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Post by quamman on Mar 12, 2018 23:07:46 GMT -5
i am fighting a ground loop buzz as well. My system is dead quiet till the Sherbourn’s try to process any type of signal, yesibsaid Sherbourns as in 2 seperaate pre/Pro the 7020c4 and the 7030. Both have a high pitched ground loop when I listen to music through my Apple TV , or music from my fire tv , or anything from my Samsung 4k player . As I switch through the menu it will make itself known and go away. When I listen to music it is constant. Strangely on my Apple TV when I pull up movies through VUDU it quietens down quite a bit and is Almost not noticeable. Also strangely I can come in and turn everything on and listen for an hour or two and hardly hear anymore turn it off and come back a couple hours later and turn everything back on and behold it’s back . After much investigation I have tracked mine to the source being the tv . I tried a couple other TVs only to have the same noise . I can turn my tv off and the noise will disappear completely. I can also leave the tv on but remove the HDMI from it and the sound disappears. Ultimately my noise is being generated through the hdmi for some reason . All TVs tested are the same and all have two prong cords. So last night I ordered some ferrite magnet filters to clamp on the hdmi at both ends one at the tv and the other at my Sherbourn in hopes this will break up or disrupt the interference being shared between the two . I have not used them for many years as I have not had this problem series until I got my Sherbourn pre/pros. Before in the past had used them many times on audio patch cords and power cords with success. I’m hoping once again it will work for the HDMI interference. Once I receive them I will update wether it was successful or not .
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Post by quamman on Mar 16, 2018 9:20:58 GMT -5
Update , I have ordered some of the ferrite beads for the hdmi but I found I still had one with my test set from work that already has them installed drone manufacturing. I installed it and while it reduced the amount of feedback it’s still present so looks like I will be canceling my Oder from amazon before they have a chance to ship although it might be from my TVs power cord . It is only 2 prong from factory donut should not offer its own ground loop potential but I might chose to keep order placed as it’s only $9 for the beads and might prove useful in future and maybe on the tv . As a further note , everything I have is connected to a Panamax 5500 and I have also ran a new electric outlet. My noise was not audible till I acquired my Sherbourn Pre/pros . I will post any update I find to be useful in finding my loop. Were you able to make any headway on yours? Were you able to isolate the source ?
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Post by pachieh on Mar 16, 2018 13:04:29 GMT -5
Yeah, it's the Denon. I have a ground differential between the ARC and the Denon since I'm using RCA outs of the Denon and the Denon has no ground electrically. Not much I can do until I get rid of the Denon and move to XLRs.
My Ayre QB-9 is XLR to the ARC and it's perfectly quiet.
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Post by quamman on Mar 18, 2018 10:12:27 GMT -5
A little further update . I was able to specifically nail my noise down to either 1080p, auto, or pass through video settings . If I set my Sherbourn back to 1080i my noise goes away. I have tried turning off all features of the tv so thee are no enhancements to the picture and my 4k color settings are off as well but the noise will still appear under the 1080p, auto, or pass through settings . Even trying an older 1080p Sanyo tv instead of my 4k Samsung I still get the same results. I have a workaround picture but 1080i is not ideal and would like to find a solution to acquire my 1080p back or even allow pass through and my 4k player may be able to display its 4k content as well , on that part I’m not as certain if it will allow the 4k to pass through as it is not supposed to do any video processing under pass through mode . I guess maybe a call is in order Monday as I also have a firmware question.
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Post by quamman on Mar 18, 2018 11:33:56 GMT -5
Also a further note , my noise does not get louder with brighter scenes . And the only thing that has a ground in my setup Is the Sherbourn pt7020c4 . Was same issue with the pt7030.
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Post by 405x5 on Mar 18, 2018 12:48:29 GMT -5
It just occurred to me (after seeing this thread still with life).
I’ve been in this game longer then I care to admit (50 years).
In the earlier days of that time, I’ve needed to address noise associated with turntables and such, but never a ground loop.
Bill
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Post by quamman on Mar 18, 2018 13:08:57 GMT -5
It’s frustrating for sure . Prior to the Sherbourn’s I was using a Onkyo 703 avr for pre outs to same amps and never had the noise till I got the Sherbourn and now using HDMI . I also have a Onkyo 656 on same Panamax that is connected to some Paradigm speakers also all connected to tv via HDMI but does not have the noise . Yes I know the Sherbourn have external amps thrown into the equation but it all still comes down to the HDMI causing the squeel. The Sherbourn has an open mic background noise floor in general is best way I can describe it . Anytime you scroll through a menu or play music anything that it would have to process the noise kicks in . Other than that the Sherbourn are dead quiet . I don’t know there nature but it’s as if they sit in idle and then turn on to process once audio is sent . I also have them connected to some la Scala’s which are not forgiving speakers by any means . I can switch my speaker leads over to my Paradigm and is not nearly noticeable unless your ear is at the speaker , but they are not as sensitive as the la Scala’s . While the Sherbourn no doubt is a upper end pre/Pro vs my Onkyo with pre outs I hate the thought of having to live with the noise floor . But the sherbet do sound absolutely amazing with the la Scala’s and at least the noise floor does not amplify with volume.
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