External Hard Drives work perfectly fine with 'Pure Sine Wave' UPS, right?

Discussion in 'Mac Accessories' started by doxavita, May 9, 2011.

  1. doxavita macrumors 6502a

    Jul 6, 2010
    I'm thinking of buying a UPS that is 'Pure Sine Wave' Compatible for my iMac. External Hard Drives would work perfectly under such UPS, right?
  2. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
  3. gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N
    They would work as well as other UPSs.

    UPS inverters use a similar frequency [range] to that which is used by the switching DC supply used by the external drive. Both are possible noise sources for their output (AC in the case of the inverter; DC for the HD supply), but are sufficiently filtered (smoothed). I would bet, without seeing actual waveforms from the different UPSs, that either type's noise level is much less than what would have an effect on equipment's power supplies. (If I had the energy, I'd go get my 'scope and take a snapshot of the APC output. In fact, someone out there has probably already done that.)

    I wouldn't worry too much about buying a "Pure Sine Wave" type over other UPSs. I'm running several models of APC UPSs in house, both the smaller "consumer" models and the more "pro" model for my Mac server. The smaller, consumer model, runs my "farm" of five external drives without any problem. I have another one running my sat receiver and its external drive.
  4. doxavita thread starter macrumors 6502a

    Jul 6, 2010
  5. DanielCoffey macrumors 65816


    Nov 15, 2010
    Edinburgh, UK
    Pure Sine Wave is only needed for devices such as the newer iMacs and Mac Pros. Their modern power supplies are fussy with the wave form of the power when the UPS is on battery.

    Read some for and against reviews of the Cyberpower UPS here - http://forums.macrumors.com/showthread.php?t=1024208

    I personally am using an APC SMT1000I for the Mac Pro in my sig and would recommend it as reliable (and cost effective since I traded in my old UPS under the APC TradeUPS programme.
  6. doxavita thread starter macrumors 6502a

    Jul 6, 2010
    Yes, I've read good things about the CP1500PFCLCD. I would be using it with a 27" 2011 iMac and one external hard drive.

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