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Seasonic Connect 750W Power Supply Review: The Solution To Cable Management Problems

Seasonic Connect is the first PSU with a backplane.

Seasonic CONNECT Comprise PRIME
Editor's Choice
(Image: © Seasonic)

Our Verdict

A high-performance power supply combined with a backplane that allows for shorter cables, an easier installation, and increased airflow.

For

  • Unique design and features
  • Full power at 47 degrees Celsius
  • Improved cable management and airflow thanks to the Connect module
  • Straightforward installation
  • High performance
  • Good build quality
  • Compact dimensions (PSU)
  • Large amount of provided connectors
  • 10-year warranty

Against

  • Noisy
  • Not so good EMI performance
  • Lower than 70% efficiency with 2% load
  • Not compatible with the alternative sleep mode
  • Small distance between the 4-pin Molex connectors

The Seasonic Connect is a unique product since it is the first desktop power supply to use backplane, which is not only a cable-hub, but also hosts the DC-DC converters that generate the minor rails. Thanks to the Connect module, installation is easy, and most important of all, the shorter cables increase airflow inside the chassis leading to lower operating temperatures. Currently, there are no similar offerings, not only from the competition but from Seasonic as well. This product is the first of its kind, and we are expecting more Connect models in the near future.

Editor's Note (4/26): Seasonic informed us that will look into the noise and EMI cons that we highlighted in the review. We will update if a solution is found.

It was high-time for a change in the PSU market, where things don't move so fast. Seasonic thought that it would be better, for cable management purposes, if it broke down the PSU into two parts: one is the main power supply generating +12V, -12V and 5VSB and the second part is a cable-hub backplane, which is mounted on the chassis through strong magnets and it is completely hidden behind the mainboard's tray. Those two parts are connected through a thick cable, which transfers the afore-mentioned rails to the Connect module. The latter passes through these three rails to the system, and it also includes two DC-DC converters, which generate the minor rails (5V and 3.3V). By moving the DC-DC converters to the Connect module, you increase efficiency and allow for a better airflow inside the PSU's main body. Now, what about the cooling of the DC-DC converters. Well, modern systems don't heavily utilize those two rails, so the thermal loads remain low. On top of that, Seasonic uses a heat sink that's large enough to do a pretty good job. 

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Product Photos

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If you don't take into account the single cable that connects the PSU to the Connect module, you can state that this is a fully modular PSU with ultra-short cables, thanks to the Connect technology, which takes away the need for long cables. By shortening the cables, you have two significant advantages: lower voltage drops and higher efficiency. The problem is that you add a modular connection, but if you use a short enough main cable to link the PSU to the Connect module with thick wires, this is not a significant issue. 

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Connect Photos

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We are a bit skeptical about the lack of cooling on the DC-DC converters that are installed into the Connect module, but those won't be stressed by the majority of modern systems. Moreover, if there were any reliability issues, Seasonic wouldn't provide a ten-year warranty to this product. Time will tell whether the lack of active cooling in the Connect will be an issue for some users that might load more than the typical minor rails. 

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Installation Photos

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The installation of the Connect module is straightforward, as long as there is enough space behind the mainboard tray, and the case is large enough to accommodate it, which won't be a problem for the majority of midi tower cases. 

With the provided magnets, you can quickly hook up the backplane in any place that allows for all cables to reach the corresponding sockets. It didn't take us long to install the PSU and its backplane into a Phanteks Evolv X case, which offers ample space, but it doesn't have much clearance behind the motherboard's tray. The backplane's height is 21mm, and the clearance in the Evolv X is close to that.

We had to remove both hinged metal cable covers that this case has and several built-in velcro straps to mount the Connect module. The glass panel on this side allows for a nice view of the Connect module.

Specifications

Manufacturer (OEM)Seasonic
Max. DC Output750W
Efficiency80 PLUS Gold, ETA-A (88-91%)
NoiseLAMBDA-S+ (35-40 dB[A])
Modular✓ (With Seasonic Connect)
Intel C6/C7 Power State Support
Operating Temperature (Continuous Full Load)0 - 40°C
Over Voltage Protection
Under Voltage Protection
Over Power Protection
Over Current (+12V) Protection
Over Temperature Protection
Short Circuit Protection
Surge Protection
Inrush Current Protection
Fan Failure Protection
No Load Operation
Cooling135mm Fluid Dynamic Bearing Fan (HA13525H12F-Z)
Semi-Passive Operation✓ (selectable)
Dimensions (W x H x D) 150 x 85 x 140mm
Weight1.61 kg (3.55 lb)
Form FactorATX12V v2.4, EPS 2.92
Warranty10 Years
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Box Photos

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Power Specifications

Rail3.3V5V12V5VSB-12V
Max. PowerAmps20206230.3
Watts100744153.6
Total Max. Power (W)750

Cables & Connectors

Native Cables    
DescriptionCable CountConnector Count (Total)GaugeIn Cable Caps
Main connector 20-pin and 10-pin sense (220mm)1116-24AWGNo
Modular Cables    
DescriptionCable CountConnector Count (Total)GaugeGauge
ATX connector 20+4 pin (210mm)1118AWGNo
4+4 pin EPS12V (240mm)2216AWGNo
6+2 pin PCIe (280mm)2216-18AWGNo
6+2 pin PCIe (320mm)2216-18AWGNo
SATA (300mm+70mm+70mm+70mm)1418AWGNo
SATA (200mm+40mm)1218AWGNo
SATA (120mm+110mm)1218AWGNo
4-pin Molex (450mm+120mm+120mm)1318AWGNo
4-pin Molex to SATA 3.3V Adapter (150mm+150mm)1218AWGNo
AC Power Cord (1380mm) - C13 coupler1118AWG-

The main fixed cable, which connects the PSU with the backplane, looks short at 220mm, but there is no need for a longer cable, even with large chassis. This cable could be modular as well, but Seasonic decided to make it modular for lower voltage drops since, through this cable, the PSU's entire output has to pass through, under full load scenarios. 

The modular cables are short, but this is not a problem since the backplane is close to all parts that feeds with power. The number of connectors is satisfactory, and our only objection is the short distance between the 4-pin Molex connectors, which is an issue for many PSUs nowadays. 

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Cable Photos

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Component Analysis

We strongly encourage you to have 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.

General Data-
Manufacturer (OEM)Seasonic
PCB TypeDouble Sided
Primary Side-
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV, 1x Discharge IC
Inrush ProtectionNTC Thermistor (MF72 5D-20L) & Relay
Bridge Rectifier(s)
2x GBU1508 (800V, 15A @ 100°C)
APFC MOSFETs
2x Infineon IPA50R190CE (550V, 15.7A @ 100°C, 0.19Ohm)
APFC Boost Diode
1x STMicroelectronics STTH8S06D (600V, 8A @ 25°C)
Hold-up Cap(s)
1x Hitachi (400V, 820uF, 2,000h @ 105°C, HU)
Main Switchers
4x Great Power GPT10N50AD (500V, 9.7A, 0.7Ohm)
APFC Controller
Champion CM6500UNX
Resonant ControllerChampion CM6901T6X
Topology
Primary side: Full-Bridge & LLC converter
Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side-
+12V MOSFETs4x Nexperia PSMN2R6-40YS (40V, 100A @ 100°C, 5.3mOhm @ 175°C)
5V & 3.3VDC-DC Converters: 6x Nexperia PSMN4R0-30YLD (30V, 67A @ 100°C, 6.6mOhm @ 150°C)
PWM Controllers: ANPEC APW7159C
Filtering Capacitors

Electrolytic: 7x Nippon Chemi-Con (4-10,000h @ 105°C, KY), 4x Nippon Chemi-Con (105°C, W), 2x Nippon Chemi-Con (1-5,000h @ 105°C, KZE)
Polymer: 28x FPCAP, 6x United Chemi-Con

Supervisor ICWeltrend WT7527V (OCP, OVP, UVP, SCP, PG)
Fan ModelHong Hua HA13525H12F-Z (135mm, 12V, 0.50A, 2,000rpm, Fluid Dynamic Bearing Fan)
5VSB Circuit-
Rectifier1x MCC MBR1045ULPS SBR (45V, 10A @ 90°C)
Standby PWM ControllerExcelliance MOS Corp EM8569
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Overall Photos

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Seasonic mentions in the product's page that a model of its high-end Prime line, the SSR-750GD2, is combined with the Connect module. Nonetheless, this specific Prime model uses a design that is identical to Seasonic's Focus line, with the significant difference being the use of a larger, 135mm, fan. The bulk cap is also larger. 

On the primary side, we meet a full-bridge topology and an LLC resonant converter, for increased efficiency. The main PCB lacks a modular panel and the DC-DC converters that generate the minor rails, so there is lots of space among its components, which allows for increased airflow. The converters mentioned above are on the Connect module.

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Transient filter

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The transient filter has all the necessary components, but it doesn't perform so well, according to the results that we got from the EMC pre-compliance testing. For the inrush and surge protection, Seasonic used an NTC thermistor along with a bypass relay and an MOV. 

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The pair of bridge rectifiers can handle up to 30 Amps of current, so it is quite powerful for a 750W power supply. 

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APFC converter

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The APFC converter uses Infineon FETs and a high capacity bulk, which is provided by  Hitachi. 

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Main FETs and primary transformer

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The main FETs are installed into a full-bridge topology, and as usual, an LLC resonant converter helps in lower the switching losses. 

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12V FETs

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Four Nexperia FETs, installed on the solder side of the main PCB, handle the +12V rails. 

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Filtering caps

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Besides electrolytic caps, which are provided by Chemi-Con, there is also a high number of polymer caps.

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Soldering quality

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The soldering quality is good enough. On this side of the PCB, you will also find the supervisor IC.

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Cooling fan

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The cooling fan measures 135mm across and uses a fluid dynamic bearing.

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Connect Module

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We also took apart the Connect module. Its build quality is good, and there is a heat sink on top of the VRM's, which hosts a thermistor. The latter provides temperature data to the over-temperature protection circuit. 

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  • Phaaze88
    I was curious about this one. Not bad, but there's room for improvement.
    Reply
  • Math Geek
    i missed this one some how before it was released. but i like the idea and do hope we get more and more of these. is a solution to something i never even thought of as a problem, but now can't imagine doing without!!
    Reply
  • Myrmidonas
    An idea better than RGB in my opinion. Implementation can be improved though.
    Reply
  • bit_user
    Thanks for the thorough and comprehensive review, Aris!

    I don't have a problem with their existing modular setup. I have 3 Seasonic modular PSUs (and one semi-modular) and have swapped two of them between machines, on a couple occasions. It was very nice to be able to swap PSUs without having to unplug, reroute, and reconnect the cables from everything - just disconnect them at the PSU end. I also like being able to borrow cables that came with one PSU to use with another.

    With that said, I would use this style of setup under two conditions:
    Actual PSU performance should equal or exceed their conventional models.
    Cable compatibility should be retained with their existing modular PSUs.
    Otherwise, I'll just stick with what's been working just fine for me, as long as they continue to be available.
    Reply