Cougar LX Series 600 W Power Supply

1. Introduction2. Bundle & Cabling3. External4. Internal5. Methodology & Testing6. Closing Thoughts7. View All Pages

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 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
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
60W	0.90	3.33	0.95	5.10	3.90	12.22	0.50	5.02	0.20	-12.04
120W	1.60	3.31	1.62	5.07	8.20	12.15	1.00	5.02	0.20	-12.04
300W	3.00	3.28	3.13	5.00	21.94	12.00	1.50	5.01	0.20	-12.05
450W	4.15	3.24	4.12	4.90	33.55	11.97	2.00	5.01	0.30	-12.06
600W	5.17	3.19	5.33	4.88	45.30	11.82	2.50	5.00	0.30	-12.07

Load regulation is fair, there is quite a bit of fluctuations on all rails as can be seen in the table above. Between 4% and 5% actually which is one of the poorer results we have seen in recent years.

Cougar LX Series 600 W Power Supply	Maximum Load
	612W

We managed to get 612W out of the Cougar LX Series 600 W before it shut down gracefully.

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
590W	1.0	3.33	1.0	5.09	46.0	11.82	0.2	-12.05	0.50	5.03
145W	12.0	3.17	15.0	4.85	2.0	12.19	0.2	-12.01	0.50	5.01

The supply passed the cross load test, although there were noticeable dips on the rails.

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
75W	20	10	10	15
150W	25	15	20	15
300W	25	15	30	20
450W	35	20	35	30
600W	45	25	45	40

Noise suppression rates as acceptable, however we do need to point out the less than stellar +3.3V result at full load, of 45mV – just inside the industry rated tolerance parameters. The +12V rail peaks at 45mV under full load conditions.

These are not the best results we have seen in recent months, but technically the unit has not failed any of the AC Ripple tests above.

Efficiency (%)
75W	82.12
150W	86.12
300W	88.14
450W	87.32
600W	86.19

Efficiency peaks at just over 88 percent at around 300 watt – 320 watt load. This drops down to just over 86% at full 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 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)
75W	<28.0
150W	<28.0
300W	36.7
450W	38.3
600W	41.6

The fan spins slowly when load is below 250 watts, but it spins up very quickly at higher loads, and becomes a little intrusive when the power supply is delivering over 500 watts. Ideally you want to be running this supply at between 200 watts and 400 watts – which actually accommodates many many enthusiast systems today. Yes, believe it or not, very few people need a 1000 watt power supply for their system.

Temperature (c)
	Intake	Exhaust
75W	35	39
150W	35	44
300W	37	51
450W	41	57
600W	44	65

The large fan works hard as load gets higher, but the lowish efficiency levels force fairly high temperatures at full load situations. It is not really very practical to be running this supply at close to 600 watts for extended periods of time anyway.

Maximum load	Efficiency
612W	85.9

At 612W the Cougar LX Series 600 Watt supply drops to 85.9%. This is not a viable ‘real world’ situation, but its interesting nonetheless.

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