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Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,500 Watt DC load. This has recently been upgraded to accommodate a higher power output.
We test ambient temperatures 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
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DC Output Load Regulation
|
||||||||||
|
Combined DC Load |
+3.3V
|
+5V
|
+12V
|
+5VSB
|
-12V | |||||
|
A
|
V
|
A
|
V
|
A
|
V
|
A
|
V
|
A | V | |
|
500W
|
7.63
|
3.33
|
8.82
|
5.04
|
36.05
|
11.99
|
1.5
|
5.01
|
0.30 | -12.03 |
|
750W
|
12.63
|
3.33
|
14.12
|
5.04
|
52.06
|
11.99
|
2.0
|
5.00
|
0.30 | -12.02 |
|
1000W
|
17.75
|
3.33
|
20.00
|
5.03
|
72.25
|
11.99
|
2.5
|
5.01
|
0.50 | -12.03 |
| 1250W | 18.84 | 3.33 | 24.04 | 5.04 | 90.14 | 11.98 | 3.0 | 5.00 | 0.50 | -12.02 |
|
1500W
|
18.87
|
3.33
|
22.64
|
5.03
|
115.90
|
11.97
|
3.5
|
5.00
|
0.50 | -12.02 |
| 1600W | 10.00 | 3.33 | 10.00 | 5.03 | 125.00 | 11.97 | 3.5 | 5.00 | 0.50 | -12.02 |
| 2000W | 12.00 | 3.33 | 12.00 | 5.04 | 155.00 | 11.96 | 3.0 | 5.00 | 0.50 | -12.02 |
| 2200W | 12.00 | 3.33 | 12.00 | 5.03 | 173.00 | 11.95 | 3.0 | 5.00 | 0.50 | -12.03 |
Even when pushed to its full 2200W capacity, load regulation is impressive. Voltage stability across both the main and auxiliary rails remains tightly controlled, with only minor variation observed.
| Cross Load Testing | +3.3V | +5V | +12V | -12V | +5VSB | |||||
| A | V | A | V | A | V | A | V | A | V | |
| 1600W | 10.0 | 3.32 | 10.0 | 5.02 | 125.00 | 11.98 | 0.5 | -12.03 | 0.35 | 5.01 |
| 240W | 19.0 | 3.32 | 22.0 | 5.00 | 2.5 | 12.00 | 0.2 | -12.01 | 0.50 | 5.02 |
The Seasonic Prime PX-2200 handled our cross load tests without any issues. When hit with 125A, the +12V rail held at 11.98.
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 |
| 500W | 15 | 14 | 25 | 26 |
| 750W | 17 | 15 | 27 | 27 |
| 1000W | 17 | 16 | 29 | 28 |
| 1250W | 18 | 17 | 33 | 30 |
| 1500W | 19 | 17 | 35 | 32 |
| 1600W | 20 | 18 | 37 | 33 |
| 2000W | 21 | 18 | 39 | 35 |
| 2200W | 21 | 19 | 42 | 36 |
Ripple suppression is solid overall, with both the primary and secondary rails remaining within accepted industry limits. While not class-leading, the results are entirely satisfactory.
|
Efficiency (%)
|
|
|
500W
|
92.27
|
|
750W
|
92.94
|
|
1000W
|
94.96
|
|
1250W
|
94.89
|
| 1500W | 94.37 |
| 1600W | 94.11 |
| 2000W | 92.25 |
| 2200W | 91.88 |
These efficiency results are top tier, and almost hit 95% at peak efficiency. At full load the efficiency drops to around 92%.
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 SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) 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 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)
|
|
|
500W
|
<28.0
|
|
750W
|
<28.0
|
|
1000W
|
<28.0
|
|
1250W
|
<28.0
|
| 1500W | 33.7 |
| 1600W | 35.7 |
| 2000W | 41.1 |
| 2200W | 45.8 |
The fan in this unit is superb, but we have never seen it tasked with such a tough job before. At anything up to 1,500 watts it's very quiet, almost inaudible in real world situations. Once you hit a 1900 watt sustained load it becomes clearly audible, rising to almost 46 dBa at full load. Not a situation you would hope to be running on a regular basis mind you!
|
Temperature (c)
|
||
|
Intake
|
Exhaust
|
|
|
500W
|
36
|
39
|
|
750W
|
37
|
42
|
|
1000W
|
42
|
44
|
|
1250W
|
46
|
47
|
|
1500W
|
48
|
52
|
| 1600W | 51 | 56 |
| 2000W | 54 | 57 |
| 2200W | 54 | 60 |
This unit is highly efficient and the temperatures are really class-leading even when the load gets higher.
