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Joined: Feb 2016
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Hey,
I have a new Roland LX-7 DP (Here for less than a month). Whenever I plug in a cable into the "Audio In" jack, I start hearing some static noise, and sometimes buzz sound. (Depends on the cable) I tried various cables, of different qualities - all of them seem to cause this. At lower volumes (~60) it's barely noticeable - and I have to put my ears near the speakers or have a really silent room in order to notice it. At higher volumes (90~100), it can be pretty much annoying.
As I mentioned, this sound is only heard when a cable is plugged in the input jack (doesn't matter if there's a device connected to it). When the cable is not plugged in, the speakers are pretty much silent.
I am wondering what's causing this, and how can I avoid it. I've read some posts and webs claiming that ground loops could cause some humming sound, and that filters could help with these.
I am not really familiar with these stuff, so I would like to receive your opinions regarding this issue. Could it be some dust that entered the jack somehow? Bad cables? Electricity? The DP itself?
Thanks.
P.S. - I forgot to mention that if I plug in headphones, the static noise is then heard from them instead of the regular speakers. (Ofcourse that without the cable connected at the "Input" jack the headphones work well, just as the speakers do)
Last edited by barakbk; 04/04/16 01:35 PM.
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doesn't matter if there's a device connected to it If there is nothing at the other side, your cable act as an antenna and produce this noise. With a sound source, this shouldn't be so loud. You could also have ground loop noises if the sound source is linked with both an audio and a USB cable. Is the cable very long ?
Last edited by Frédéric L; 04/04/16 01:38 PM.
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The sound exists even when there's a device connected at the end. (Tried both my Galaxy S6 with a short cable, and my Desktop with a 5m cable) I disconnected the USB and all other connections when testing it.
I should make it clear that the sound is not intolerable. It's just annoying when the volume is high and I know that it's somehow related to the fact that I connected a cable.
Last edited by barakbk; 04/04/16 01:40 PM.
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With only a Galaxy S6, there is no path for a ground loop... So I don't think a ground loop filter will help.
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Any other ideas? By the way, when plugging my S6 into my Desktop's speakers directly, using the same cable, everything works well. Couldn't this still be related to the AC outlet, or maybe the external power supply?
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I have the same problem with my previous gen. hp504. Maybe it's the same all across the line. It's present even when I connect my phone (S5) with the piano with a short 1m cable. But since the speakers in the piano are nothing to write home about and since I can't use them for VST playback, since connecting both the PC to the line in and the piano to the USB results in a high-pitched ground loop noise, I kind have given up on the line in. Would be interested in knowing if it's the same for everybody else and if there's a solution for it or not.
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I have similar problem with LX-7, MacBook Pro and Focusrite Saffire Pro 24DPS. But in my case this is for sure ground loop noise issue and I am 100% sure it is LX-7's mini-jack audio input which is not correctly grounded; its audio input is unbalanced! I can hear "static noise" as you described when I connect my piano to MacBook Pro via USB, MacBook Pro to an audio interface via FireWire, and the interface back to the piano via mini jack cable. If all devices are connect to mains, I can hear loud noise. Fortunately to me, the interface (Focusrite) can be powered via FireWire without mains connected. Then, the noise is reduced to level I barely can hear it. I am afraid I cannot hear any noise if (1) I connect devices like mobile operating on battery or (2) there's nothing connect on the other side. It's only problem when I have the configuration above and it looks to me a little bit like something else. To eliminate ground loop noise or any noise, some suggest two DI boxes: one that converts unbalance signal to balanced and the other to convert the signal back to unbalanced. It's only a thought and I am sure someone else can provide better solution
Last edited by Celdor; 04/05/16 05:55 AM.
Zbigniew
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Hi I've been lurking here for a while but this is my first post! You can get ground loop isolators. They're little boxes with two 1:1 transformers in there. Here's an example:- https://www.hwaudio.co.uk/Product/QTX-35mm-Jack-Ground-Loop-Isolator-p430091This should solve your problem and they are very inexpensive. Steve
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Hey Steve,
Did you post the "Ground Loop Isolator" as a solution for my problem as well? Or was it referring to Celdor's problem?
I am considering purchasing one as well, though as others mentioned before, my problem doesn't seem related to a ground loop issue, as it happened with a mobile device as well.
Could my problem be related to the amplifier? or the soldering? or maybe some dirt?
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Hi
No, my response was more aimed towards Celdor. You've eliminated ground loops by using your mobile.
I'd try replacing the cable - a lot of those 3.5mm > 3.5mm cables are cheap rubbish and sometimes are not even shielded.
Steve
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