On 6/5/2015 1:33 PM, Michael Hennebry wrote:> It's a desktop in an old house. > The outlets have ground-fault protection, > but the third prong is ungrounded. >not sure how GFI would function at all without a valid ground, unless the GFI is wired to neutral, which is dangerous on its own. you might get a 3-prong-to-2-prong adapter and plug the PC into that, leaving the ground wire floating, and see if that works. As most desktops have the AC ground pin wired to the chassis, floating the chassis might well eliminate the hum. also, things like fluorescent lamps can greatly contribute to hum, although that often sounds like a buzz. lamp dimmers too, try switching any dimmers in the general area to either 100% on or totally off.> It's an Insignia NS-PAH5101 > It does not have a separate power source, > just plugs for the pink and green sockets. > The cables are pretty thin. > If the problem is shielding, > is there something I could do to shield the cables?not really, the wire itself has to be shielded coaxial wire. if its actually the headset itself, I'd suggest getting another one. I've had better luck with USB headsets of late instead of analog ones plugged into on-board audio, as the onboard audio microphone inputs are generally of very poor quality. -- john r pierce, recycling bits in santa cruz
On 06/05/2015 03:43 PM, John R Pierce wrote:> On 6/5/2015 1:33 PM, Michael Hennebry wrote: >> It's a desktop in an old house. >> The outlets have ground-fault protection, >> but the third prong is ungrounded. > > not sure how GFI would function at all without a valid ground, unless > the GFI is wired to neutral, which is dangerous on its own.very. it defeats gfi faulting principal entirely.> you might get a 3-prong-to-2-prong adapter and plug the PC into that, > leaving the ground wire floating, and see if that works. As most > desktops have the AC ground pin wired to the chassis, floating the > chassis might well eliminate the hum.no need. as he said "but the third prong is ungrounded".> also, things like fluorescent lamps can greatly contribute to hum, > although that often sounds like a buzz. lamp dimmers too, try > switching any dimmers in the general area to either 100% on or > totally off.correct. normally, repeat, normally, wiring for outlets and light are different wire runs, but they may be common leg of 240 mains at panel. <<>>> not really, the wire itself has to be shielded coaxial wire. if its > actually the headset itself, I'd suggest getting another one. > > I've had better luck with USB headsets of late instead of analog > ones plugged into on-board audio, as the onboard audio microphone > inputs are generally of very poor quality.even with usb headsets, quality/cost is to be considered. cheap preforms as cheap is. low the price, lower the quality of results. you get what you pay for. -- peace out. If Bill Gates got a dime for every time Windows crashes... ...oh, wait. He does. THAT explains it! in a world with out fences, who needs gates. CentOS GNU/Linux 6.6 tc,hago. g .
On Fri, 5 Jun 2015, g wrote:> On 06/05/2015 03:43 PM, John R Pierce wrote: >> On 6/5/2015 1:33 PM, Michael Hennebry wrote: >>> It's a desktop in an old house. >>> The outlets have ground-fault protection, >>> but the third prong is ungrounded. >> >> not sure how GFI would function at all without a valid ground, unless >> the GFI is wired to neutral, which is dangerous on its own.As I understand it, GFI sums the currents going into each prong. If the sum is not close enough to zero, it breaks the circuit.>> also, things like fluorescent lamps can greatly contribute to hum, >> although that often sounds like a buzz. lamp dimmers too, try >> switching any dimmers in the general area to either 100% on or >> totally off.No dimmers, but I tried turning off the overhead flourescent lights. No effect.>> not really, the wire itself has to be shielded coaxial wire. if its >> actually the headset itself, I'd suggest getting another one. >> >> I've had better luck with USB headsets of late instead of analog >> ones plugged into on-board audio, as the onboard audio microphone >> inputs are generally of very poor quality. > > even with usb headsets, quality/cost is to be considered. > > cheap preforms as cheap is. > > low the price, lower the quality of results. > > you get what you pay for.More precisely, you pay for what you get. Getting what you pay for is iffier. -- Michael hennebry at web.cs.ndsu.NoDak.edu "SCSI is NOT magic. There are *fundamental technical reasons* why it is necessary to sacrifice a young goat to your SCSI chain now and then." -- John Woods