Guest thathifiguy Posted February 24, 2017 Posted February 24, 2017 Hi all, Last night was the first night in a while where I had my place to myself and wouldn't you know it, I happened to notice something as a result. In my main room, I have home theatre and hi-fi combined. The components are: LG 55EC930T OLED TV Denon AVR-4520 NAD M2 Apple TV PS4 Cambridge CXU PSB Synchrony One Fronts and Centre PSB Imagine X1T Surrounds PSB Sub Series 300 Subwoofer I have set the system so that when being used for home theatre, the Denon has the front L/R preouts connected to the single ended input on my NAD M2 (which is set to fixed gain mode). I noticed last night a cyclic 'crackle' coming from the speakers only when the amp is set to the single ended input. I proceeded to examine what the cause was. Disconnecting the RCA cable from the NAD eliminated the noise clearing the M2 of any wrong doing. Ok, so the issue is caused up the chain. I reconnected the RCA cable and disconnected the Denon from power, the noise was still there. I tried disconnecting the aerial from the TV (I have heard this can cause ground loop issues), the noise was still there. Finally, I disconnected the television from power and sure enough the noise disappeared leading me to believe that the TV is injecting noise into the Denon via the HDMI connection which is then passing it on to the M2. I have two powerboards there, one is a Monster HTS950 which supposedly has 'Clean Power' and features two bays of four connectors that are in isolation, the other is a Belkin Pure AV Silver Series 8-Way board which is supposed to offer similar isolation, except it has isolated pairs rather than quads. The M2 was originally connected to the same board as the OLED, but even switching boards resulted in no change. Does anyone have any ideas on a cost effective way of tackling this problem? I'm renting so anything regarding any work on the mains is a no go, it will have to be something I can add in.
Jventer Posted February 25, 2017 Posted February 25, 2017 (edited) I am not sure if you have done the following. Start with the Monster powerboard. Use the same side of the powerboard, for example TV, Denon, M2 is noise still there, try changing say the tv to the other isolated side, if either these works you are well away. If you managed to get rid of the sound add the other devices one by one. In other words not isolated. I don't know about the PS4, but the Apple TV will only have a 2 prong plug and in theory could be excluded from the test. If above fails, do you perhaps have a different set of interconnects. I do not fully understand this bit: "Disconnecting the RCA cable from the NAD eliminated the noise clearing the M2 of any wrong doing." Maybe some other members with similar equipment can help. Edited February 25, 2017 by Jventer Typos
Weka Posted February 25, 2017 Posted February 25, 2017 With everything connected up, does unplugging the HDMI lead from the TV stop the noise? Something else you can try if the TV has the usual IEC C7 (figure 8) connection, is to reverse the mains polarity by rotating the IEC plug by 180 degrees in the inlet socket. This sometimes makes an improvement on unearthed double insulated devices. Another test would be to try a screened power cord to the TV - use a C14 to C7 adapter on the end of an existing screened IEC power cord if there is sufficient clearance at the TV inlet socket. Best of luck and make sure all your power cords are well separated from signal leads where possible.
Guest Posted February 25, 2017 Posted February 25, 2017 Sorry, I know this is completely off topic, but why do you have a Denon *anything* in a system with a NAD M2?
Guest thathifiguy Posted February 25, 2017 Posted February 25, 2017 I do not fully understand this bit: "Disconnecting the RCA cable from the NAD eliminated the noise clearing the M2 of any wrong doing."Maybe some other members with similar equipment can help. What I mean here is that by disconnecting the RCA cable from the NAD, the noise stops. This suggests the issue is earlier in the chain.I will try those other suggestions you have made and update.Sent from my iPad using Tapatalk
Guest thathifiguy Posted February 25, 2017 Posted February 25, 2017 With everything connected up, does unplugging the HDMI lead from the TV stop the noise? Something else you can try if the TV has the usual IEC C7 (figure 8) connection, is to reverse the mains polarity by rotating the IEC plug by 180 degrees in the inlet socket. This sometimes makes an improvement on unearthed double insulated devices. Another test would be to try a screened power cord to the TV - use a C14 to C7 adapter on the end of an existing screened IEC power cord if there is sufficient clearance at the TV inlet socket. Best of luck and make sure all your power cords are well separated from signal leads where possible. I haven't tried disconnecting the HDMI cable to the TV yet, but I will. Unfortunately this model from LG has a hard wired connection so I am unable to test it with different mains cables.Sent from my iPad using Tapatalk
Guest thathifiguy Posted February 25, 2017 Posted February 25, 2017 Sorry, I know this is completely off topic, but why do you have a Denon *anything* in a system with a NAD M2? The M2 is a stereo amplifier, it powers my main speakers, but something is required to drive the remaining channels of my 5.1 system. The Denon and M2 only play together when using surround sound.All my music sources connect to the M2, AV sources to the Denon. I don't see why this would present an issue?Sent from my iPad using Tapatalk
Jventer Posted February 25, 2017 Posted February 25, 2017 5 minutes ago, thathifiguy said: The M2 is a stereo amplifier, it powers my main speakers, but something is required to drive the remaining channels of my 5.1 system. The Denon and M2 only play together when using surround sound. All my music sources connect to the M2, AV sources to the Denon. I don't see why this would present an issue? Sent from my iPad using Tapatalk What the poster is trying to say is that the NAD M2 is so good that it should not be connected via the Denon. I think you have answered the question. 2 channel is M2 HT is via M2 for fronts and the rest via Denon. I get it.
andyr Posted February 25, 2017 Posted February 25, 2017 11 hours ago, thathifiguy said: Hi all, Last night was the first night in a while where I had my place to myself and wouldn't you know it, I happened to notice something as a result. In my main room, I have home theatre and hi-fi combined. The components are: LG 55EC930T OLED TV Denon AVR-4520 NAD M2 Apple TV PS4 Cambridge CXU PSB Synchrony One Fronts and Centre PSB Imagine X1T Surrounds PSB Sub Series 300 Subwoofer I have set the system so that when being used for home theatre, the Denon has the front L/R preouts connected to the single ended input on my NAD M2 (which is set to fixed gain mode). I noticed last night a cyclic 'crackle' coming from the speakers only when the amp is set to the single ended input. I proceeded to examine what the cause was. Disconnecting the RCA cable from the NAD eliminated the noise clearing the M2 of any wrong doing. Ok, so the issue is caused up the chain. I reconnected the RCA cable and disconnected the Denon from power, the noise was still there. I tried disconnecting the aerial from the TV (I have heard this can cause ground loop issues), the noise was still there. Finally, I disconnected the television from power and sure enough the noise disappeared leading me to believe that the TV is injecting noise into the Denon via the HDMI connection which is then passing it on to the M2. I have two powerboards there, one is a Monster HTS950 which supposedly has 'Clean Power' and features two bays of four connectors that are in isolation, the other is a Belkin Pure AV Silver Series 8-Way board which is supposed to offer similar isolation, except it has isolated pairs rather than quads. The M2 was originally connected to the same board as the OLED, but even switching boards resulted in no change. Does anyone have any ideas on a cost effective way of tackling this problem? I'm renting so anything regarding any work on the mains is a no go, it will have to be something I can add in. You have an annoying problem but as you have quite a few components, diagnosing a solution remotely is going to be difficult. I am picking up on what you said: "Finally, I disconnected the television from power and sure enough the noise disappeared leading me to believe that the TV is injecting noise into the Denon via the HDMI connection which is then passing it on to the M2.". You haven't said what is plugged into your power boards but, seeing as you are in Melbourne, I could lend you something which just may make the noise go away. Try it out ... it may ... or it may not! Assuming you can plug your TV set into a wall socket (not a power board), I am suggesting you try one of my 'DCbloks' between the TV and the wall socket. This will block any DC which you might have on your mains, from getting into the TV. It could be that DC on the mains is "annoying" your TV ... which, as you say, is then injecting noise into the rest of your system. Stop this DC ... and there may be no more noise? I also have an isolating transformer that will do a similar thing ... but has additional benefits. Try out each one! The isolating transformer solved a problem in my last house - it stopped hum coming through into my hifi system, when the preamp selected the TV as input. PM me if you're interested - you can come over and collect them, tomorrow. It will be a very quick test - and, yes, it's an off-the-wall suggestion - but either one of them will kill the noise ... or it won't! Regards, Andy
Jventer Posted February 25, 2017 Posted February 25, 2017 14 minutes ago, thathifiguy said: What I mean here is that by disconnecting the RCA cable from the NAD, the noise stops. This suggests the issue is earlier in the chain. I will try those other suggestions you have made and update. Sent from my iPad using Tapatalk I think this may not mean what you think. Why does the problem stop if you unplug the RCA? In my understanding this is part of the problem. You have a ground loop because of that RCA cable and possible other issues. Please try my suggestions and let us know what the results are.
Jventer Posted February 25, 2017 Posted February 25, 2017 @thathifiguy what @andyr is suggesting is very good advice. If I were you I would take up the offer.
Guest Posted February 25, 2017 Posted February 25, 2017 21 minutes ago, thathifiguy said: The M2 is a stereo amplifier, it powers my main speakers, but something is required to drive the remaining channels of my 5.1 system. The Denon and M2 only play together when using surround sound. All my music sources connect to the M2, AV sources to the Denon. I don't see why this would present an issue? Sent from my iPad using Tapatalk Sure, there should not be an issue. But even the most expensive Denon AVR is a *Lada* compared to the *BMW* M2.
JohnL Posted February 25, 2017 Posted February 25, 2017 (edited) 3 hours ago, johnmath said: Sure, there should not be an issue. But even the most expensive Denon AVR is a *Lada* compared to the *BMW* M2. Well then maybe you should just buy him a M17 and a M27 .............so we can all sleep tonight!!!! Edited February 25, 2017 by JohnL
Guest thathifiguy Posted February 26, 2017 Posted February 26, 2017 Well then maybe you should just buy him a M17 and a M27 .............so we can all sleep tonight!!!! Good suggestion, I wouldn't say no to that!In all seriousness though, I'm more invested in the Hi-Fi and am more than satisfied with the Denon as far as home theatre duties are concerned.That doesn't mean though that I want audible noise when there should be silence!Sent from my iPad using Tapatalk
Guest thathifiguy Posted February 26, 2017 Posted February 26, 2017 You have an annoying problem but as you have quite a few components, diagnosing a solution remotely is going to be difficult. I am picking up on what you said: "Finally, I disconnected the television from power and sure enough the noise disappeared leading me to believe that the TV is injecting noise into the Denon via the HDMI connection which is then passing it on to the M2.". You haven't said what is plugged into your power boards but, seeing as you are in Melbourne, I could lend you something which just may make the noise go away. Try it out ... it may ... or it may not! [emoji3] Assuming you can plug your TV set into a wall socket (not a power board), I am suggesting you try one of my 'DCbloks' between the TV and the wall socket. This will block any DC which you might have on your mains, from getting into the TV. It could be that DC on the mains is "annoying" your TV ... which, as you say, is then injecting noise into the rest of your system. Stop this DC ... and there may be no more noise? I also have an isolating transformer that will do a similar thing ... but has additional benefits. Try out each one! The isolating transformer solved a problem in my last house - it stopped hum coming through into my hifi system, when the preamp selected the TV as input. PM me if you're interested - you can come over and collect them, tomorrow. It will be a very quick test - and, yes, it's an off-the-wall suggestion - but either one of them will kill the noise ... or it won't![emoji4] Regards, Andy This is an awesome offer Andy, thanks. I'll try some of the suggested troubleshooting first and if that doesn't reward me, I'll shoot you a msg.Sent from my iPad using Tapatalk
andyr Posted February 26, 2017 Posted February 26, 2017 1 minute ago, thathifiguy said: This is an awesome offer Andy, thanks. I'll try some of the suggested troubleshooting first and if that doesn't reward me, I'll shoot you a msg. Sent from my iPad using Tapatalk NP, Tarkan - luckily you are in Melbourne (so it makes it easy!). Andy
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