Introduction

We would like to thank Lian Li for supplying the review sample.


Lian Li recently added a strong SFX power supply made by Helly Technology, a lesser-known OEM, to its portfolio. This OEM owns the 1st Player brand I came across in our Steampunk PS-750SP review two years ago. It is always nice to see new players in the field as it offers choice, especially in the SFX market, which is considerably smaller than the ATX PSU market.

It is also impressive to see such a compact PSU delivering 750 W of power, and I would be even more impressed if there wasn't the Cooler Master SFX Gold unit with 850 W maximum power. The performance crown for SFX PSUs currently goes to Corsair's SF750 Platinum, which Great Wall makes, so it is the reference for all PSUs of this form factor.

The SP750 earned the Gold efficiency certification from 80 PLUS and is classified as Platinum in efficiency and Standard+ in noise output on the Cybenetics scale. Keeping noise output low at light and moderate loads is a semi-passive operation, which has the DBB fan remain quiet under less stressful conditions. According to Lian Li, the fan's passive operation lasts up to 40% load, which is not actually the case. Finally, a version of the SP750 without braided sleeving for the cables will be bundled with the O11 Dynamic MINI chassis.

Specifications

Photos

At the face of the box is a photo of the PSU, along with the model and capacity descriptions. Two badges depict the 80 PLUS Gold efficiency certification and five-year warranty. Listed on the back of the box are the PSU's dimensions and list of available connectors.


Protection inside the box is good. The bundle includes a "thank you" note, the user manual, fixing bolts, and all necessary cables.


The cooling fan is not centered, which doesn't look weird because it has the metallic plate with Lian Li's name on it. At the front of the unit is the small power switch next to the AC receptacle.


There is a sticker with the unit's model number on one of two sides; the opposite side has the power specifications label.


The modular panel has nine sockets, two for the 24-pin ATX connector, three for the peripheral cables, and four for the EPS and PCIe cables. As you can see, the connector notches are on the same side for both rows, which makes disconnecting the cables more difficult since you will first have to unplug the cables of the top row. This could be avoided with the notches for the bottom sockets on the opposite side.


The fan grill is not restrictive, which increases airflow. That having been said, to keep noise output low, you also need a relaxed fan-speed profile. The top cover is made out of aluminium and has a brushed finish, which is a nice touch.

Cables and Connectors

The cables are of the proper length for an SFX PSU inside a small chassis, and there are enough connectors, including two EPS and three PCIe ones. My only objection is that both EPS connectors are on the same cable out of 18AWG gauges instead of thicker ones. If these two EPS connectors are heavily utilized, they may damage the single PSU connector, or the gauges. As the modular panel has four 8-pin sockets for the EPS and PCIe cables, using a single EPS cable with two connectors makes no sense since it results in a spare, unused 8-pin socket.


There are plenty of peripheral connectors, and at 120 mm, they are adequately far apart for an SFX PSU. Finally, the peripheral cables are flat and black, while the ATX, EPS, and PCIe cables are individually sleeved.

Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand the insides of a PSU better.



This is a new platform by Helly Technology, or the first time I have come across it. The heatsinks are small on both the primary and secondary sides, and both VRMs and the fan-control circuit are installed on a daughter-board to save space. Airflow will be good since no cables are disrupting it, and the distance between parts is good as well, especially if we take into account the tiny dimensions of the main PCB. Helly used decent parts—the only exception is the Yate Loon fan. I am not that fond of this brand when it comes to fans because they allow tooling to grow too old before replacing it, which results in high production tolerances with units produced with said tooling.


The transient/EMI filter stages have all the necessary parts.


I found a TRX NB210108 SMD-Y-CAP on the business side of the main PCB.


The MOV is not covered in heat shrink, so you will find parts of it everywhere inside the PSU if it blows. Moreover, there is no inrush protection, which is a shame for a product that wants to compete with the high-end offerings in the 750 W SFX category.


The single bridge rectifier is bolted to a small heatsink. Lian Li should ask for a larger heatsink.


The APFC converter uses two Oriental Semiconductor FETs and a Global Power Technology boost diode. The bulk cap is by Chemi-Con and doesn't have enough capacity to provide a hold-up time of over 17 ms.


The APFC controller is a Champion CM6502UHH.


The main FETs are by Oriental Semiconductor and installed in a half-bridge topology.


The LLC resonant controller is a Champion CU6901T2X. The second photo above depicts the resonant tank.


The unit's main transformer is semi-surrounded by a metallic shield also acting as a heatsink.


The FETs regulatimg the +12 V rail are installed on the solder side of the main PCB.


Two DC-DC converters generate the minor rails. They are installed on a daughter-board that also hosts the fan's header.

They use six Infineon FETs, and their joint PWM controller is an Anpec APW7159C. I also found the supervisor IC, a Weltrend WT7527RA, on the same board as the VRMs.


There aren't many electrolytic caps since Helly mostly used polymer ones. That having been said, the few electrolytic caps Helly uses are high-quality Chemi-Con caps from good lines.


The 5VSB circuit uses an EM8569C PWM controller.


The supervisor IC is a Grenergy GR8313, which only provides the essential protection features.


Several polymer caps are installed on the face of the modular PCB.


Soldering quality is decent; not the best I have seen, it is not bad, either.


The cooling fan is by Yate Loon and not of good quality. They should go with a Globe Fan for a double ball bearing, or an FDB by Hong Hua to keep the cost low but still offer a good fan.