A/C adapter buzzed really loudly
347725
While the fountain is a nice design and the cat loves it, the AC adapter buzzes really loud after only being plugged in for a day, the buzzing is so loud that we had to stop using the bowl. A shame because kitty liked it!
2378944
I'm sure this was fine for a monitor power supply, but it produced an unacceptable RF noise when used as a power supply for an audio amplifier.  I also question the power output. I noticed no gain from the original 2A power supply, just noise.
2542306
I just set my fan up and I am surprised how loud the hum of the engine is. Not quite what I expected.
1683033
The adapter I got works great and the fast charger goes from 20% to 100% in like fifteen minutes, but it is so noisey.
2575323
Do not buy this product if you will be using this AC adapter with a laptop that will be then be plugged into an external PA mixer of powered speaker. I bought this as an extra to take with me when I do DJ or music jobs to play backing tracks on my computer or Virtual DJ Pro. The last two jobs I had I noticed a buzzing of the speakers, which is quite audible in between songs or on quiet selections. I tried different cables, different AC outlets, everything...until I pulled out the this AC adapter. VOILA...silence! I just got home, set everything up, and tried it again. YEP, there it was, and then tried it with the OEM adapter from Lenovo, and it was GONE, so there is obviously a ground or electrical problem on the this one, but if you're just using it to power and charge your laptop for home use, it's fine.
4200143
I tried using this to power a device that was near some sensitive equipment. The equipment gave off crazy readings until I unplugged this adapter.

I got 4 of these things and they all did that. I ended up using a different AC adapter which did not produce the noise.

If all you need is power, this should do it, but it won't be very clean power.
1523209
Power supply was loud ,making noise all the time and to make it bad didn't work
719492
Very week fans. only .7A Shouldn't state High Static in the title. I bought 3 of these and can't use them on my radiator.
3403687
it works fine but makes a loud roaring noise. very noticeable while inside the vehicle with the windows up.
459404
Vibration was great. Much better than just gluing a nut to the motor shaft like I have done in the past. But, wow, did this thing suck power and it also created a lot of noise across the whole board. I found a few places that talked about adding a capacitor across the two leads on the motor and also adding a capacitor from each lead to the motor casing.  Doing this helped reduce the noise. I had to switch from a 7805 to a 317 in order to handle the power drain.
1468142
This charger has worked well for the 3 months or so that I have been using it. The LED used to indicate that AC power is connected is not too bright and I like that. The overall build quality appears a little bit cheap relative to the original charger that came with my ASUS laptop. The thing that drives me nuts about this charger though is that it emits a high frequency buzzing noise (~12kHz) every time there is any kind of loading. So if the laptop is just sitting there fully charged then no noise but as soon as I move the mouse the charger responds by squealing. It is definitely loud and noticeable even when a TV is on at a reasonable volume. I find myself fixating on the damnable buzzing noise as I am using my laptop. I would only reccomend this charger to someone I hated because I know that it would slowly drive them insane.
3774685
This will be my fourth A/C this summer. AC's nowadays seem so cheaply made and noisy! First I tried the top-rated LG 8000 BTU. It cooled great but was very noisy with a flawed filter design. That was returned. Next I ordered the top-rated Frigidaire 8000 BTU. Unfortunately, it came damaged and had to be returned so I went and purchased one locally. The Frigidaire seemed very cheaply made, did not cool as well as the LG and was loud and noisy. That one was also returned. Then I heard about the Haier. Although it is more expensive than the others it claims to be "Ultra" Quiet (and there's a picture of a sleeping baby on the box!) I received it yesterday. It's a larger, heavier unit the the other two. I like that the vents face up to eliminate direct blowing. Relatively easy to install. I was surprised that the bar that holds the AC against the window had no hole for attaching to the window - just two screws on the side flaps. Because of this the unit can be easily slid side to side. Not a big deal I suppose. Anyway..The unit cools very well. It did make the usual start-up noises but it eventually subsided. The unit IS quiet but I wouldn't say "Ultra" quiet. It does make noise. A little buzzing here..some rattling there. The fan is *much* quieter that the other A/C's I tried and I like the unit so far. I will call Haier to see if there's something I can do to kick it into "Ultra" quiet mode (haha). I don't want to try any more A/C's!

UPDATE: August 4. This unit started exhibiting an annoying pulsating sound along with some rattling. I called Haier and explained it to them and they suggested I return it. So, I ordered another one and sent this one back. The new one did not have that pulsating or rattling sound. Now that I've had one of these for a bit I will say this: the "High" and "Med" settings do seem a bit quieter than the many other AC's I've had (LG, Frigidaire, SPT, Sharp, etc). Of course, there's always going to be some noise when the compressor kicks in. On the "Quiet" setting this unit is really quiet - probably the most quiet I've ever had - but again the compresser will still make some noise when it kick in. You could say it's "Ultra" quiet when set to "Quiet" and the compressor is not running. Once you've reached a desired cooling temp and then set it to Quiet mode (and raise the temp so the compressor doesn't kick in) it's very, very quiet.
1283364
This is the second AC adapter to go out on me. Tested on multiple booms and I received a high pitch tone consistently on all devices
566365
0.7 Amp label on the motor.  It's louder than the rickety one that was offered to the circular file.  Also, I had to reverse mount the fan as this one spins in the opposite direction needed.  Loud, improperly mounted, and mislabeled - there you have it.
3986411
The fan itself is quiet but the unit buzzes louder than the fan operates and I can't figure out which part of the housing is generating the buzz. It is positional because I can move it slightly to make it stop, for a moment. Something inside the unit may be unbalanced. Mine arrived with 4 wires (including ground) and no instructions on what to do if you only have standard 12-2 Romex (3 wires). This does not have a light so it seems unnecessary to have this 4th wire. I believe it is for the humidity sensor. So basically I bought a fan with humidity sensing that won't operate that way because it requires more than standard 12-2 wiring. What is the fix for this?
161598
As soon as I plugged it in it started making ame extremely loud noise and did not stop u til I unplugged it to send it back.
2080829
I connected this cable from a laptop to an external LCD monitor that has built-in speakers.  The video signal was OK, but the audio made a buzzing/humming noise even when the volume was very low.  I read another review that this may be caused by the low power video signal coming out of the laptop, but I still decided to try it out in case the noise was bearable; unfortunately, that was not the case.  I returned the item the following day and got a full refund.  My setup works a lot better when I used a separate stereo cable for the audio.