Power Conditioners

APC S20 Power Conditioner with Battery Backup



  • Pure sinewave battery backup
  • Boost and Trim Automatic Voltage Regulation
  • Power conditioning (AVR
  • Network manageable
  • Serial Connectivity: RS-232
  • Sequenced turn on/off

  • Input
  • Nominal Input Voltage: 120V
  • Input Frequency: 50/60 Hz +/- 3 Hz (auto sensing)
  • Cord Length: 10 feet (3.05 meters)
  • Input voltage range for main operations: 90 - 140V
  • Maximum Input Current: 12A

  • Output
  • Output Power Capacity: 1250 Watts / 1500 VA
  • Nominal Output Voltage: 120V
  • Efficiency at Full Load: 90.00%
  • Output Voltage Distortion: Less than 5% at full load
  • Output Frequency (sync to mains): 47 - 63 Hz
  • Waveform Type: Sine wave
  • Output Connections: (12) NEMA 5-15R
  • Surge energy rating: 4080 Joules

  • Filtering
  • Full time multi-pole noise filtering : 5% IEEE surge let-through : zero clamping response time : meets UL 1449
  • RJ-11 Phone/Modem/Fax protection (four wire dual line), Co-axial Video Cable protection

  • Physical
  • Maximum Height: 5.25 inches (133 mm)
  • Maximum Width: 17.00 inches (432 mm)
  • Maximum depth: 19.00 inches (483 mm)
  • Net Weight 62.00 lbs. (28.18 kg)
  • Regulatory Approvals: CSA,FCC Part 15 Class B,UL 1778
  • Standard Warranty: 2 years repair or replace
  • Equipment protection policy: Unlimited Lifetime
  • MSRP (USA): $1995.00

American Power Conversion (APC)


When I was asked to review the APC S20, a power conditioner with battery backup, I didn’t fully appreciate how important or perfect this unit would be in controlling and protecting the gear in our Home Theater, but after using it for a few months, I now consider the APC S20 an essential part of our setup.

APC describes the S20 and its sibling the S15 as “A single component that eliminates all power threats to your high performance AV system.” The APC S Type Power Conditioners feature in a single unit: surge protection, isolated noise filtering, voltage regulation, power on/off sequencing, remote on/off of four banks of outlets, protection for phone and antenna signals, coupled with pure sine-wave battery backup.

While it is the S20 that is being reviewed I have also include information about the S15 as it is very similar to the S20 in capability, but may be easier to integrate into your AV system depending on the type of remote control used.

Front Panel Controls

Overall I like the styling of the black S20 with its lighter colored metal accents. It goes very well with the rest of my components that are a mixture of black and brushed aluminum.

The front panel of the S20 has a master on/off button, four buttons for navigating the menu system, changing values and displays, and eight LEDs indicating the status of the unit, e.g. on “Battery”, Line OK, Voltage Regulation, Filtering, Overload and the on/off status of two of the AC outlet banks. A two line vacuum fluorescent display allows display of the menu system and monitoring of the system status. Both the LEDs and the display can be dimmed or turned off using the menu system.

Rear Panel Inputs and Outlets

The APC S20 has 12 AC outlets arranged in 4 banks. All outlets include surge suppression, battery backup, voltage regulation and device specific line filtering. (More on the functions of these various banks below.) The APC S Type Power Conditioners also offer surge protection for two pair of coax cables and a telephone line splitter.

The back panel also has a connection for an external battery to increase battery backup time if desired, as well as an Ethernet port, an environmental probe port, an RS-232 port, a USB port, a cooling fan, a circuit breaker, and a wiring fault indicator.

The AC input to the S20 is via an impressive 1/2 inch diameter10-foot power cord.


Now that we have the basics out of the way, let us continue this review by admitting the need for power conditioning, line noise filtering, high-end power cables, things AC etc., are one of the more controversial topics in high-end AV. I believe is lots of copper in power cords, and there is no doubt that the power coming out of the wall is not a pure 60 (50) Hz sine wave, but also contains various harmonics, noise, spikes, surges, brownouts or sags(low voltage), etc.

Fortunately, our AV components do not use this AC line voltage directly, but rather use internal power supplies to convert the AC power from the utility to the DC voltages needed for various amplification, processing or control stages inside the AV component. In the process of conversion from AC to DC, spikes, noise and harmonics are, to a large extent, removed. More expensive AV components typically have larger more expensive power supply components and these typically will do a better job of cleaning up the dirty AC power as well as providing some reserve power to meet short terms peak power needs.

So as long as your AV system is based on reasonably good components, adding a high end power conditioner to the system probably will not lead to improvements in the transparency of the sound or more vibrant colors from your TV or projector, etc. The power supply in the components are doing their job and do it well as long as there is enough AC voltage and current available at the power cord. But therein lies the rub. Power today in many parts of the world, rural areas, as well as in major metropolitan areas, is not as dependable as one may wish, and a power conditioner such as the APC S20 can really help protect your AV gear while assuring peak performance.

So let’s look in a little more detail at what one really needs for AC power control and protection in a home theater audio video system and how the S20 addresses these needs. The various things one might want in such a power controller are:

1. Sequenced on/off and remote control of power to various components
2. Battery backup
3. Voltage regulation
4. Surge, spike and over-voltage protection.
5. Line noise filtering
6. Environmental monitoring
7. Communications and control