PC Power & Cooling Silencer 760 W Power Supply Review
By Gabriel Torres on March 16, 2011


Introduction

Hardware Secrets Golden Award

The PC Power & Cooling Silencer 760 W is a relabeled Seasonic S12D 750 W unit, but with a rear 80 mm fan instead of using 120 mm model and a single +12 V rail instead of two +12 V rails. Its highlights include the use of a DC-DC design, 80 Plus Silver certification, and 836 W peak wattage. Let’s check it out.

PC Power & Cooling Silencer 760 W power supply
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Figure 1: PC Power & Cooling Silencer 760 W power supply

PC Power & Cooling Silencer 760 W power supply
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Figure 2: PC Power & Cooling Silencer 760 W power supply

The PC Power & Cooling Silencer 760 W is 7.1” (180 mm) deep, with a 80 mm ball bearing fan (ADDA AD0812UB-A71GL, 3,900 rpm, 50 cfm, 41 dBA) on its rear panel.

Following PC Power & Cooling’s tradition, the Silencer 760 W doesn’t have a modular cabling system. All cables are protected with nylon sleeves and the unit comes with the following cables:

The cables with SATA and peripheral power connectors use 18 AWG wires, but the main motherboard cable, the EPS12V/ATX12V cables and the video card cables use thicker 16 AWG wires, which is always nice to see.

The cable configuration is perfect for a 760 W unit.

PC Power & Cooling Silencer 760 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 PC Power & Cooling Silencer 760 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.

This page will be an overview, and then in the following pages we will discuss in detail the quality and ratings of the components used. This power supply is internally identical to the Seasonic S12D 750 W and Seasonic M12D 750 W units.

PC Power & Cooling Silencer 760 W power supply
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Figure 4: Top view

PC Power & Cooling Silencer 760 W power supply
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Figure 5: Front quarter view

PC Power & Cooling Silencer 760 W power supply
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Figure 6: Rear quarter view

PC Power & Cooling Silencer 760 W power supply
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Figure 7: 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. 

The transient filtering stage of the PC Power & Cooling Silencer 760 W is impeccable, with two ferrite coils and one X capacitor more than the minimum required.

PC Power & Cooling Silencer 760 W power supply
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Figure 8: Transient filtering stage (part 1)

PC Power & Cooling Silencer 760 W power supply
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Figure 9: Transient filtering stage (part 2)

In the next page we will have a more detailed discussion about the components used in the PC Power & Cooling Silencer 760 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the PC Power & Cooling Silencer 760 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

Like the Seasonic S12D 750 W and the Seasonic M12D 750 W (which are internally identical to the Silencer 760 W) this unit has two rectifying bridges feeding two separate active PFC circuits. Each bridge is a GBU806, supporting up to 8 A at 100° C so, in theory, you would be able to pull up to 1,840 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 1,472 W without burning themselves out. Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply. The two bridges are attached to a heatsink.

PC Power & Cooling Silencer 760 W power supply
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Figure 10: Rectifying bridges

As explained, there are two separate active PFC circuits, each one using two FWP12N50C MOSFETs, so we have a total of four transistors. Each one of them is capable of delivering up to 13 A at 25° C or up to 8 A at 100° C (note the difference temperature makes) in continuous mode, or up to 52 A in pulse mode at 25° C. These transistors present a 480 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistors will waste less power and the power supply will achieve a higher efficiency.

PC Power & Cooling Silencer 760 W power supply
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Figure 11: Active PFC transistors

This power supply uses two electrolytic capacitors to filter the output from the active PFC circuit. The use of more than one capacitor here has absolute nothing to do with the “quality” of the power supply, as laypersons may assume (including people without the proper background in electronics doing power supply reviews around the web). Instead of using one big capacitor manufacturers may choose to use two or more smaller components that will give the same total capacitance, in order to better accommodate components on the printed circuit board, as capacitors with lower capacitance are physically smaller than capacitors with higher capacitance. Also, the use of two capacitors in parallel divides the current that flows through each one of them, reducing the amount of heat generated. The Silencer 760 W uses one 390 µF x 420 V and one 330 µF x 420 V capacitors connected in parallel; this is equivalent of one 720 µF x 420 V capacitor. These capacitors are Japanese, from Chemi-Con, and are labeled at 105° C.

In the switching section, two SPP24N60C3 MOSFETs are used, installed in the traditional two-transistor forward configuration. Each transistor supports up to 24.3 A at 25° C or 15.4 A at 100° C (note the difference temperature makes) or 72.9 A in pulse mode at 25° C, presenting an RDS(on) of 160 mΩ.

PC Power & Cooling Silencer 760 W power supply
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Figure 12: Switching transistors and active PFC transistors

The primary is managed by a CM6802 active PFC/PWM combo controller.

PC Power & Cooling Silencer 760 W power supply
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Figure 13: Active PFC/PWM controller

Now let's take a look at the secondary of this power supply.

Secondary Analysis

This power supply uses a DC-DC design in its secondary, meaning that this unit is basically a +12 V power supply, with the +5 V and +3.3 V outputs being generated by two smaller power supplies attached to the +12 V output.

The +12 V output is rectified by eight SBR40S45CT Schottky rectifiers, each one supporting up to 40 A (20 A per internal diode at 110° C, 0.55 V maximum voltage drop). Three are used for the direct rectification and five are used on the “freewheeling” part of the rectification. This gives a maximum theoretical current of 171 A or 2,057 W for the +12 V rail.

PC Power & Cooling Silencer 760 W power supply
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Figure 14: Five of the eight +12 V rectifiers

As already explained, the +5 V and +3.3 V outputs are obtained through two smaller switch-mode power supplies connected to the +12 V output. They are both located on the same daughterboard, which makes use of two APW7073 PWM controllers and seven APM2556N MOSFETs, with a maximum RDS(on) of only 7.2 mΩ.

PC Power & Cooling Silencer 760 W power supply
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Figure 15: The DC-DC converter

PC Power & Cooling Silencer 760 W power supply
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Figure 16: The DC-DC converter

The secondary is monitored by a PS223 integrated circuit. This chip supports OCP (over current protection), over voltage protection (OVP), under voltage protection (UVP) and over temperature protection (OTP). This circuit has four OCP channels (+3.3 V, +5 V and two +12 V), but the manufacturer decided to use only one for the +12 V output, making this power supply a single-rail unit.

PC Power & Cooling Silencer 760 W power supply
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Figure 17: Monitoring circuit

Electrolytic capacitors found in the secondary are also Japanese, from Chemi-Con.

Power Distribution

In Figure 18, you can see the power supply label containing all the power specs.

PC Power & Cooling Silencer 760 W power supply
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Figure 18: Power supply label

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

Let’s now see if this power supply can really deliver 760 W.

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 our tests, both were connected to the power supply single +12 V rail (the EPS12V connector was installed on the +12VB input of our load tester).

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

5 A (60 W)

11 A (132 W)

16 A (192 W)

22 A (264 W)

27.5 A (330 W)

+12VB

5 A (60 W)

10 A (120 W)

16 A (192 W)

21 A (252 W)

27 A (324 W)

+5V

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

10 A (50 W)

+3.3 V

2 A (6.6 W)

4 A (13.2 W)

6 A (19.8 W)

8 A (26.4 W)

10 A (33 W)

+5VSB

1 A (5 W)

1.5 A (7.5 W)

2 A (10 W)

2.5 A (12.5 W)

3 A (15 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

149.7 W

302.2 W

417.6 W

603.9 W

758.4 W

% Max Load

19.7%

39.8%

54.9%

79.5%

99.8%

Room Temp.

44.8° C

43.9° C

44.9° C

47.9° C

45.6° C

PSU Temp.

46.3° C

45.9° C

46.2° C

47.6° C

48.3° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

175.4 W

344.3 W

478.6 W

704.0 W

893.0 W

Efficiency

85.3%

87.8%

87.3%

85.8%

84.9%

AC Voltage

119.2 V

117.6 V

116.4 V

114.6 V

111.2 V

Power Factor

0.980

0.984

0.988

0.992

0.993

Final Result

Pass

Pass

Pass

Pass

Pass

The PC Power & Cooling Silencer 760 W can really deliver its labeled wattage at high temperatures, passing our tests with flying colors.

Efficiency was very high, between 85.3% and 87.8%, just 0.2 points below what is claimed by the 80 Plus Silver certification – keep in mind that the 80 Plus tests are conducted at 23° C and we tested this particular unit between 43.9° C and 47.9° C, and efficiency drops with temperature.

Voltage regulation was another highlight of this product, with all voltages within 3% of their nominal values. The ATX12V specification allows voltages to be up to 5% from their nominal values (10% for the -12 V output). Therefore this power supply presents its voltages closer to their nominal values than necessary.

Noise and ripple levels were always extremely low. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for the +12 V and -12 V outputs, and 50 mV for the +5 V, +3.3 V, and +5VSB outputs. All values are peak-to-peak figures.

PC Power & Cooling Silencer 760 W power supply
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Figure 19: +12VA input from load tester during test five at 758.4 W (24.4 mV)

PC Power & Cooling Silencer 760 W power supply
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Figure 20: +12VB input from load tester during test five at 758.4 W (21.2 mV)

PC Power & Cooling Silencer 760 W power supply
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Figure 21: +5V rail during test five at 758.4 W (7.2 mV)

PC Power & Cooling Silencer 760 W power supply
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Figure 22: +3.3 V rail during test five at 758.4 W (8.4 mV)

Let’s see if we can pull even more from the PC Power & Cooling Silencer 760 W.

Overload Tests

Below you can see the maximum we could pull from this power supply. If we tried to pull more the unit would shut down, showing that its protections were working well. During this extreme condition noise and ripple levels were still inside the allowed range, and voltages were still within 3% of their nominal values.

Input

Overload Test

+12VA

33 A (396 W)

+12VB

33 A (396 W)

+5V

14 A (70 W)

+3.3 V

14 A (46.2 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

929.4 W

% Max Load

122.3%

Room Temp.

45.9° C

PSU Temp.

47.1° C

AC Power

1,129 W

Efficiency

82.3%

AC Voltage

108.9 V

Power Factor

0.994

Main Specifications

The specs of the PC Power & Cooling Silencer 760 W include:

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

Conclusions

PC Power & Cooling hit bull’s eye with the new Silencer 760 W. Being internally identical to the Seasonic S12D 750 W and M12D 750 W units, it carries the same outstanding performance as the original models: efficiency between 84.9% and 87.8%, voltages within 3% of their nominal values and ultra-low noise and ripple levels. The cable configuration is perfect for a 760 W product.

The great news is that this power supply comes at a terrific price (USD 130), significantly lower than the S12D’s when it was still being sold (USD 160).

Originally at http://www.hardwaresecrets.com/article/PC-Power-and-Cooling-Silencer-760-W-Power-Supply-Review/1222


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