The 2014 El-Cheapo Power Supply Roundup

Contents

Tsunami K P4-500W

First Look

These “K” Branded power supplies are commonly bundled with cheaper “Tsunami” branded cases in Australia. Let’s see whether they are OK in a budget PC for a few years, or should be tossed out and replaced when using such a case for a new PC build.

I’m really getting sick and tired of 5V heavy designs still showing up on the market. For crying out loud, how many of us are still using Pentium III and Athlon XP machines these days? The power supply itself is the usual plain grey colour and has decent honeycomb ventilation on the front of the case.

Test Results

Test 1 (75.36W Load)

Rail	Load	Voltage	Ripple
12V	2.41A	12.2V	51.8mV
5V	5.06A	5.06V	49.4mV
3.3V	4.93A	3.35V	34.0mV
−12V	0.1A	−11.8V	31.8mV
5V_SB	0.52A	5.19V	12.8mV
AC Power	102.7W
Efficiency	73.38%
Power Factor	0.6
Intake Temp	26°C
Exhaust Temp	29°C

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Test 2 (103.31W Load)

Rail	Load	Voltage	Ripple
12V	4.75A	12.07V	59.4mV
5V	5.07A	5.07V	49.8mV
3.3V	4.91A	3.34V	33.2mV
−12V	0.1A	−11.94V	37.0mV
5V_SB	0.52A	5.18V	14.2mV
AC Power	136.1W
Efficiency	75.91%
Power Factor	0.59
Intake Temp	26°C
Exhaust Temp	30°C

Test 3 (154.52W Load)

Rail	Load	Voltage	Ripple
12V	9.18A	11.82V	74.0mV
5V	5.09A	5.09V	49.2mV
3.3V	4.88A	3.32V	33.0mV
−12V	0.1A	−12.15V	52.4mV
5V_SB	0.52A	5.16V	18.2mV
AC Power	201.3W
Efficiency	76.76%
Power Factor	0.61
Intake Temp	27°C
Exhaust Temp	32°C

Test 4 (199.84W Load)

Rail	Load	Voltage	Ripple
12V	9.33A	11.8V	91.4mV
5V	9.88A	4.94V	67.6mV
3.3V	9.91A	3.27V	52.2mV
−12V	0.11A	−12.6V	64.4mV
5V_SB	1.02A	5.08V	23.8mV
AC Power	261.2W
Efficiency	76.51%
Power Factor	0.62
Intake Temp	27°C
Exhaust Temp	34°C

Test 5 (247.24W Load)

Rail	Load	Voltage	Ripple
12V	13.57A	11.77V	101.2mV
5V	9.9A	4.95V	66.6mV
3.3V	9.85A	3.25V	51.4mV
−12V	0.11A	−12.92V	87.6mV
5V_SB	1.01A	5.06V	26.2mV
AC Power	331.5W
Efficiency	74.58%
Power Factor	0.62
Intake Temp	27°C
Exhaust Temp	37°C

The 12V rail was at 12.2V in Test 1 and 11.77V in Test 5, which gives us 0.23V (1.91%) worst-case regulation and a drop of 0.43V, or 3.58%. The 5V rail had maximum and minimum values of 5.09V (Test 3) and 4.94V (Test 4), which gives us 0.09V (1.8%) worst-case regulation, and 0.15V, or 3% variation. On the 3.3V rail, we had 3.35V in Test 1, and 3.25V in Test 5, which equates to 0.05V (1.5%) worst-case regulation, and a 0.1V or 3% variation. On average, that gives us 1.74% worst-case regulation, and 3.19% variation. This result is passable, but not spectacular.

The efficiency peaked in Test 3 at only 76.76% – an appalling result by today’s standards, especially with a 230V input. The exhaust air temperature started out at 3°C higher than the intake, and it steadily climbed to 10° higher in Test 5. This is somewhat warmer than usual for this power level, but is to be expected when the power supply is as inefficient as this one. A more serious problem, though is that the 500W rating is a lie. The power supply failed when we attempted to load it to 300W. There were no fireworks, though. Just a burned out and shorted 12V rectifier.

Rail	Test 4 (199.84W)	Test 5 (247.24W)
12V
5V
3.3V
−12V
5V_SB

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The ripple was poorly suppressed, with the 5V and 3.3V rails both exceeding the maximum allowed levels when loaded to 10A.

Disassembly

The input filtering starts at the AC inlet, with an X capacitor and a common-mode choke soldered there. The main PCB adds another two X caps, a common-mode choke and two Y caps, bringing the total component count to three X caps, two common-mode chokes and two Y caps, which is enough components. In place of a bridge rectifier, there are four 2A diodes – quite insufficient for a 500W product, even at 230V. The primary side capacitors are branded HEC and are only 330µF – again, not enough for a 550W product. The two switching transistors are 8A 13007s. It’s a rare event that I can pull more than 300W without blowing 8A transistors up, so like the other parts on the primary side, they are not suitable for a 500W product. The 5V_SB circuit uses a two-transistor design, with a Shenzhen SY Semiconductor E3150 MOSFET as the main switching transistor, and a C945 control transistor. Unfortunately, the critical capacitor is a BH branded part – not one of the few high quality Japanese manufacturers. When it fails, it can cause the 5V_SB voltage to go much higher than normal and fry the motherboard.

The 12V rectifier is a MOSPEC F12C20C – a fast recovery rectifier rated at just 12A – quite underpowered considering that the 12V rail is supposed to be capable of 16A. The other two rails use MOSPEC S20C45C rectifiers, which are rated at 20A. The capacitors are a grab-bag of parts from obscure manufacturers, which is a concern for the long-term reliability of this product.

The fan is branded made by Dong Guan Chaolong. It is a sleeve bearing part, with hardly any lubricant in the bearing. It is not temperature controlled, and is fairly noisy. The heatsinks are extremely thin and easily bent. Heatsinks this thin do not conduct heat away from the semiconductors and up to the fins very effectively.

Specifications and Conclusions

Real Wattage	150W
OEM	Unknown
PFC	None
Price	Unknown
ATX Connector type	20+4 pin
Worst-case voltage regulation (12v, 5v, 3.3v)	1.9%, 1.8%, 1.5%
Worst-case ripple (12v, 5v, 3.3v)	101.2mV, 67.6mV, 52.2mV
Worst-case efficiency	73.38%
Input filtering	Adequate
CPU Connector	ATX12V (4 pin)
PCIe Connectors	None
Molex (Peripheral) Connectors	2
FDD Power connectors	1
SATA Power connectors	4

Pros: None

Cons: Can’t deliver labelled rating (−2), Low quality capacitors (−2), Poor ripple suppression (−2), Mediocre voltage regulation (−1), Low quality fan (−1), Very inefficient (−1), Loud (−1), 5V-heavy

Score: 0/10

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