nahsusu Posted February 14, 2015 Share Posted February 14, 2015 There will be a huge noise when use USB cable connecting the HD500 to computer. While no noise without USB cable. Please help to identify this problem. Thanks in advance I live in China , so I can't find any official after sale service , please tell me how to fix it by myself .... thank you very much ..... Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted February 14, 2015 Share Posted February 14, 2015 This is what is called a Ground Loop. Try plugging everything into the same power strip. Sometimes it is not possible to completely eliminate this. The problem is that the PC Ground is very noisy and the USB cable is grounded to your PC and to the Pod. I tried a USB isolator but it doesn't work with the Pod. There are some threads here showing how to eliminate the problem using a ground isolator between the Pod and your Amp. There is nothing wrong with your Pod so do not try to get it fixed. Quote Link to comment Share on other sites More sharing options...
cbrfreak Posted February 14, 2015 Share Posted February 14, 2015 You may need to use a laptop computer running on battery without power plugged in to remove the ground loop. Quote Link to comment Share on other sites More sharing options...
nahsusu Posted February 15, 2015 Author Share Posted February 15, 2015 This is what is called a Ground Loop. Try plugging everything into the same power strip. Sometimes it is not possible to completely eliminate this. The problem is that the PC Ground is very noisy and the USB cable is grounded to your PC and to the Pod. I tried a USB isolator but it doesn't work with the Pod. There are some threads here showing how to eliminate the problem using a ground isolator between the Pod and your Amp. There is nothing wrong with your Pod so do not try to get it fixed. It seems problem is not USB . I found it : when i touch the head of 6.5mm guitar connecting line , the noise is gone ... i used HD500 for almost 2 years , did not have such a problem untill last night ... is that something wrong with the Rectifier ? Quote Link to comment Share on other sites More sharing options...
nahsusu Posted February 15, 2015 Author Share Posted February 15, 2015 as Charlie already said above here, probably you have a ground loop problem.. much probably your PC is connected to the mains, and your POD is connected also to the same mains (grounded).. therefore when you connect also the POD to the PC you form a loop made of PC-->mains-->POD-->PC (closing the loop).. like often may happens, if there is a residual small passive current (due to interactions between devices connected at the same mains ground) running through the above loop, it disturbs the audio signal.. so you need to break the loop at one of its joining points in some way.. eg if you are using a laptop you can try running it on batteries, doing so you break the above loop in the joining point between PC and mains, or you can buy and use a HUM isolator/killer for the mains, which breaks the loop in the joining point between the mains and the connected equipments.. or a different HUM isolator made instead for USB.. also a power conditioner should work good It seems problem is not USB . I found it : when i touch the head of 6.5mm guitar connecting line , the noise is gone ... i used HD500 for almost 2 years , did not have such a problem untill last night ... is that something wrong with the Rectifier ? Quote Link to comment Share on other sites More sharing options...
pianoguyy Posted February 15, 2015 Share Posted February 15, 2015 touching something to make the hum go away IS a ground loop issue. By touching it, you complete the circuit and act as a ground. The issue could be in any of the things you're using. It could also be.... Where is your circuit breaker? Turn it off. Anything that gets turned off in the house from that one switch... Those could be the issue. Did you ever use a toaster in the kitchen while drying your hair in the bathroom and the lights go out? Too much load on the breaker. Its the same kind of issue. It could be something in a different room. ---------------------------------------------------- BUT... If you in China, any hum going on could just as easily be the government spying on your. Quote Link to comment Share on other sites More sharing options...
Charlie_Watt Posted February 15, 2015 Share Posted February 15, 2015 If it also goes away when you don't plug in the USB then it's a ground loop. Quote Link to comment Share on other sites More sharing options...
nahsusu Posted February 17, 2015 Author Share Posted February 17, 2015 if you didn't change anything in the way all the same things are connected together, and you didn't have the noise problem using also the USB connection till last night, I'd suggest to check if your jack cable is still ok, possibly try another one.. touching something to make the hum go away IS a ground loop issue. By touching it, you complete the circuit and act as a ground. The issue could be in any of the things you're using. It could also be.... Where is your circuit breaker? Turn it off. Anything that gets turned off in the house from that one switch... Those could be the issue. Did you ever use a toaster in the kitchen while drying your hair in the bathroom and the lights go out? Too much load on the breaker. Its the same kind of issue. It could be something in a different room. ---------------------------------------------------- BUT... If you in China, any hum going on could just as easily be the government spying on your. If it also goes away when you don't plug in the USB then it's a ground loop. ground loop ... how to fix it ? today i find when i touch any metal parts , the nosie is gone .... Quote Link to comment Share on other sites More sharing options...
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