommendations. On top of that, who is to say that your AC supply lines are even remotely similar to the conditions that they are using to test such a device ? I would bet TALL cash that many folks have invested hundreds if not thousands of dollars in power line conditioning when two or three hundred dollars could pretty much solve most "basic" problems ( if one actually exists ). After that, you are at the point of diminishing returns.

Having said that, i would HIGHLY recommend that folks interested in AC treatment beg, borrow or steal ( no, on second thought, don't do that ) an Audioprism Line Sniffer. Not only will this device let you know if you have a large amount of noise coming in with your AC, it can verify just how well various PLC's and AC tweaks actually work. I'm not saying that it is an "end all" type of tool, but i am saying that the relatively small ( less than $200 ) investment now may save you a LOT of money later. Even if you don't buy one, you should talk to your dealer and see if they loan or rent these out. You can then investigate your own system and AC lines to see if you really do need a PLC of some type and / or find out if the PLC that you have is actually doing anything for you. You can also use this device to track down and repair / replace / remove devices within the house that generate noise. Like i said, it is well worth the investment if you buy one. If you can borrow one and accomplish what you need to do in a short period of time, that is even better ( because it is cheaper : )

Marty: While you witnessed the levels of efficiency in filtering out noise with various PLC's and AC tweaks, the fact that you could not hear a difference at a dealer's showroom does not mean that such a device is not worth owning or the resulting benefits are not audible. Given the way that most installations are thrown together ( literally ) in most shops, it is quite possible that even a mega-dollar, highly reputable brand name system might be lacking in detail and resolution due to a poor installation. Don't discount the experience and knowledge that you learned from that demo. Take the high points of what was shown to you and see if they "might" apply to your system and / or long term listening goals. Even if such knowledge / experience does not come directly into play right now, that does not mean that it won't come in handy at a later date. As i mentioned above, it would be best if you could find out how the devices that actually worked would benefit your system at your house. There are just too many variables when it comes to different systems in different locations running off of different AC grids, etc... Sean
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Shasta,

I have to disagree on the "overhyped" dirty power issue. I live in a residential suburb - our voltage is constant and reliable, but my sound so significantly improved after I installed a power conditioner I had to do some testing.

I have an old passive "remote volume control" that was made by AR (ungrounded construction, plastic case - real mid-fi). Many years ago (in another home) I used to use it as a passive preamp between my CD player and amp. I recently tried it again and found it unusable when plugged directly into an outlet - there was so much noise on the AC line that my speakers were making terrible noises with no signal sent through the unit.

Once I plugged the unit into the power conditioner, it was silent. My quality hi-fi equipment did not make such noise, as it is all better shielded and regulated, but the conditioner definately made a remarkable difference in the "air" and sound stage. I describe it as though layers of wool were lifted from my speakers.

I'm not saying that everyone has this type of problem - but in my case it was not just "hype". Installing a simple power conditioner (a $250 Monster HTS2100) rescued my $40,000+ audio system! Try one - most stores have a reasonable return policy. You don't have to start with a multi-thousand dollar unit - as with all things audio, the law of diminishing returns hits quickly on such tweaks.