Danger - High Voltage!


The readers of AnandTech have waited a long time for us to do real power supply reviews. The waiting has come to an end and we hope you will find the results to be worthwhile. In the near future we will begin publishing power supply reviews on a regular basis, with the goal of providing the detailed analysis and benchmarking results our readers have come to expect.

We know the AnandTech audience expects a high level of professionalism, and it took a while to put together the right equipment in order to provide that for PSU testing. To kick things off, we want to talk about each part of the equipment and how it will help us with the reviews. With a proper understanding of the equipment and testing methodology, we hope you will see what will make the AnandTech power supply reviews so special.

Why It is so Difficult to Test Power Supplies
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  • jtleon - Thursday, July 12, 2007 - link

    For the most accurate sound level testing, the air temperature around the microphone and the power supply is very VERY important. The microphone must reach steady state temperature and be calibrated at that temperature. The air temperature in the anechoic chamber must be maintained as constant, otherwise the microphone measurements will be off as much as 3-4dB in my experience for a temp delta of only 15°F.

    Also, no one is interested in the noise PS generates inside the PC case, rather the noise emitted to the exterior of the PC. And beware the air temperature inside the PC is much much higher than the interior PC air temperature. I don't see how your test approach will address these critical issues.
  • jtleon - Thursday, July 12, 2007 - link

    Ooops...I meant to say,

    And beware the air temperature inside the PC is much much higher than the exterior PC air temperature.
  • LTG - Thursday, July 12, 2007 - link

    This is exactly the high bar I expected from AT and I'm really glad to see you guys do it right.

    I've always felt that other review sites were missing a lot in this area.

    LTG
  • lsman - Thursday, July 12, 2007 - link

    Thanks, looking forward for the reviews. Please don't let it delay (or MIA) like those m-atx or motherboard.
    It will be more interesting than all those HSF reviews...
  • Kensei - Thursday, July 12, 2007 - link

    quote:

    In most parts of the world it is usual to use a grid power of 230VAC with a frequency of 50Hz. In the US, Canada, and parts of South America however the standards are around 117VAC with a frequency of 60Hz (commonly rounded to 120VAC).


    A small nitpick... Japan is also 120VAC (actually 100) and uses flat blade plugs. I live in Japan and everthing I brought here from the US works fine. See
    http://www.kropla.com/electric2.htm
  • Martimus - Thursday, July 12, 2007 - link

    I used to test power sources and signal sources for variaous automotive components, and I am wondering why you are using a multimeter to measure the output instead of an oscilliscope. You can measure both current and voltage and actually capture the waveform to measure the ripple voltage with a good o-scope. When it comes to analyzing signals, the oscilliscope is a far more valuable tool than a multimeter.

    just my 2 cents.
  • acronos - Thursday, July 12, 2007 - link

    I'm interested in how the power supply handles electrical noise from the power company. I know most of us have battery backups, but the power supply should do power line noise suppression too. In my area we have brownouts (low voltage), spikes (lightning strikes nearby), and just general noise. I also use computers in a manufacturing environment, which causes significant noise on the power lines.
  • LoneWolf15 - Thursday, July 12, 2007 - link

    What you want then, are line conditioners, or a UPS with line-conditioning capability.

    The most a power supply provides is Active Power Factor Correction, which will clean up things a little, but that's not a subsitute for a UPS with line conditioning, which will solve your issues with brownouts and spikes. This kind of gear would be expensive and bulky to try and add into a power supply; I don't see it happening any time soon.
  • LoneWolf15 - Thursday, July 12, 2007 - link

    Clarification: Not every PSU has Active PFC --a better explanation can be found here:

    http://www.dansdata.com/gz028.htm">http://www.dansdata.com/gz028.htm
  • sprockkets - Saturday, July 14, 2007 - link

    Yeah very good explanation. Another way of looking at it is I found a site sometime ago that showed the pfc as a 90 triangle to show the relationship.

    I'm looking for a good test of those fanless power supplies, but again, without a fan it does put a damper in the cooling.

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