Originally Posted by gene9p
My sub had to be repaired and so did my cd player..
Not likely due to brownout. Low voltages generally don''t damage electronic equipment. They may not function correctly if the voltage is low enough, but when the voltage returns to normal, they should be fine. More likely due to surge, maybe experienced at the same time. If so, then all you need is surge protection. Or combine it with AVR.
You still haven''t shown a compelling reason to get a UPS. But lets look at UPSs so you can decide what might make sense for your needs.
The starting point is a standby UPS. Your equipment is on line power until the voltage goes below a certain point or drops out completely. Then the UPS disconnects from the line and powers your equipment from battery through an inverter. Output waveforms vary depending on how much you are willing to spend: square wave, stepped square wave, or a close approximation of a sine wave. Equipment with switch mode power supplies will generally run just fine on any of these. Equipment with linear power supplies are generally better off with the latter two wave forms because of transformer heating. BTW there is a short duration when switching to/from battery when the attached equipment receives no power. You don''t notice anyting because this is less than the hold up time of the equipment.
Line interactive UPSs are a standby UPS with an automatic voltage regulation (AVR) circuit added on. Usually the AVR is simply a transformer with multiple taps which are switched in or out to keep the output voltage within a certain percentage of nominal. Like the standby UPS, a line interactive UPS does not switch to battery until line voltage goes below a certain point or drops out all together.
A third type of UPS is the double conversion UPS. The AC line voltage is used only to charge the battery. The battery in turn is always powering the inverter, which in turn powers your equipment. Your gear always sees the same voltage regardless of what is going on with the line.
IMHO all the major brands are pretty good. I would avoid unknown brands for a variety of reasons. Once you have decided on the kind of UPS you need, you need to determine the VA ratihg and run time required, Once you have that, you can go shopping.
FWIW when people praise a UPS for protecting things when other things not on UPS were damaged, it wasn''t necessarily the UPS per se that saved the equipment. It was the MOV surge protection embedded in the UPS for its own protection which protected down stream devices. IOW the UPS functioned as a very expensive surge protective device.
IMHO if you don''t need to run your gear during a power failure, you don''t need a UPS. If your gear is functioning properly during brownouts, you don''t need AVR. But it doesn''t sound like appropriate surge protection is indicated.