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Enermax Revolution X’t II 750W Power Supply Review

Enermax recently released a successor to the Revolution X't line and the new models are made by CWT, featuring 80 PLUS Gold efficiency, Japanese caps and a quality fan. Today, we're testing the ERX750AWT model.

A Look Inside And Component Analysis

Parts Description

Before proceeding with this page, we strongly encourage you to a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss. Our main tools for disassembling PSUs are a Thermaltronics soldering and rework station, and a Hakko 808 desoldering gun.

Primary Side
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV, 1x CAP004DG
Inrush ProtectionNTC Thermistor & Relay
Bridge Rectifier(s)1x GBU15L06 (600V, 15A @ 115 °C)
APFC MOSFETs2x GP28S50G
APFC Boost Diode1x CREE C3D100060A (600V, 10A @ 153 °C)
Hold-up Cap(s)1x Nippon Chemi-Con (400V, 560uF, 2000h @ 105 °C, KMR)
Main Switchers2x Vishay Siliconix SIHF30N60E (650V, 18A @ 100 °C, 0.125 ohm)
APFC ControllerChampion CM6502S & CM03X Green PFC controller
Switching ControllerChampion CM6901
TopologyPrimary side: Half-Bridge & LLC Resonant Converter Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETs6x SG40N01D
5V & 3.3VDC-DC Converters: 2x UBIQ QM3006D (30V, 57A @ 100 °C, 5.5 mohm) 2x UBIQ QM3016D (30V, 68A @ 100 °C, 4 mohm) PWM Controller: APW7159
Filtering CapacitorsElectrolytics: Nippon Chemi-Con (105 °C, KY, KZE) Polymers: Nippon Chemi-Con (Japan), Enesol (Korea)
Supervisor ICSitronix ST9S313-DAG (OVP, UVP, SCP)
Fan ModelEnermax ED142512M-OA (139mm, 12V, 0.45A, Twister Bearing)
5VSB Circuit
Standby PWM ControllerTinySwitch-LT TNY177PN (18W Peak)
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Since Enermax doesn't have a manufacturing line anymore, the company collaborated with CWT for the Revolution family. The ERX750AWT is based on that company's GPS platform, which utilizes an LLC resonant converter for increased efficiency. Enermax spared no expense on the capacitors, arming this PSU with high-quality Japanese electrolytic caps and a mix of Japanese and Korean polymer caps.

On the primary side, the heat sink is quite large. Meanwhile, two small heat sinks are installed on the secondary side, helping to dissipate heat from the +12V FETs. The design is modern but not exactly cutting-edge, so it doesn't compete directly with high-end units like Corsair's RM750x and EVGA's SuperNova 750 G2. We should note that CWT's GPS platform is also used by Thermaltake in the Smart DPS G 650W/750W units with digital interfaces. This is a decent performer, and the use of quality caps is a major advantage. But it's not perfect (more on that shortly).

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The EMI filter starts in the AC receptacle with two Y caps and a single X cap. It continues on the main PCB with two CM chokes, one X and two Y caps, with the latter installed after the bridge rectifier. There is also an MOV that provides protection against spikes and surges coming from the mains network. The transient/EMI filter is complete.

On the PCB's solder side, we spot a Power Integrations CAP004DG discharge IC that blocks current through X cap discharge resistors when AC voltage is connected, and automatically discharges X caps through the corresponding bleeding resistors when AC is disconnected. This IC provides a small efficiency boost.

The single bridge rectifier is bolted on the large primary heat sink. Its model number is GBU15L06 and it can handle enough current to meet the demands of a 750W PSU.

An NTC thermistor protects against large inrush currents, which occur during the PSU's switch-on phase while the APFC's bulk cap charges. A bypass relay is installed right next to it. This relay helps keep the thermistor cool, where its resistance is high enough to prevent large inrush currents.

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In the APFC converter, we find two GP28S50G FETs and a single CREE C3D100060A boost diode. We tried but failed to figure out who manufactures these FETs; if you know anything about this, please leave a comment. The APFC controller is installed on the solder side of the PCB and it is the famous Champion CM6502S, which is used in many Gold- and Platinum-rated PSUs, and even in some Titanium-rated units like the Raidmax Monster RX-700AT. The APFC controller is supported by a CM03X Green PFC controller that restricts power consumption below 0.5W at standby. Finally, the bulk cap comes from Chemi-Con (400V, 560uF each, 2000h @ 105 °C, KMR) and its capacity is low for a 750W PSU; we don't expect to measure a long enough hold-up time.

The main switching FETs are a couple of Vishay Siliconix SIHF30N60Es. They're high-quality FETs strong enough for this unit's needs. However, during our hold-up tests, where we switch the PSU on and off repeatedly while it delivers full power, something went wrong and one of the FETs literally exploded. There was likely something wrong with the first sample Enermax sent us, so we asked for a second one. Still, the product has to lose performance points because of this issue. While it'll likely never face a full load during switch-on in the real world, we still expect review samples to handle this scenario. Rarely do we encounter failures in these tests.

The dark marks on the resonant tank's caps and the small Chemi-Con cap reveal the magnitude of the explosion.

The resonant controller is housed on a small daughterboard. It is a Champion CM6901.

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On the secondary side, the +12V rail is generated by six SG40N01D FETs installed on the PCB's solder side. Again, we were unable to find any details on these FETs.

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The electrolytic filtering caps are provided by Chemi-Con. The large ones belong to the KZE series, while the smaller ones are higher-quality KY models. Besides electrolytic caps, Enermax also deployed a mix of Chemi-Con and Enesol polymer caps for filtering purposes.

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The DC-DC converters responsible for regulating the minor rails use UBIQ FETs, two QM3006D and two QM3016D. Four Enesol polymer caps help filter these rails, and the common PWM controller is an ANPEC APW7159.

The supervisor IC is a Sitronix ST9S313-DAG (OVP, UVP, SCP), which provides a limited set of protection features. In a higher-end PSU like this one, we want to see a more capable supervisor IC with over-temperature protection support. 

The standby PWM controller is a TinySwitch-LT TNY177PN, capable of providing up to 18W of power with a wide voltage input range (given appropriate cooling).

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The modular PCB doesn't host any filtering caps for extra ripple filtering.

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The soldering quality is mediocre, especially on the secondary side where the conductive paths are enhanced by extra layers of solder. Obviously CWT didn't use its best soldering equipment for manufacturing this PSU.

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The cooling fan carries Enermax's logo and uses a twister bearing, which offers a long lifetime to match the high-quality FDB and HDB fans we're more familiar with. Enermax cites a 160,000-hour MTBF for this fan. Its profile is fairly relaxed, so under normal conditions the ERX750AWT is quiet.

Aris Mpitziopoulos
Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.