Cold Test Results (~22°C Ambient)

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

Due to the unique thermal design of the Nightjar NJ700, we had to change our testing methodology quite a bit. As there is no airflow to assess, we placed a sensor on the bottom side of the chassis and measure its surface temperature instead. Note that these thermal results are not directly comparable with those obtained by testing regular air-cooled products.

As expected from a fanless PSU with this kind of power output, its efficiency is extremely high. Our measurements indicate that the SilverStone NJ700 surpasses the 80Plus Titanium requirements regardless of its input voltage. It has an amazing 95% average efficiency across the entire nominal load range when powered by an 230V AC source, which drops down by just 0.6% when the input is lowered to 115V AC. The efficiency at just 5% load is above 86% and the peak efficiency is above 96%.

As expected from any well-designed PSU without active cooling, the surface temperature increases almost linearly and in near-perfect alignment with the unit’s thermal losses. The surface temperature does reach over 38 °C, which is to be expected, as the body of the PSU itself partially acts as a heatsink. The heatsinks of the PSU do reach temperatures over 50°C when the power supply is heavily loaded but that is a perfectly safe figure for an advanced PSU. The primary side is getting a little bit hotter than the secondary side. 

SilverStone NightJar NJ700 : Inside & Out Hot Test Results (~45°C Ambient)
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  • Wrs - Saturday, December 11, 2021 - link

    Noise cancelation is already used in aviation headsets - realize it does cost something and sometimes a cheap pair of earplugs is more than sufficient. Those subway researchers didn't miss anything, they just wanted to point out the amount of noise. It's on subway riders to get earplugs or cheap passive headphones if they can't afford ANC, or learn to steady eardrums with a reverse valsalva. Typically 75dB is regarded as starting to cause hearing loss. That's 1000 times as intense as a somewhat noisy 45dB machine.

    Decibels are simply a log base 10 scale. If you raise the intensity by 5x, that's a 7dB gain. So 5 35dB fans that don't attenuate each other, 42dB. Every 2x is 3dB, 4x is 6dB, hope you get the picture.

    Sorry about your experience with Beats. Ive never tried them but wouldn't associate them with good value. Bose is generally the ANC standard. Apple's Airpods Pro and Max are also well regarded. I use a Max and though a hiss is impossible to negate entirely its kind of hard for me to even notice it. Unfortunately I do not know how the experience differs for someone with significant tinnitus (everyone has that ringing, it just varies to what degree).
    Reply
  • Wrs - Saturday, December 11, 2021 - link

    So the comments about PSU sometimes adding insignificant noise are practically true. If the rest of system is already at 40dB when the PSU tops out at 29dB, they're not moving to 41dB. And all of this is nowhere close to causing hearing loss. Reply
  • Oxford Guy - Friday, December 24, 2021 - link

    And the Seasonic ‘Snow Silent’ PSU that ‘could be heard from rooms away’?

    That’s a quote from the review here.
    Reply
  • Wrs - Saturday, December 25, 2021 - link

    I can't find a Snow Silent review from AT, but I did find a rather competent one done in 2015 by Tom's, where it was found relatively quiet to 50% but measured 52dB 1m away at 80%+ load, which I suppose is audible from rooms away (it depends on the frequency distribution). Perhaps half the name was a misnomer.

    Then in 2016 the same author reviewed a Prime Titanium 850W that stayed under 30dB until almost 800W. That's two orders of magnitude less sound energy.
    Reply
  • TheinsanegamerN - Tuesday, November 30, 2021 - link

    The last PSU that I owned, that was audible at all under load, was an old diablotek power suppyl with two 80 MM fans. Most moderen 120mm PSUs run cool enough and quiet enough that absent a totally silent system will be inaudible. Reply
  • Oxford Guy - Thursday, December 2, 2021 - link

    Many modern PSUs are audible. One of them, a Seasonic ‘Snow Silent’ model could be ‘heard from rooms away.’

    That is a direct quote from the Anandtech review.
    Reply
  • alcoholbob - Saturday, December 4, 2021 - link

    Both the TX-700 (which the NJ700 is based on) and the NJ700 had problems with audible coil whine even while idling, which were much worse than higher wattage Seasonic semi-fanless units while running fanlessly. The issue with these 700W models appears to be the fact that the coil whine is very high pitched, so its quite audible from several feet away.

    On higher wattage Seasonic units like the 850W or 1000W RMx series, there is coil whine but its much lower in frequency. Due to the Fletcher Munson effect, it sounds nearly inaudible, while the TX-700 and NJ700, as well as lower end 520W and 420W Nightjar models sound to me quite unbearably loud due to the high frequency nature of the whine.

    I find it much cheaper to simply get a Corsair RMx unit and just mod the fan with a low noise Noctua fan.
    Reply
  • Oxford Guy - Friday, December 24, 2021 - link

    I recall that it was fan noise not coil whine that made that PSU audible, according to the reviewer. Reply
  • ruthan - Thursday, December 2, 2021 - link

    Im only missing 2x EPS cable for some dual socket builds, 700W is enough for them.

    I had fanless Seasonic and Silverstones, in the past.. My expecience is than Silverstone have better cooling, it worked in machine, where Seasonic with same Wattage was overheating.

    But we need some head to head review.
    Reply
  • albaikinindia - Monday, December 6, 2021 - link

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