NesteQ ECS7001 700W PSU: A Modular Twist

Power
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7. TEMPERATURE & COOLING

Temperature control was acceptable, reaching a maximum temperature rise of 14°C. At full load, the exhaust temperature was 63°C, as long as the unit was running. After several minutes of running at full load, the system shut itself off. One possible explanation is because of the heatsink-mounted thermistor. At full load, the heatsinks are dissipating over 200W of power, which would make them quite hot. The system ran at the 550W test point without any problems, however.

8. FAN, FAN CONTROLLER and NOISE

The PSU fan stabilized at 3.9V shortly after turning on. The fan was clearly audible at this level, with a slight "chuffing" sound. Initially we thought that there might be something rubbing against the fan, but after checking all the internal wires in the PSU, we concluded that it's the fan. There's also an aspct of low frequency rumbling or hum. We've seen other PSUs with Young Lin Tech fans, but none of them have wowed us in sound quality or level. The overall level or volume was quite low, but the quality of the noise made it more obtrusive than it could have been.

The fan speed remained constant until the 200W mark, where the voltage to the fan rose slighly to 4.2V. There was no noticeable difference in the SPL or the tonality of the fan. After this mark, the fan speed continued to rise in linear, direct proportion to the intake temperature, all the way up to 37dBA. The fan speed seemed to be very temperature sensitive. Changing the speed of PSU test rig's Nexus exhaust fan cause an immediate change in the PSU fan speed as well. This lack of hysteresis causes the fan speed to change sharply and noticably. Slower changes in fan speed would be much less noticeable.

As we mentioned before, the PSU shut down at full load. There was no indication of electrical instability, leading us to believe that it was caused by a thermal overload. Our test is thermally very demanding, and it's not unusual for thermal shutoff to be triggered as maximum power is approached, usually after several hours of continuous testing with constantly increasing loads.

We decided to test sound level of the PSU in SPCR's newly constructed hemi-anechoic chamber. The ambient level in the usual live test room was 18dBA, and in the hemi-anechoic chamber, it was 11dBA.

SPL Comparison - NesteQ ECS7001
Load
Hemi-Anechoic Chamber
Ambient: 11 dBA
Live Test Room
Ambient: 18 dBA
43W
18 dBA
22 dBA
250W
25 dBA
25 dBA
550W
37 dBA
37 dBA

At no load (i.e. minimum noise level), the SPL of the ECS7001 measured 18dBA@1m in the chamber. The sound quality and "chuffing" did not change subjectively, although it was clearly limited to the precise location of the PSU, due to the near-absence of acoustic reflections. The higher SPL measured in the live test room was caused by reflections and higher ambient noise levels adding to the noise of the PSU.

At 250W load and 550W load, the SPL readings were the exactly same in the anechoic chamber as in the live room. With the ambient levels in either room considerably more than 5-6 dBA below the noise being measured, they had no impact on the measured SPL of the PSU.

We made sound recordings of the PSU in our usual live test room as well as the hemi-anechoic chamber. Feel free to judge for yourself how the levels differ, if at all.

MP3 SOUND RECORDINGS

These recordings were made with a high resolution, studio quality, digital recording system, then converted to LAME 128kbps encoded MP3s. We've listened long and hard to ensure there is no audible degradation from the original WAV files to these MP3s. They represent a quick snapshot of what we heard during the review. More details about how we make these recordings can be found in our short article: Audio Recording Methods Revised.

The one meter recordings are intended to give you an idea of how the subject of this review sounds in actual use — one meter is a reasonable typical distance between a computer or computer component and your ear. The recording contains stretches of ambient noise that you can use to judge the relative loudness of the subject. Be aware that very quiet subjects may not be audible — if we couldn't hear it from one meter, chances are we couldn't record it either!

Each recording starts with 6~10 seconds of room ambience, followed by 10 seconds of the product's noise. For the most realistic results, set the volume so that the starting ambient level is just barely audible, then don't change the volume setting again while comparing all the sound files.

  • NesteQ ECS7001 at Various loads in Live Test Room, 22-37 dBA@1m: One meter
  • NesteQ ECS7001 at Various loads in Hemi-anechoic chamber, 18-37 dBA@1m: One meter
    These sound file ranges over three load levels - 40W, 250W, and 550W. The highest noise level can be taken as equal to what you would find in our usual testing environment, as the device simply drowns out any background noises.
  • Ambient acoustics of the anechoic chamber vs the live room - Some of you will be interested to hear this difference. The recording begins with 8 seconds in the anechoic chamber, then 8 seconds in the live room, followed by a few seconds in the anechoic chamber. The SPL levels, as mentioned before, were 11 dBA and 18 dBA respectively. It's interesing to note that the hiss many SPCR forum members attributed to electronic noise is, in fact, not so; it's part of the live ambient, due at least partly, to reflections at higher frequencies in the room. This is obviously absent in the chamber. (However, we did make a change to a new microphone which also has considerably less noise than what we were using before the anechoic chamber, so some of the hiss in past recordings was caused by microphone noise.)

Sound Recordings of PSU Comparatives

  • Enermax Modu82+ 625W at 20~150W output, 19 dBA@1m: One meter
  • Enermax Modu82+ 625W at 300W output, 22 dBA@1m: One meter
  • Seasonic S12 Energy Plus 550 at 0~150W, 20 dBA@1m: One meter,
  • Corsair TX650W at 250W, 21 dBA@1m: One meter
  • Corsair TX650W at 300W, 23 dBA@1m: One meter

CONCLUSIONS

The NesteQ ECS7001 doesn't meet our highest standards for quiet computing due to chatter and low frequency sounds from the slow spinning fan. Still, In a room with higher ambient noise and/or damping (like thicker carpeting and furniture) than our normal live test room, a PC built for low noise powered with this PSU would be fairly unobtrusive at moderate loads. It's not ideal for those obsessed with silence, but maintaining a sub-25 dBA SPL at loads up to 250W is very respectable.

The electrical performance was very good. Voltages were very stable and ripple quite low at all loads, until the shutdown, likely due to thermal overload. We don't think the shutdown is a serious issue. It shows that the protection circuit works and the PSU became operational without showing any signs of damage almost as soon as the load/heat was removed. This isn't the first time we've seen a power supply not deliver its maximum rating in our thermally demanding test setup. Some of you may remember that a few didn't make it, sometimes in spectacular fashion. It's difficult to imagine a computer that would actually demand 700W of continuous power while being cooled with just one low speed 120mm fan as in our test setup. Chances are, if tested at typical room temperature as PSUs often are, the ECS7001 would deliver its maximum power without issues.

The modular-modular cable arrangement is novel, and could prove quite useful. If properly planned out, a system could be built with a bare minimum of cables connected to the PSU. However, it makes putting the system together a bit more of a jigsaw puzzle, possibly adding a level of complexity that some users might not want to deal with. Nonetheless, it's nice to see a new company come up with something innovative, and not just gimmicky.

At nearly $200, it's hard to recommend this unit over others that are available. Aside from the new cable design, there's nothing that makes the NesteQ really stand out from the crowd. Stability is not a concern provided you stay below the maximum rated power output, but noise quality and levels are bettered by many PSUs already on our recommended pages, often at considerably lower prices for similar or even higher rated power.

Much thanks to Acoustic PC for this review sample.

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SPCR Articles of Related Interest:
Power Supply Fundamentals
Recommended Power Supplies
Power Distribution within Six PCs
SPCR PSU Test Rig V.4
Enermax Modu82+ 625W
Seasonic S12 Energy Plus 550 and 650
Zalman ZM1000 heatpipe-cooled modular PSU
Seasonic M12-700
Corsair HX520 & HX620

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Discuss this article in the SPCR Forums.



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