APC by Schneider Electric Smart-UPS SMX - SMX1500RMI2U - Uninterruptible Power Supply 1500VA (Rack/Tower, extended runtime model, Line Interactive, AVR, LCD Panel, 8 Outlets IEC-C13, Shutdown Software)

Easy and very simple set up

At 750VA it copes with no issues with a couple of modestly powered machines and a 4-disk external exclosure. Works well enough with Linux with the following values accessible through stock apcaccess on ubuntu 12.04. The LCD/menu is quite useful too. The only drawback is that this UPS produces a constants hissing/high frequency noise when used under normal conditions. It's not a loud noise but certainly audible making this UPS unsuitable as a deskside UPS.Output from apcaccessAPC : <snip?DATE : 2014-02-04 14:50:53 +0000HOSTNAME : <snip>VERSION : 3.14.10 (13 September 2011) debianUPSNAME : <snip>CABLE : USB CableDRIVER : USB UPS DriverUPSMODE : Stand AloneSTARTTIME: 2014-02-04 09:24:48 +0000MODEL : Smart-UPS X 750STATUS : ONLINEBCHARGE : 100.0 PercentTIMELEFT : 207.7 MinutesMBATTCHG : 5 PercentMINTIMEL : 3 MinutesMAXTIME : 0 SecondsALARMDEL : 30 secondsBATTV : 54.6 VoltsNUMXFERS : 0TONBATT : 0 secondsCUMONBATT: 0 secondsXOFFBATT : N/ASTATFLAG : 0x07000008 Status FlagMANDATE : 2013-07-14SERIALNO : <snip>NOMBATTV : 48.0 VoltsFIRMWARE : UPS 09.1 / ID=20END APC : 2014-02-04 14:50:55 +0000

As a previous reviewer has stated, the 750VA version of the Smart-UPS X series does have an extremely noticeable ticking noise, which changes pitch based on the state of mains power and whether the battery is charging. It's not a fan noise - I believe it's from PCB components.I didn't buy my SMX750I on Amazon, but APC's tech support were very good. They replaced it twice purely because of the ticking noise, which despite being slightly less noisy on subsequent units, it was still annoying. It must have cost them a lot to ship units to & from me - it was done via a Schneider Electric office in France. After a while they presented some options to replace it with a different model - in my case they replaced it with the significantly more expensive SURT1000I.I later purchased a second-hand (but mid-2013 manufacture date) SMX1000I which had no ticking noise at all. So, I believe the ticking noise is inherent specifically to the SMX750I, and if you do need a line interactive UPS then can only really recommend the 1000 version over this 750.However, if you ignore the ticking noise, the product itself is the usual excellent APC build quality, and tech support is excellent if you do ever need it.

My experience is almost identical to that of Kris. This unit emits a continuous sizzling noise, completely overwhelming the noise produced by the PC (ok, i have a very silent one) and the rest of the electronics. I simply could not work with this object near my desk. But APC support rocks. They sent me another unit to try (it was the same), and eventually replaced it with the more expensive SMX1000I at zero cost for me. The SMX1000I is silent as a tombstone, except for some rare, quick starts and stops of the fan. So I would suggest to everybody worried about background noise to forget about the SMX750I and go for the SMX1000I instead.