04-10-2018 07:41 AM
I have a brand new 720s that is awesome in every way...except the audio. It is fine when on battery but I get a background static or faint electronic buzzing sound when connected to power. I don't get this at all when running on battery, though the Realtek audio could be better. But the instant I connect it to the power I get the static. It is not terribly noticable when listening to something at high levels but it is annoying if charging while going to sleep to something (or if you just need a charge while listening to something).
I have tried new and old drivers, disabling the Nvidia card, changing power schemes, every sound setting, different wall sockets (both grounded and not) and nothing stops the static when I charge. Any idea from anyone, or Lenovo, if this is something known to occur, or something I just have to live with or is this a defect and something I should return the laptop for?
04-22-2018 06:51 AM
I am going to bump this up with some new information. I have a work colleague who bought the same exact model I have and he also has the same static, electronic interference or whine that I have when he charges. My laptop has started to make this same background noise even when it is running on battery. On charge the sound gets louder and worse, like a static hiss. I even tried newer Realtek drivers than the ones on offer at Lenovo, and while the sound is reduced with the newer drivers (and the notorious lag in sound is now gone) it is still there.
I am really afraid this is down to build. Which is a huge shame and is so dissapointing. I LOVE this machine, it is gorgeous and perfect in every other way. But I can't abide this bad sound. I am likely returning it and am now a little hesitant to get another Lenovo and am looking at the Asus Zenbook.
08-23-2018 09:07 AM
Just bumping this topic. I didn't find any reference to the issue in reviews, but it seems common. The jack has its own io interface seperate from the rest of the mobo and is connected by a ribbon cable to the motheroboard. Furthermore, that ribbon runs directly under (touching) the battery. I've been using bluetooth earbuds in the meantime, but I'm worried about sending this in for repairs as Lenovo directs me to Geek Squad (a service partner) and they'd just order a new part which might have the same issue if it's a design flaw.
08-24-2018 11:51 PM
So I've been doing some research and it might honestly just be the cable isn't shielded properly, not helped by the fact that they moved the audio jack down to the base--right near the audio. I might try to shield it myself, but will return it if that does work. No reason to waste my time if it's down to a design flaw. I still can't figure out why the audio io was separated from the rest of the ports because it's almost guaranteed to pick up intereference right next to the battery. Again, no issue when using bluetooth earphones or an external sound dongle, but there's only one legacy usb port and the dongle takes that up which means I can't use my other peripherals. It really is a drag since Lenovo got everything else right with this model (and finally a matte screen on one of these ultrabooks!).
08-25-2018 01:16 PM
That was one of the first things I tried. It's not coil whine, it's pretty clearly the audio cable picking up electrical interence because touching the psu and is not properly shielded...which also explains why the noise is significantly worse when the AC is plugged in. The reason your 720s 14 doesn't have it is becausethe 3.5 mm jack and audio is located away from the psu up near the usb ports. That's my hypothesis, at least. between this and the throttling issue, I'm going to be pretty hesistant to pick up another Lenovo device if I end up returning this one.