I plan to move my ARC/ML audio system to Mexico and am researching what I can do about the funky power lines South of the border. I'll share what little I know.
Power "conditioners" can be organized into four general catagories:
1)SURGE SUPPRESSORS: The ones at the bottom of the heap are just plug banks that protect equipment from being damaged by power spikes and surges which routintely occur on AC lines. These are passive devices normally using MOVs, fuses, baluns or some other forms of protective circuitry. Normal AC lines may vary from 90 to about 140 volts with spikes going higher. I am not sure that claims about protecting against lightning strikes are relevant as most better equipment has fuses that would blow in such an event. Some surge supressors can be current limiting, so be careful if you want to plug in a power amp and still have any headroom left for sharp transients!
2)POWER CONDITIONERS (NOISE FILTERS): These units, passively filter out AC line noise, often filtering digital and analog componenets separately. Sometimes they prevent digital noise from your CD, DVD player etc from returning into the AC line. Usually they will filter out EMI, RFI, other forms of noise on the AC line although some filter common mode noise, and some do not. Some line conditioners use chokes that can limit current, and can affect the sound of your equipment. Most "power conditioners" also include surge supression features as well. You can get most top of the line units for under a grand, and adequate units for far less.
3) AC VOLTAGE REGULATORS: The passive units above will do nothing to correct high or low voltage coming from your wall socket. If your wall outlet drops to 90 volts and your system starts sounding like mud, or if you get 140 volts and suddenly have an unwanted cooktop, they can do nothing. However, some line conditioners have a Voltmeter on the front (Monster, Panamax) so you could at least turn off your equipment if the voltage from your wall has become manic or depressive.
Voltage regulators, however, are active units that will take the AC coming out of the wall and maintain the voltage at constant 120 volts +or-. Some units also filter out EMI, RFI, common mode noise, and provide some level of surge protection. Some voltage regulators also correct the AC into a perfectly formed 60 hertz sine wave, and some do not.
Voltage regulation sounds good, but these units can often be big, heavy, hot, noisy (fans or swithes), or expensive. Most are also limited as to how many watts they can pull, and cannot handle a power amp well. They also offer different numbers of outlets, of differing quality, and may not have room for all your components without an added plug bank.
If you want a smaller, lighter weight (30lbs) Voltage Regulator with noise filtration, surge supression, and 8 outlets, take a look at the EP15A from ExactPower which uses a comparator to regulate and correct your AC power. You get a picture perfect 120 volt, 60 hertz sine wave to feed your system! It's a bit pricey, but can be found cheaper used and corrects most of the acute AC problems without current limiting. I am going to try this unit, but have not yet had the opportunity.
4) LINE BALANCERS: These units, like those from BAT and Equi=Tech take in your AC from the wall and output current that is literally balanced. Normal AC has 120 volts on the hot leg, while balanced current has 60 volts on both the hot and neutral leg. The advantage of balanced power is apparently the cancellation of common mode noise. These units may or may not provide voltage regulation and some EMI and RFI filtration, surge supression, etc. You need to read the specs and reviews carefully, because these units can present power limintations and be heavy and expensive.
Again Exact Power makes an SP15A unit that will put out balanced power when used in conjunction with their EP15A mentioned above. But it can get expensive to have it all!
The combinations of features are endless, and the terms can be confusing. I just spent a couple of week on the Internet buggering my brains out over this stuff, and am still sorting out all the claims, terms, and misleading nonsense.
Aside from the electrical engineering, the subject of power conditioning is confusing due to the use of trademarked terms that sometimes misrepresent what the specific power conditioners actually do. For example, Panamax's 5510 AC "Regenerater" has nothing to do with AC regeneration (regenerating the 120 volt AC sine wave from DC) although it seems to be a very good line conditioner. Various "balanced power" units have nothing to do with putting out balanced AC as described above. Be careful when researching and read what the units under consideration actually do and how they do it. I am suspicious of companies like Monster, because their website offers no comprehensive technical specs or indications of what electrical components they are using to filter the AC line. Nevertheless, in all fairness I have used a very convenient Monster power conditioning strip with good results in noise filtering. Sometimes it's difficult to separate the science from the sales hype.
In the end, you need to research and then audition power line conditioners, voltage regulators, and line balancers like you would any other component - for the affect on the sound of your system. If you get serious, this AC equipment will probably cost you as much as another component in your system!
First, I would recommend diagnosing your AC line! Are their current fluctuations, is it noisy, is it properly grounded, phase correct, etc? Take the time to find out. Maybe just a dedicated line or isolated outlet would solve your problems. Don't forget that good audio equipment also has its own power regulation and protective fuses, etc. Above all, if your AC ain't broke, don't fix it, and instead use your money to upgrade the other components in your system.
I would appreciate any advice, especially from an electrical engineer, on what I need to do about the power in Mexico so I can run my gear without fear.