AFD
2[H]4U
- Joined
- Aug 7, 2013
- Messages
- 2,154
I'd like to hear if it's the UPS, direct mains should give a smoother AC frequency.
Still haven't tried tried swapping to AC yet, though I did spend half the night getting out of bed to periodically unplug an insane amount of electrical devices around the house. Most were fine, but I did find a few others with the same high-pitched whine (from internal PSU or external power adapters), which would lead me to believe the issue isn't directly related to the UPS. EDIT: Accidentally fell asleep running stress tests.. woke up, and the whine was drastically quieter (still perceptible, but noticeably less so - especially when listening at off angles away from the intake/exhaust. Weird.)
If possible, test at another house to make sure this isn't caused by something in your house.
That's a very smart idea. I'm still waiting on my Char/Liz M1 carrying bag, but I'd like to take my rig to work and try that out (there's an equally insane amount of electronics everywhere, but I never hear whine from any of their power supplies).
As to the coil whine, they didn't mention any of it that I saw, which lends some credence to it being something specific to AFD's electrical environment.
There was a passing mention of whine and buzz, but they seemed fine with it..
Even from virtually inches away, only a trace amount of buzz could be reliably heard.
There's very little or no electronic noise (such as buzz, hum or whine) to be perceived.
It's such an oddly high frequency, that I'm certain many folks simply can't hear it at all depending on their hearing and age. My oscilloscope app on my phone is picking it up as ~15kHz (SPCR only measured to 11kHz, so I can't see a peak there), which is very close to the "mosquito noise" (LINK). So if nothing else, I shouldn't be able to hear it at all in a few years
It's important to note, however, that the semi-passive fan, which is tied to an internal temperature of 45°C in a sensor somewhere inside the unit, started at just 40W load after about 15 minutes, when the exhaust temperature read only 26°C.
I wonder if it would be possible to find and reposition the temp sensor to a slightly cooler location, so that the semi-passive feature might actually work as intended?
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