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