The 2013 El-Cheapo Power Supply Round-up

PowerCase PHKPOW550080MM

As was the case with Bliss, my experience with this brand is limited. The few I have seen were low end Huntkey products. While Huntkey can make a decent power supply, some of their low end products can be somewhat overrated. Let’s see if this is the case with this product.


After peeling the label off, there was a Huntkey label underneath it. More specifically, a Huntkey CP-350 label. That’s a 350W model, not a 550W, so it looks as though Powercase have just stuck a 550W label over a 350W product. Both labels make this out to be a more 12V-heavy design.

 Load Testing

Test 1 (117.05W Load)

Rail Load Voltage Ripple
12V 4.86A 12.16V 35.0mV
5V 4.95A 4.95V 13.0mV
3.3V 10.06A 3.32V 6.0mV
−12V 0A −12.63V 6.2mV
5Vsb 0A 5.06V 30.4mV
AC Power 140.6W
Efficiency 83.25%
Power Factor 0.67


Test 2 (207.1W Load)

Rail Load Voltage Ripple
12V 9.74A 12.18A 55.0mV
5V 9.86A 4.93V 17.0mV
3.3V 10.06A 3.32V 6.0mV
−12V 0.11A −12.62V 19.4mV
5Vsb 1.01A 5.04V 14.0mV
AC Power 241.43W
Efficiency 85.78%
Power Factor 0.66


Test 3 (264.07W Load)

Rail Load Voltage Ripple
12V 14.48A 12.07V 69.4mV
5V 9.94A 4.97V 20.4mV
3.3V 10.06A 3.32V 6.4mV
−12V 0.11A −12.8V 29.2mV
5Vsb 1.01A 5.04V 15.0mV
AC Power 309.31W
Efficiency 85.37%
Power Factor 0.66


Test 4 (320.3W Load)

Rail Load Voltage Ripple
12V 19.2A 12.0V 94.2mV
5V 10.0A 5.0V 26.6mV
3.3V 10.06A 3.32V 7.0mV
−12V 0.11A −13.06V 46.2mV
5Vsb 1.01A 5.04V 17.2mV
AC Power 385.53W
Efficiency 83.08%
Power Factor 0.66


Test 5 (373.23W Load)

Rail Load Voltage Ripple
12V 23.76A 11.88V 107.0mV
5V 10.1A 5.05V 29.4mV
3.3V 10.06A 3.32V 8.0mV
−12V 0.11A −13.29V 52.2mV
5Vsb 1.01A 5.04V 19.0mV
AC Power 469.17W
Efficiency 79.55%
Power Factor 0.67


The voltage regulation was mediocre at best. The 12V rail managed to stay within 0.18V (or 1.5%) of its nominal 12V, but it dropped to 11.88V in test 5, which equates to a drop of 0.3V, or 2.5%. The 5V rail was off by a maximum of 0.07V or 1.4% (Test 2), and climbed up to 5.05V during Test 5, which equates to a 0.12V, or 2.4% variation. The −12V rail was the worst performer – it only managed 10.75% regulation. While this isn’t allowed in ATX specifications, it’s unlikely to be a major problem, given how little use the −12V rail sees these days.

The efficiency was reasonable for a low end product, peaking at just over 85%. The power factor, while high for a product with no PFC, was still fairly poor compared with higher end products. I did ask for 420W for a 6th test, but the switching transistors exploded. This confirms that it is really only a 350W product, and not a 550W.

Rail Test 4 (320.3W) Test 5 (373.23W)
12V  Powercase-Test4-12v  powercase-Test5-12v
5V  Powercase-Test4-5v  powercase-Test5-5v
3.3V  Powercase-Test4-3.3v  powercase-Test5-3.3v
−12V  Powercase-Test4--12v  powercase-Test5--12v
5Vsb  Powercase-Test4-5vsb  powercase-Test5-5vsb


The ripple suppression on the 12V rail was mediocre. While it was still in spec, it did get above 100mV, which is getting close to the maximum. The 5V rail was a little better, but still slightly above half-spec. The other rails, especially the 3.3V rail, all had excellent ripple suppression, staying below half the maximum limit at all times.


powercase-primary (Custom)_powercase-secondary (Custom)

The input filtering contains two X capacitors, one common-mode choke, two Y capacitors and two MOVs. It’s better than nothing, but there should be another choke. The primary capacitors are 470µF parts from Jianghai, a brand I’ve never heard of before, and the bridge rectifier is rated at 4A. Screwed on to the heat sink are two Fairchild FJP13009 switching transistors rated at 12A. These parts can sometimes deliver more than 370W with exceptionally good design, but that was obviously not the case with this power supply. The 5VSB uses a switching IC, like the Bliss ATX-350. Unfortunately, I couldn’t identify its manufacturer or find a datasheet for it.

The 12V rectifier is a Diodes Inc. SBR20A100CT, which is a 20A Schottky rectifier. The 5V rail uses a 30A ST Micro STPS3045CT Schottky rectifier, and the 3.3V rail uses a 20A Jilin Sino Micro HBR2045 Schottky rectifier. While all of these rectifiers are adequate for what the label claims, it is interesting to note that the 12V rail is actually weaker than the 5V, in spite of being rated for more current. The capacitors are branded Fcon, a questionable quality brand which I have only ever known Huntkey to use. The Supervisor IC and PWM controller is a Weltrend WT7520, which only supports Over Voltage and Under Voltage Protections (OVP and UVP).

powercase-fan (Custom)_powercase-internals (Custom)

The fan is made by Yate Loon. Their fans are normally not too bad in terms of reliability. There was some lubricant in the bearing, but a little more could probably have been used. The fan is temperature controlled, but it was only quiet during Test 1. This is probably due to the smallish heat sinks.

Specifications and Conclusions

Real Wattage 370W
OEM Huntkey
PFC None
Price $25 (As Huntkey CP-350)
ATX Connector type 20+4 pin
Worst-case voltage regulation (12v, 5v, 3.3v) 1.5%, 1.4%, 0.6%
Worst-case ripple (12v, 5v, 3.3v) 107.0mV, 29.4mV, 8.0mV
Worst-case efficiency 79.55%
Input filtering Inadequate
CPU Connector ATX12V (4 pin)
PCIe Connectors None
Molex (Peripheral) Connectors 4
FDD Power connectors 1
SATA Power connectors 2


Pros: Quiet, Voltages and ripple stayed in spec

Cons: Can’t deliver labelled 550W (−2), Low quality capacitors (−2), Mediocre 12V ripple suppression (−0.5), Mediocre Voltage regulation (−0.5)

Score: 5/10 (or 7/10 for Huntkey CP-350 version)

Pages: 1 2 3 4 5 6 7 8 9 10 11 12