Verax 300W PSU

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TEST RESULTS

Measurements were made at 4 power levels: 65W, 90W, 150W and full power. The unit was allowed to run for at least 10 minutes at each power level before measurements were taken. The room temperature was 18C.

LOAD
65 (W)
VR
90 (W)
VR
150 (W)
VR
300 (W)
VR
+5V
20
2%
20
2%
40
2%
80
2%
+12V
24
2%
36
2%
60
2%
144
2%
-12V
3.6
2%
3.6
2%
4.8
2%
4.8
2%
+3.3V
13
2%
26.4
2%
39
2%
65
2%
-5V
1
2%
2
2%
2
2%
2
2%
+5VSR
2
2%
2
2%
4
2%
4
2%
AC Power
97W
130
202
406
Efficiency
67.0%
69.2%
74.2%
73.9%
Fan Voltage
7V
11.7V
11.8V
11.8V
Noise (@ 1 cm)
38 dBA
44 dBA
48 dBA
57 dBA
Case Temperature
30C
32C
33C
31C
Power Factor
0.62
0.64
0.67
0.68

VR = Voltage regulation was excellent, dead-on at almost all loads, on all lines. The worst case was a negligible 11.9V for the 12V line at 300W. All others were within 0.1V -- better than 2%.

Efficiency, at 67% to 74%, was generally higher than specified. This sample clearly fared better than the Nexus NX3000 reviewed earlier at 150W and 300W. The Nexus is based on the same Fortron platform. However, the 2~3% difference is within typical manufacturing variance; another pair of samples could well be be reversed in their efficiency.

Fan Voltage: It is evident that there is a thermistor in the PSU controlling the voltage to the fan. The fan voltage at a low 5.3V but climbed to about 7V before stabilizing at the low 65W load. A high 11.7V was reached after 10 minutes at the 90W load. This suggests that the thermistor fan controller circuit in this PSU is the stock Fortron version. (If so, with a "normal" 35-40 CFM fan, the standard Fortron would be LOUD even at modest power output levels.) It is a surprise that the thermal circuit was not removed given that the Verax fan itself has a self-contained thermistor speed controller.

Noise was measured within 1-2 cm (less than 1 inch) from the edge of the PSU fan exhaust, not in the airflow path. At the starting voltage of 5,3V, the noise is so low as to be inaudible beyond about 6 inches. There is no way I could measure this noise with any accuracy at all.

The quality of the Verax fan noise is different from any other fan I've listened to -- and I have listened to way too many. Rather than the hmmm or brrrrr from most fans, the Verax has more of a high frequency static-like quality, with very little low frequency content, considerably less low frequency noise than our reference Panaflo 80mm L fan. On the SLM, there is a peak centered around 10-12 KHz, and this correlates to the static-like high frequency noise I heard. It sounds like random static electronic noise.

As the fan speeds up, this noise becomes more steady, turning into something like a higher pitched (higher than usual) buzzing. At 300W, the noise is substantial, and there is some high pitch whine component that is not evident at lower power.

Case Temp (with the 100W bulb turned on) was 30C at 65W. The temperature rose to a maximum of 33C at the 150W level, but dropped to 31C at 300W when the fan was presumably spinning at full speed and thus providing more cooling of the case interior.

Power Factor was not notably high or low, ranging from 0.62 to 0.69 depending on load. The Nexus NX3000 measures almost exactly the same.

CONCLUSION

The Verax F300PPFC-80KP has

  • good air vents (even with a stamped fan grill);
  • wiring and connectors appropriate for desktop PCs;
  • stays very quiet to well beyond typical desktop PC power needs,
  • maintains very tight line regulation throughout the power range,
  • has high efficiency and good heatsinks for good cooling, and
  • survives 20 minutes of full power operation without duress.

At typical low/idle to mid levels, this Verax PSU actually sounds a wee bit quieter than the current low-noise champ on our Recommended PSU list, the Nexus NX3000. The difference is small, and may depend more on the particular sensitivity of your hearing at higher vs lower frequencies. While it makes less low frequency noise than most fans, the Verax fan's acoustic signature has a curious higher frequency static-like quality. At high power levels, it is not quiet, but this is true of all the the quiet PSUs.

The question here is not really one of quality (it is good) or noise (it is very quiet). It is one of value. The Nexus NX3000 sells in the US for US$75. This Verax, which is based on the same Fortron PSU, is currently sold by PC Silent for EU$119.

The Verax F300PPFC-80KP finds a high position on our Recommended Quiet PSU list with a reservation about price.

Our great thanks to PC Silent (http://www.pcsilent.de/) for their Herculean effort to provide the review samples, and their kind support.

* * * * *

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