2017 iMac: pure sine wave UPS required?

Discussion in 'iMac' started by randian, Sep 13, 2017.

  1. randian macrumors 6502a

    Jan 15, 2014
    I know many newer machines (like the Dell XPS Studio) are sensitive to power inputs that aren't pure sine wave or close to it. Is that also the case for the 2017 iMac?
  2. joema2 macrumors 68000


    Sep 3, 2013
    My 2015 iMac 27 would run on a stepped sine wave inverter, but would make a whining sound. I then got a pure sine wave inverter which ran it OK, and which now runs my 2017 iMac 27. I have not tested the 2017 model by forcing the pure sine wave inverter to switch on, nor have I tried the 2017 on a stepped sine wave inverter. However based on my experience with the 2015 model, I'd recommend using a pure sine wave inverter.
  3. xWhiplash macrumors 68000

    Oct 21, 2009
  4. Buerkletucson, Sep 14, 2017
    Last edited: Sep 14, 2017

    Buerkletucson macrumors 6502


    Sep 12, 2015
  5. kschendel macrumors 65816

    Dec 9, 2014
    I think there's a lot of voodoo and superstition involved with UPS's driving computers. My suggestion would be that if you're buying new, you might as well go for pure sine, simply because it's one less thing to think about. If you already have a stepped-sine UPS, just keep it, or give it a try and see what happens. (Any decent modern power supply should not be damaged by stepped-sine; it might whine, or at worst, fail to start up.)
  6. aibo macrumors 6502

    Jan 17, 2008
    Southern California
    No, it's not required. I have a regular CyberPower without pure sine-wave and it's always worked great throughout all my power outages. And before this one I had a non-sine wave model that worked great for over a 8 years.
  7. Buerkletucson macrumors 6502


    Sep 12, 2015
    Seems kind of contradictory doesn't it?

    If your thinking of a UPS for a new +$2K iMac why not spend the few bucks for a sine wave unit?
    You don't need to get as large of unit as I recommended above either......you can get a smaller version Pure Sine wave unit for about $130.

    Have you ever looked at the output with a scope on the average UPS? :eek:

    They can and do introduce noise and can cause issues to a machine......I'd either get a Pure sine wave UPS or go without, before using one of the older stepped output UPSs.
  8. kschendel macrumors 65816

    Dec 9, 2014
    I've never had a problem running my computers on a stepped-sine APC during power outages. The only reason I wasn't more definitive about it is that I don't have the exact machine that the OP does.

    I occasionally see anecdotes about how brand X computer wouldn't work at all on stepped-sine, with brand X often being older Dell (but I don't know if there's a population effect going on there). But, given that we're driving a digital computer, not a stereo preamp, as long as it works I'm not going to worry about output waveforms. You're free to do so, of course.

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7 September 13, 2017