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Cougar GX 1050W Power Supply Review

Additional technical assistance: Peter McFarland and Jeremy Price.

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. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 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
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

We are combining +12V output to get the results.

DC Output Load Regulation

Combined

DC Load

+3.3V
+5V
+12V
+5VSB
-12V
A
V
A
V
A
V
A
V
A V
100W
1.55
3.39
1.78
5.08
6.65
12.24
0.50
5.06
0.20
-12.04
250W
3.45
3.37
4.40
5.07
17.17
12.16
1.00
5.05
0.30
-12.06
500W
7.04
3.35
9.11
5.03
34.63
12.09
2.00
5.03
0.50
-12.08
750W
11.02
3.32
13.73
4.98
52.79
11.97
2.50
5.01
0.50
-12.10
1040W
21.13
3.27
20.03
4.95
71.33
11.89
2.50
4.98
0.50
-12.12

This power supply produced solid load regulation across all outputs, even when delivering 1040W. All rails held within 2.2% of the reference voltage, well in excess of the +/-5% threshold.

Cougar GX 1050W
Maximum Load
1130W

We managed to get another 80W from the power supply before the protection circuitry kicked in. We are happy to report a safe shut down verifying that the overcircuit protection is doing its job.

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
885W 2.0 3.32 2.0 5.03 72.0 11.88 0.2 -12.02 0.50 5.03
240W 20.0 3.28 24.0 4.93 2.0 12.15 0.2 -12.07 0.50 4.95

The Cougar GX PSU handled the Cross loading tests very well and we didn’t experience any issues at all. All the voltages remained well within specification.

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 15 15 20 15
250W 15 25 35 20
500W 25 35 50 30
750W 35 45 55 35
1040W 40 50 65 40

Noise suppression is within the rated parameters, but we noticed that the +5V is right at the recommended limit under full load. The +12V output is within specifications, but again is not one of the better results in recent months, peaking at 65 mV under full load.

Efficiency (%)
100W
81.78
250W
89.12
500W
91.56
750W
89.78
1040W
87.69

Efficiency is quite good, although a little lower than we would expect from an 80 Plus Gold Certified product.

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 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 Refridgerator
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
27.9
250W
28.0
500W
29.3
750W
31.4
1040W 33.2

The Cougar GX 1050W power supply is quiet throughout all the power range, becoming audible only in the last 200W of total power output. Stellar results indeed.

Temperature (c)
Intake
Exhaust
100W
35
37
250W
35
41
500W
38
44
750W
43
52
1040W
46
57

The large 140mm fan handles the ambient temperature increases well, right across the full output, rising to an 11c above ambient intake threshold at 100% load.

Maximum load
Efficiency
1130W
85.34

Pushing the PSU above its rated limits generates an efficiency level of around 85.34%. This is not a viable ‘real world’ situation, but its interesting nonetheless.

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