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Today we take a look at another relatively new unit in the Enermax power supply range, the D.F. 12. This little PSU will suit a huge array of chassis designs given its diminutive 122mm length. It is fully modular, 80 Plus Gold rated and incorporates the Enermax Dust Free Rotation tech for ultra cleanliness.
Enermax ship this unit with a 120mm double ball bearing fan. They have partnered up again with OEM RSY, who seem to have a good relationship with the company. We will take a closer look at the internal design when we open the chassis later in the review today.
- The Smallest* ATX 3.1 ATX PSU with only 122mm in depth
- ATX 3.1 & PCIe 5.1 with 600W 12V-2×6 Cable
- Substantial Packaging Saves 28.7% of Packaging
- Up to 235% Power Excursion
- Invest in Longevity with Dust-Free Rotation Tech.
- Fully Modular 80 PLUS® Gold Certified
- Industrial-Grade 100% Japanese Capacitors
- Optimal Semi-Fanless Tech. with 50% Zero-RPM
- Easier for Back-Connect Devices
Enermax have opted for very simple box artwork. Their logo is printed on the inner brown box, while a slip over colour section highlights some key features along with an image of the unit.
The rear of the box highlights the ‘Dust Free Rotation' Tech, along with cable details, and power supply output figures.
Enermax supply a PSU tester, regionalised power cable, mounting screws and some cable combs. There is also a user reference manual supplied.
It's great to see that Enermax didn't cop out and supply black cables with the unit. The cables are of a decent length. All cables are individually sleeved, which means you may very well be using the little combs they supply to increase the attractiveness of the build on show. The 12V 2×6 connector is set for 600W power output (max), which seems a little unnecessary for a unit rated at 850W.
The D.F. 12 is white, with the only colour being the yellowish/gold accent on the side sticker indicating the power output. They also sell this PSU in black, for $10 less.
The fan is hidden behind a grille at the top of the chassis. We will take a closer look at this shortly. Enermax have their logo in the centre section.
The modular bay is laid out over two rows, with all the connectors labelled for ease of use during the build phase.
The other side has the power switch and connector housing along with the DF Switch.
The Enermax ‘Dust Free Rotation' (DFR) function. Basically this fan spins in reverse to expel dust from the insides of the unit when it is first powered up. Enermax call this a ‘self cleaning mode'. While the fan reverses direction on start up, it is difficult to actually test if this would help remove stubborn dust over the years. It's certainly an interesting idea.
The Enermax D.F. 12 850W power supply can deliver 70.8A via the primary +12V rail, and 20A to the +3.3V and +5V rails.
The fan inside is a ZIC ZFB122512M by ZETA Group. As mentioned earlier in the review, this is a double ball bearing fan – they are generally less expensive than fluid dynamic fans and often slightly louder too. Still, I have used plenty of double ball bearing fans for many years as they have good lifespan. A small plastic shroud covers part of the fan, to direct air over specific components underneath.
The PCB in this power supply is tiny, so therefore it's densely populated with components. OEM partner RSY have adopted various daughter-cards to compensate for the tiny physical width of the main board. Two Japanese 105C rated capacitors by Rubycon make up the primary stage – rated 270uF 420V, for a total of 540uF.
The design incorporates a PFC converter with a full bridge topology with a LLC resonant converter. Minor rails are generated via four FETS which regulate the 12V rail, feeding into DC-DC converters. Soldering on the board is very good, with an overall clean design throughout.
Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. We run at 35c in our environment to greater reflect warmer internal chassis conditions.
We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA
We test in a single +12V configuration.
|
DC Output Load Regulation
|
||||||||||
|
Combined DC Load |
+3.3V
|
+5V
|
+12V
|
+5VSB
|
-12V | |||||
|
A
|
V
|
A
|
V
|
A
|
V
|
A
|
V
|
A | V | |
|
85W
|
0.95
|
3.31
|
0.92
|
5.01
|
6.00
|
12.10
|
0.50
|
5.01
|
0.20 | -12.02 |
|
170W
|
1.70
|
3.31
|
1.67
|
5.01
|
12.35
|
12.08
|
1.00
|
5.01
|
0.20 | -12.02 |
|
425W
|
3.00
|
3.31
|
3.05
|
5.01
|
32.20
|
12.07
|
1.50
|
5.01
|
0.30 | -12.01 |
| 640W | 4.05 | 3.31 | 4.05 | 4.99 | 49.00 | 12.07 | 2.00 | 5.01 | 0.30 | -12.01 |
|
850W
|
5.00
|
3.31
|
5.23
|
4.98
|
65.52
|
12.07
|
2.50
|
5.01
|
0.50 | -12.01 |
Load regulation is tight on 12V.
| Enermax Revolution D.F. 12 850W | Maximum Load |
| 912W |
We managed to get the power supply to deliver 912W before it would shut down, delivering around 62W more than rated specifications.
Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.
| Cross Load Testing | +3.3V | +5V | +12V | -12V | +5VSB | |||||
| A | V | A | V | A | V | A | V | A | V | |
| 760W | 1.0 | 3.31 | 1.0 | 5.03 | 60.0 | 12.06 | 0.2 | -12.03 | 0.50 | 5.01 |
| 165W | 15.0 | 3.28 | 18.0 | 4.93 | 2.0 | 12.10 | 0.2 | -12.02 | 0.50 | 5.00 |
The power supply dealt with the demanding cross load test without any major concerns.
We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.
ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.
|
ATX12V Ver 2.2 Noise/Ripple Tolerance
|
|
|
Output
|
Ripple (mV p-p)
|
|
+3.3V
|
50
|
|
+5V
|
50
|
|
+12V1
|
120
|
|
+12V2
|
120
|
|
-12V
|
120
|
|
+5VSB
|
50
|
Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.
| AC Ripple (mV p-p) | ||||
| DC Load | +3.3V | +5V | +12V | 5VSB |
| 100W | 5 | 10 | 10 | 10 |
| 225W | 5 | 10 | 15 | 10 |
| 450W | 10 | 10 | 15 | 10 |
| 675W | 15 | 15 | 20 | 15 |
| 850W | 15 | 15 | 25 | 20 |
Noise suppression is good across +3.3V, +5V and +12V rails. All of these are well within industry rated parameters.
|
Efficiency (%) 240V
|
|
|
100W
|
89.6
|
|
225W
|
92.4
|
|
450W
|
93.4
|
|
675W
|
92.4
|
| 850W | 90.5 |
Efficiency results from this D.F. 12 power supply are very good – peaking at 93.5% between 40% and 60% load.
We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.
Today to test the power supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.
As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.
KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum
|
Noise (dBA)
|
|
|
100W
|
<28.0
|
|
225W
|
31.4
|
|
450W
|
33.6
|
|
675W
|
36.5
|
| 850W | 37.4 |
The fan in this unit does not stay inactive for long, spinning up quickly and clearly audible over 500 Watts load. At full load the fan is easily heard and somewhat intrusive.
|
Temperature (c)
|
||
|
Intake
|
Exhaust
|
|
|
100W
|
37
|
44
|
|
225W
|
38
|
47
|
|
450W
|
39
|
50
|
|
675W
|
43
|
58
|
|
850W
|
45
|
62
|
The unit gets hotter as the load rises, peaking at 62C in our tests. As we mentioned earlier in the review, this is all contained inside a very small chassis. There is always a downside to this, and in this case that is noise and cooling performance.
|
Maximum load
|
Efficiency
|
|
912 watts
|
89.9
|
At 912 Watts, this unit managed to deliver efficiency at 89.9%.
The Enermax Revolution D.F. 12 is a compact power supply, well suited to a variety of chassis, when high power output is a prerequisite. Due to the small physical size the fan is quite aggressive in this supply and temperatures rise a little under higher loads. Nothing to be concerned about, but there are always some downsides when you reduce the physical dimensions.
The noise factor is something to bear in mind however, because if you are building a small system and are focusing on the lowest possible noise levels, then you should look elsewhere. While it is true that many people accept compromises with smaller chassis in regards to noise, I know plenty of people who want a small, very quiet system. I would recommend you look at a fanless PSU, from Seasonic, for example, in that case.
Technically, the unit performs quite well, but it does not really stand out in any key area. The primary 12V rail is strong in our testing, delivering consistent results across the board. Load regulation is pretty good and ripple suppression scores highly across all the rails.
People looking at this power supply will be likely interested in the small size and while we mentioned the noise and cooling downsides because of this, there is no doubt that the Enermax Revolution D.F. 12 850W is one of the smallest, most powerful power supplies on the market. At only 122mm long it really is quite a unique unit in today's market.
Pricing is set at $140 for the black supply, with this white version costing $10 more. Sadly in the United Kingdom we run into the same availability issues that plague Enermax. They sent us a link to Amazon UK (HERE) with a recommended retail price of £129.90 for the black and £146.90 for the white. When we checked before publication, prices showed a staggering £170.09 from a third party seller. We can only hope this will improve over the coming months into the latter half of 2024.
Discuss on our Facebook page HERE.
Pros:
- Strong power delivery.
- Fully modular.
- Great ripple suppression.
- High quality of build.
- Super small physical dimensions.
- Individually sleeved white cables.
- 10 year warranty.
- 12V performance is strong.
- ATX 3.1 and PCIe 5.1 ready.
Cons:
- Can get quite loud under load.
- Poor availability and high prices in UK.
KitGuru says: The Enermax Revolution D.F. 12 850W targets a niche audience of end user, who requires the smallest power supply with high power delivery and who does not mind a little noise. If you can find it at the recommended retail price, it is definitely worth buying.
