SilverStone Nightjar 500 W Power Supply Review
By Gabriel Torres on November 8, 2011


Introduction

If you want to build a completely quiet PC, picking components that don’t have fans is the way to go. To fill this market niche, SilverStone offers the Nightjar power supply series, with 300 W, 400 W, and 500 W models, the last two with the 80 Plus Bronze certification. The 500 W model is the latest addition to the family, and in this review we will see if it is worthwhile buying it.

We’ve already reviewed the 400 W model, which was manufactured by FSP. The 500 W model, however, is manufactured by Seventeam. Therefore, they are completely different internally.

The power supply has two LEDs on its rear side, one indicating that the power supply is on and another revealing if the over temperature protection (OTP) circuit has kicked in.

SilverStone Nightjar 500 W power supply
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Figure 1: SilverStone Nightjar 500 W power supply

SilverStone Nightjar 500 W power supply
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Figure 2: SilverStone Nightjar 500 W power supply

The SilverStone Nightjar 500 W is 6.3” (160 mm) deep. As already explained, this power supply doesn’t have fans.

This unit doesn’t have a modular cabling system. All cables are protected with nylon sleeves, but they don’t come from inside the unit. This power supply comes with the following cables:

All wires are 18 AWG, which is the minimum recommended gauge.

The cable configuration is fair for a 500 W power supply, with two video card power connectors and six SATA power connectors.

SilverStone Nightjar 500 W power supply
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Figure 3: Cables

Let’s now take an in-depth look inside this power supply.

A Look Inside the SilverStone Nightjar 500 W

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

SilverStone Nightjar 500 W power supply
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Figure 4: Top view

SilverStone Nightjar 500 W power supply
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Figure 5: The main cover/heatsink

SilverStone Nightjar 500 W power supply
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Figure 6: Front quarter view

SilverStone Nightjar 500 W power supply
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Figure 7: Rear quarter view

SilverStone Nightjar 500 W power supply
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Figure 8: The printed circuit board, with thermal pad

SilverStone Nightjar 500 W power supply
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Figure 9: The printed circuit board

Transient Filtering Stage

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil. 

In this stage, the SilverStone Nightjar 500 W power supply comes with all of the recommended components. The AC receptacle is, in fact, a complete transient filter.

SilverStone Nightjar 500 W power supply
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Figure 10: Transient filtering stage (part 1)

SilverStone Nightjar 500 W power supply
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Figure 11: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the SilverStone Nightjar 500 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the SilverStone Nightjar 500 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one GBJ1506 rectifying bridge, which is attached to the same heatsink as the primary transistors. This bridge supports up to 15 A at 100° C, so in theory, you would be able to pull up to 1,725 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 W without burning itself out. Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

SilverStone Nightjar 500 W power supply
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Figure 12: Rectifying bridge

The active PFC circuit uses two SPW20N60C3 MOSFETs, each supporting up to 20.7 A at 25° C or 13.1 A at 100° C in continuous mode (note the difference temperature makes), or 62.1 A at 25° C in pulse mode. These transistors present a 190 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number is, the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

The output of the active PFC circuit is filtered by four 150 µF x 400 V Japanese electrolytic capacitors from Chemi-Con, labeled at 105° C. Since they are connected in parallel, they are the equivalent of a single 600 µF x 400 V capacitor. Splitting a single capacitor into several smaller ones was performed in order to improve thermal dissipation, which is one of the main concerns with fanless power supplies.

The active PFC circuit is controlled by an NCP1653A integrated circuit.

SilverStone Nightjar 500 W power supply
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Figure 13: Active PFC controller

In the switching section, the SilverStone Nightjar 500 W uses a single-transistor forward configuration with an active clamp. An SPW17N80C3 MOSFET is used as the main switching transistor, while an FQPF3N80C is utilized for the active clamp part. The main transistor supports up to 17 A at 25° C or 11 A at 100° C in continuous mode, or 51 A at 25° C in pulse mode, with an RDS(on) of 290 mΩ, while the second transistor supports up to 3 A at 25° C or 1.9 A at 100° C in continuous mode, or 12 A at 25° C in pulse mode, with an RDS(on) of 4.8 Ω (4,800 mΩ).

In Figure 14, the manufacturer added a copper plate between the transistors and the heatsink to increase thermal dissipation.

SilverStone Nightjar 500 W power supply
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Figure 14: The active PFC transistors, main switching transistor, and active clamp transistor

The switching transistors are controlled by an NCP1562B integrated circuit.

SilverStone Nightjar 500 W power supply
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Figure 15: PWM controller

Let’s now take a look at the secondary of this power supply.

Secondary Analysis

The SilverStone Nightjar 500 W uses a synchronous design, meaning the Schottky rectifiers were replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses seven IRFB3307 MOSFETs, each one supporting up to 130 A at 25° C or 91 A at 100° C in continuous mode, or 510 A at 25° C in pulse mode, with a 5 mΩ RDS(on).

Here again, the manufacturer added a copper plate between the transistors and the heatsink in order to increase thermal dissipation. See Figure 16.

SilverStone Nightjar 500 W power supply
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Figure 16: +12 V transistors

As explained, the +5 V and +3.3 V outputs are generated by two smaller DC-DC converters connected to the main +12 V output. Each converter is located on a small daughterboard. Each converter is controlled by an APW7164 integrated circuit and uses three MOSFETs. One of them is an NTD4969N (up to 41 A at 25° C, 29 A at 100° C in continuous mode, 150 A at 25° C in pulse mode, 9 mΩ), but the other two we couldn’t identify, as their markings were removed. Notice how these converters use tantalum (SMD) capacitors.

SilverStone Nightjar 500 W power supply
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Figure 17: One of the DC-DC converters

SilverStone Nightjar 500 W power supply
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Figure 18: One of the DC-DC converters

This power supply uses a WT7505 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections.

SilverStone Nightjar 500 W power supply
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Figure 19: Monitoring circuit

This power supply uses only high-end electrolytic capacitors, since temperature is the main concern when designing fanless power supplies. The secondary uses a combination of Japanese electrolytic capacitors (from Chemi-Con), solid electrolytic capacitors, and tantalum capacitors on the solder side of the printed circuit board.

Power Distribution

Figure 20 shows you the power supply label containing all the power specs.

SilverStone Nightjar 500 W power supply
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Figure 20: Power supply label

This power supply has a single +12 V rail, so there is not much to talk about here.

How much power can this unit really deliver? Let’s find out.

Load Tests

We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.” 

First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

4 A (48 W)

7 A (84 W)

10.5 A (126 W)

14 A (168 W)

17.5 A (210 W)

+12VB

4 A (48 W)

7 A (84 W)

10.5 A (126 W)

14 A (168 W)

17.5 A (210 W)

+5 V

1 A (5 W)

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

+3.3 V

1 A (3.3 W)

2 A (6.6 W)

4 A (13.2 W)

6 A (19.8 W)

8 A (26.4 W)

+5VSB

1 A (5 W)

1 A (5 W)

1.5 A (7.5 W)

2 A (10 W)

2.5 A (12.5 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

103.2 W

194.6 W

295.7 W

395.7 W

495.6 W

% Max Load

20.6%

38.9%

59.1%

79.1%

99.1%

Room Temp.

43.2° C

42.4° C

42.3° C

43.8° C

48.9° C

PSU Temp.

54.4° C

54.4° C

55.5° C

55.8° C

59.8° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Failed at +5VSB

AC Power

127.0 W

227.4 W

340.5 W

458.1 W

578.7 W

Efficiency

81.3%

85.6%

86.8%

86.4%

85.6%

AC Voltage

117.5 V

117.2 V

116.0 V

114.2 V

112.9 V

Power Factor

0.986

0.992

0.995

0.996

0.997

Final Result

Pass

Pass

Pass

Pass

Pass

The SilverStone Nightjar 500 W can really deliver its labeled wattage at high temperatures.

Efficiency was amazing, always above 85% except on test one, when we saw efficiency at 81.3%, below the 82% mark promised by the 80 Plus Bronze certification. As we always explain, the 80 Plus tests are conducted at a room temperature of 23° C. We test power supplies between 45° C and 50° C, and efficiency drops with higher temperature. Interestingly, this unit officially received the 80 Plus Silver certification, but SilverStone decided to downgrade it to the Bronze level.

Voltages were closer to their nominal values (3% regulation) during all tests, except for the +3.3 V output during tests four and five. It was outside of this tighter range, but still inside the allowed margin at +3.19 V and +3.16 V, respectively. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The SilverStone Nightjar 500 W provided ripple and noise levels inside specifications, but during test five, the +5VSB output presented a noise and ripple level above the maximum allowed. At the +12 V output, it presented a very high noise and ripple level, although still inside the proper range.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

34.0 mV

52.6 mV

69.8 mV

84.6 mV

109.6 mV

+12VB

32.2 mV

48.4 mV

63.6 mV

75.2 mV

104.3 mV

+5 V

13.2 mV

16.2 mV

21.2 mV

25.4 mV

31.2 mV

+3.3 V

15.2 mV

18.6 mV

25.4 mV

27.8 mV

35.2 mV

+5VSB

23.2 mV

26.2 mV

31.4 mV

38.2 mV

55.2 mV

-12 V

17.2 mV

18.4 mV

23.4 mV

27.8 mV

31.6 mV

Below you can see the waveforms of the outputs during test five.

SilverStone Nightjar 500 W power supply
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Figure 21: +12VA input from load tester during test five at 495.6 W (109.6 mV)

SilverStone Nightjar 500 W power supply
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Figure 22: +12VB input from load tester during test five at 495.6 W (104.3 mV)

SilverStone Nightjar 500 W power supply
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Figure 23: +5V rail during test five at 495.6 W (31.2 mV)

SilverStone Nightjar 500 W power supply
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Figure 24: +3.3 V rail during test five at 495.6 W (35.2 mV)

Let’s see if we can pull more than 500 W from this unit.

Overload Tests

Below you can see the maximum we could pull from this power supply with noise and ripple levels at +12 V below the 120 mV limit. During this test, voltages were still within 3% of their nominal values, except on the +3.3 V output, which was at +3.14 V and still inside the proper range. The noise and ripple level at +5VSB was way above the maximum allowed: 72.8 mV.

Input

Overload Test

+12VA

20 A (240 W)

+12VB

20 A (240 W)

+5 V

10 A (50 W)

+3.3 V

10 A (33 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

570.9 W

% Max Load

114.2%

Room Temp.

45.3° C

PSU Temp.

60.0° C

AC Power

678 W

Efficiency

84.2%

AC Voltage

112.2 V

Power Factor

0.997

Main Specifications

The main specifications for the SilverStone Nightjar 500 W power supply include:

* Researched at Newegg.com on the day we published this review.

Conclusions

There is both good and bad news about the SilverStone Nightjar 500 W. On the good side, we have very high efficiency, above 85% most of the time, excellent voltage regulation (3% tolerance) most of the time, and the use of very high-end components, especially capacitors. Also, although officially this power supply has received the 80 Plus Silver certification, the manufacturer downgraded it to 80 Plus Bronze. It is always good to see a manufacturer that is honest with its consumers.

However, the Nightjar 500 W isn’t a flawless power supply. Efficiency at 20% load (100 W) dropped below the 82% mark, which is a major concern, as fanless power supplies are targeted to home theater PCs (HTPCs) and similar applications, where it is quite common to have the computer running at low power. On the other hand, we tested this unit at very high temperatures (which is our normal procedure), and efficiency drops with higher temperature. Also, even though this unit uses very high-end capacitors, noise and ripple levels were very high, with the noise and ripple levels at the +5VSB output going out of the appropriate range when the power supply was delivering 500 W.

The main problem with this unit is its price, USD 200. We know that it is expensive to design and build a fanless power supply, especially when you use only high-end components and opt for a more expensive design. At this price, we expected this unit to be flawless (this is the minimum we expect to see on a power supply to consider it “flawless”: three percent voltage regulation, noise and ripple levels at half of the maximum allowed or less, and high efficiency in all load patterns at high temperatures), which, unfortunately, isn’t the case.

Originally at http://www.hardwaresecrets.com/article/SilverStone-Nightjar-500-W-Power-Supply-Review/1421


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