Unlike some other commercially available UPS technologies, the double-conversion design completely isolates output power from all input power anomalies and delivers 100-percent conditioned, perfect sine-wave output—regulating both voltage and frequency. Even when presented with the most severe power problems, power output remains stable. Output voltage THD is held within two percent of nominal specification for linear loads, and within five percent for nonlinear loads and  for supporting equipment that is sensitive to a distorted voltage input as a result of harmonic loads. In the event of a utility power failure, there is no delay transferring to backup power.

Aaron Levinson

Sent from my iPhone

> On Jun 19, 2014, at 3:24 PM, Robert Cham <[log in to unmask]> wrote:
> 
> Take a close look at the sine wave distortion of your UPS.  Many are not sine waves at all. Computers may not care, but analog electronics do.
> 
> Responding to another thread, back in the '80s, Straight Wire Audio made a balanced phono preamp. It required rewiring your tonearm, but it was a godsend for radio stations whose studios were in high RF environments.
> 
> Think about it, there are two wires for each channel on a phono pickup.  One channels low is generally grounded.  that;s usually a strap that can be removed.  Then you can feed it into a balanced mic preamp, and all you have to deal with is the RIAA curve.
> 
> Bob Cham
> 
> 
> 
>> Do people ever use dual-conversion online UPS's for the purpose of power-line isolation for audio equipment?
>> 
>> The power is constantly going to the battery and running off the battery being reconverted back to AC.  Thus isolating the equipment from any fluctuations from the power mains.
>> 
>> It's what I use for my computer room servers, and so far (knock on silicon) I haven't lost a power supply yet.
>> 
>> Depending on the size they can produce some heat and noise (from the fans cooling the rectifiers, etc) but if someone's considering rewiring an entire house/studio perhaps an online UPS would work as well for less investment, maybe in a nearby closet, etc.?  Not an electrical engineer