DeepCool have been releasing some high grade quality power supplies in 2015 and have earned a solid reputation among the enthusiast user base.They work with a variety of OEM partners, bringing a wide range of supplies to market in various price zones. Today we look at one of the latest power supplies from DeepCool,the DQ750ST –a non modular unit which ships with 80 Plus Gold certification.
DeepCool wants to position the power supplies as Gold, but keep them affordable.The cost-saving sacrifice in this case was to not make the power supplies modular.
Power supplies Deepcool DQST Series has a system of protection OVP, UVP, SCP, OPP.
Packaging & Contents
This time the box artwork has changed. The ‘ST’ series range is highlighted top right on the box, with an artistic image of the PSU taking up most of the front panel.
The rear of the box is more detailed, highlighting many of the buying points.
This side of the box lets us know how many connectors of each type are available for the unit.
The power supply is wrapped in some air tube bubble wrap.
An AC power cable, bag of screws, and a warranty card are also included.
The PSU
The external build quality of Deepcool's DQ750ST power supply is excellent as always -- a good indication the company is serious about the product they are selling.The unit didn’t pass my ‘screwdriver’ test. This involves running the head of a Philips head driver down the side of the chassis with light to medium force. After all, how many times have you accidentally connected with a power supply during a system build?
A large label shown in the photo above presents the brand and model name in detail.
On the opposite side is a specifications table with all the usual certifications and regulatory symbols.
The white fan is visible, and we will look at this closely when we crack the unit open.Meanwhile,four screws secure the cover onto the rest of the power supply case together,where one screw has a warranty seal over it, so you cannot open the power supply without voiding the five year warranty.
One side of the power supply is vented to aid with air flow. At the side is a power connector and plug.
The DeepCool DQ750ST isn’t a modular design.All cables are hardwired into the chassis.The DeepCool DQ750ST has flat ribbon cables.All of the cables are high quality.
The diagram shows the breakdown of cabling with the unit.
The cable lengths are very good on this unit and should pose no issues even in a full tower chassis.
A Look Inside
As always, I opened up our Deepcool DQ750ST 750W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your 5-year warranty, thanks to the warranty seal Deepcool applied over one of the attachment screws. But for the benefit of you,I cracked ours open so you do not need to, haha. There are no user serviceable parts inside. It is also good to know the OEM of the power supply is Channel Well Technology (CWT),a highly reputable manufacturing known for quality products in this category,and manufactures quite a bit of components by themselves. So without wasting your time any further, let's take a closer look at the different internal components.
The DQ750ST power supply is cooled by the Deepcool DF1202512CH-003 120mm FDB Bearing PWM fan with specially designed fan-impeller.
Starting on the primary side,the input filtering starts at the AC input receptacle and it then trails along the edge of the main PCB.
Viking B-2 is just a Class 130 (B) insulation system used on the transformer.
Taking a closer look around the interior we can see that the DQ750ST is kitted out with a single capacitor manufactured by "Elite".The primary capacitor is rated 470uF, 400V @ 85c.While this is more than suitable for an average 750w unit, some manufacturers choose higher rated 105°C capacitors to ensure that even under extreme temperatures, the unit is able to perform reliably.
Just past this, we see the bridge rectifier is sandwiched between it's own heatsink and a heatsink also housing the main switching transistors and the PFC power components.
Contained on this PCB, and found around the main PCB, are a number of solid and standard capacitors.
The wiring is not well bundled without any mesh sleeving to protect the wiring.
Test System
Below we report the instrumentation used in the test phase for DeepCool DQ750ST.
PowerKiller 2.0. Test bench designed for power supplies up to 2185W.
Stingray DS1M12 USB Oscilloscope
PCE-PA 6000 Wattmeter
Range 1W ~ 6kW
Accuracy ± 1.5%
Multimeters
3 x HT81
1 x ABB Metrawatt M2004
1 x Eldes ELD9102
1 x Kyoritsu Kew Model 2001
1 x EDI T053
Scythe Kama Wireless Thermometer
Center 325 sound level meter.
Voltage Regulation
Load regulation is reasonably good, although it fails short of the best i have seen this year.
Cross Load
A decent set of results, although again, i noticed some movement on the +12V rail when hit with 60 AMPS.
AC Ripple
A power supply should deliver a charge of 3.3V, 5V and 12V. When you analyse the actual current with an oscilloscope you will see that this direct current does fluctuate somewhat. If this fluctuation occurs at low frequency, then it is referred to as ripple. At high frequency it is called noise. It's an arbitrary distinction, and in both cases lower is better, and the more stable the power supply is. Especially overclockers wanting to push their system to the limit benefit from a very low ripple.With an oscilloscope I measured the maximum ripple. The Vtt (voltage-top-top) values indicate the difference between the highest recorded voltages. When the 12 V line has a ripple of 50 mVtt it means that it fluctuates between 11.95 and 12.05 V.Values around 50 mVtt are excellent and ensure that you don't need to worry even during extreme overclocking. Values below 75 mVtt are still very good. If a power supply is far above that level, that is a real minus.
The ripple values of the DeepCool DQ750ST are very good with a maximum of 44.6 mVtt.
Efficiency
Power supply efficiency is without a doubt the most talked about quality in recent years. It's the percentage of current that actually reaches the PC components. If components use a total of 400W, a system with an 80 percent efficient PSU uses 400 / 0.80 = 500W. The same PC with a 90 percent efficient PSU only draws 400 / 0.90 = 444W. It can potentially make a difference in your energy bill, but also translates to other areas. The wasted capacity is turned into heat. The more efficient the PSU, the cooler it stays, the less cooling you need, which improves the lifespan of the components.
With an average efficiency of 89.8 percent the DeepCool DQ750ST power supply is in line with other 80 Plus Gold PSUs.
Noise
I measured the amount of noise produced at a distance of 10 cm at two different loads, 120W and 350W. 30 dB(A) is the lowest I was able to measure, and values in this vicinity mean that a PSU is inaudibly silent. Everything below 35 dB(A) is extremely silent, and above this level you will start to hear the power supply. At 40 dB(A) and higher the PSU is clearly audible.
The DeepCool DQ750ST is more silent than average.The 32 dB will be very difficult to hear.
Temperature
The fan maintains good temperatures inside the chassis, and it spins up considerably in the upper part of overall load demand.
Conclusion
The DeepCool DQ750ST make a very good impression, even if it don't stand out in a single area.DeepCool does prove it can make quality 80 Plus Gold power supplies at an affordable price, so if you don't mind that it isn't modular then this is excellent product.The compact physical dimensions will suit a vast array of potential system builds, especially in the high end ‘media center’ category – those people who want a small HD media system to sit beside a TV, but cram it with enough high end hardware to be able to power any modern Direct X 11 game at 1080p.Technically, the DQ750S performs well.While the internal components may be significantly lower quality from its DQ750 Evo counterparts,the unit still performed reasonably well and managed to keep all rails well within ATX specifications even when pushed slightly over 770w load.Load regulation could have been a little better, but ripple suppression and efficiency both rate as excellent.
The DQ750S is an important power supply for DeepCool, because it is powerful enough to handle a reasonably dual GPU SLI or Crossfire system build, and hits the pricing ‘sweet spot’ under 70$.DeepCool DQ750ST carry a warranty period of five years.