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Sunday | November 29, 2015
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FSP Zen 400W Fanless PSU

FSP Zen 400W Fanless PSU

On First Page2. The Unit

Product image


FSP (also known as Fortron-Source) are one of the most experienced computer PSU manufacturers on the planet. Even though they usually keep a low profile and aren’t particularly aggressive in the retail market, FSP recently released a very wide range of self-branded retail products. Today we will have a look at one of the most interesting products they released, the Zen 400W Passive PSU.

Passive units are very popular among HTPC enthusiasts who are trying to build capable but entirely silent running computers. We will see if the Zen can deliver performance capable of appeasing HTPC enthusiasts in this review.

Manufacturer’s Features and Specifications

  • Low ripple & noise
  • Over voltage protection
  • Short circuit protection
  • Fanless design (no fan noise)
  • High efficiency 
  • 100% burn-in test
  • MTBF: 100K hours at 25°C
  • Safety:    
    GNF: UL, Nemko, CB, CE, BSMI, FCC, CCC      
    TNF: UL, Nemko, CB, CE, VDE, FCC
Input Specifications
• Voltage:
110-240 VAC
• Frequency:
47 ~ 63 Hz
• Input current:
3.5A / 2A
Output Specifications
• Over-voltage protection:
+5V, +3.3V, +12V1, +12V2
• Over-current protection:
+5V, +3.3V, +12V1, +12V2
• Remote ON/OFF control:
The power supply shall accept a logic collector level which
will disable / enable all output voltage (excluding +5V standby).
• Power good signal:
turn-on delay 100 ms to 500 ms
General Specifications
• Efficiency:
80% mini. (GNF), 85% mini. (TNF)
• Hold-up time:
17 mS mini.
Environmental Specifications
• Operating conditions:
Ambient temperature 0°C~30°C, 5~95% RH
• Storage and
  shipping conditions:
Ambient temperature -20°C~80°C, 5~95% RH


Packaging and Bundle

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Product image

Product image

The Zen is supplied in a sturdy cardboard box with a small window at the front, showing the bottom part of the product. The box is simple but well designed and the most important specifications of the product can be found at the rear. Inside the box you will find a basic manual, an AC power cable, the necessary mounting screws, a few black cable management straps and a sticker with the company logo.

About Author


Stuart Davidson is Senior Editor at HardwareHeaven having joined the site in 2002.