Hello Guest, if you are reading this it means you have not registered yet. Please take a second, Click here to register, and in a few simple steps you will be able to enjoy our community and use our OpenViX support section.
Results 1 to 7 of 7

Thread: Unusual Question - DC Thump from Audio Out on XTrend ET10000

  1. #1

    Title
    Junior Member
    Join Date
    Oct 2016
    Location
    Dublin, Ireland
    Posts
    27
    Thanks
    5
    Thanked 4 Times in 3 Posts

    Unusual Question - DC Thump from Audio Out on XTrend ET10000

    Hi folks,

    OK - this is an odd question so completely accept if it's outside the expertise of users here. But just thought I'd chance asking... My XTrend ET10000 has a stereo audio out on the back. The box is sitting beside an old stereo amplifier that only has twin rca inputs (the old red and white stereo leads). I love the amp (and the radio that's attached to it) so that's staying. I did think 'why not connect the XTrend to the old amp' for matches and the like to pump up the volume in the room a bit.

    So I did. And it works great - when connected. But I do get a big 'DC thump' from the speakers when I select the XTrend input on the amp. I had a look and my XTrend only has a two-core power supply cable. So the chassis of the XTrend box is clearly not grounded - and I would think that's the most likely cause of the crack/bang when I switch to it/select that input on the amp.

    So... has anyone grounded the case of their linux receiver? Is it safe to do so? Would love to hear some feedback on the idea. I tried using my google-fu to find the answer but haven't hit gold yet.

  2. #2
    Rob van der Does's Avatar
    Title
    ViX Beta Tester
    Join Date
    Apr 2010
    Location
    The Netherlands & France
    Posts
    36,270
    Thanks
    1,720
    Thanked 9,461 Times in 6,675 Posts
    First of all: I have my ET8000 (as test box) also connected to an amp via RCA, and I don't experience that issue. I say this to illustrate that thiis is not a general problem, but will be related to local circumstances.

    Grounding a STB can be a problem; especially when the distance between dish/antenna and STB is large, there is the danger of getting a 'ground loop'.
    Please see the attached document (hoping you understand German, but otherwise I'm sure you'll find some information yourself): vde0855_310108.pdf

    Help asked via PM will be ignored.
    The forum is there for help and all will benefit from your questions.
    NO CARD SHARING TALK WILL BE TOLERATED, LAN OR WAN, IN OPEN FORUM OR PM !

    English is not my native tongue.
    I apologise for all my grammar, spelling and idiom errors.

  3. The Following User Says Thank You to Rob van der Does For This Useful Post:

    flintdk (28-10-16)

  4. #3
    Joe_90's Avatar
    Title
    Moderator
    Join Date
    Mar 2014
    Location
    Wicklow, Ireland
    Posts
    4,244
    Thanks
    1,315
    Thanked 1,148 Times in 908 Posts
    Rob - Im just pointing out that in a domestic situation the dish/antenna would not normally be grounded, so you shouldn't encounter a ground loop scenario. In shared apartments or some other communal feed the dish/LNB/antenna/ distribution switches should be earth-bonded (grounded) to prevent fault voltages affecting other users. It's likely that the STB's phono connections have a floating voltage present and possibly a wire link from a earthed point on the amplifier to the ground side of the phono connectors may solve the issue. One for experimentation. I've had no such issues with more modern AV amps which are ungrounded.
    GB Quad Plus, Mut@nt HD51, AX HD61, 80cm dish and Supreme Dark motor. Sony TA-AN1000, Sony UBP-X800M2 Bluray, Odroid N2+ (CoreElec), Monitor Audio Bronze 5.1 speakers

  5. The Following User Says Thank You to Joe_90 For This Useful Post:

    flintdk (28-10-16)

  6. #4
    Rob van der Does's Avatar
    Title
    ViX Beta Tester
    Join Date
    Apr 2010
    Location
    The Netherlands & France
    Posts
    36,270
    Thanks
    1,720
    Thanked 9,461 Times in 6,675 Posts
    Quote Originally Posted by fat-tony View Post
    Rob - Im just pointing out that in a domestic situation the dish/antenna would not normally be grounded, so you shouldn't encounter a ground loop scenario.
    Well, that's actually causing a ground loop. Unless all are earthed on the same (very thick) lead. Especially when the antenna/dish is a bit away from the house (at the end of the garden, attached to a shed/garage), earthing bot antenna and STB will create the ground loop scenario.

    Help asked via PM will be ignored.
    The forum is there for help and all will benefit from your questions.
    NO CARD SHARING TALK WILL BE TOLERATED, LAN OR WAN, IN OPEN FORUM OR PM !

    English is not my native tongue.
    I apologise for all my grammar, spelling and idiom errors.

  7. #5
    Joe_90's Avatar
    Title
    Moderator
    Join Date
    Mar 2014
    Location
    Wicklow, Ireland
    Posts
    4,244
    Thanks
    1,315
    Thanked 1,148 Times in 908 Posts
    No - I'm saying the antenna or dish are NOT earthed (grounded).
    GB Quad Plus, Mut@nt HD51, AX HD61, 80cm dish and Supreme Dark motor. Sony TA-AN1000, Sony UBP-X800M2 Bluray, Odroid N2+ (CoreElec), Monitor Audio Bronze 5.1 speakers

  8. #6

    Title
    Junior Member
    Join Date
    Oct 2016
    Location
    Dublin, Ireland
    Posts
    27
    Thanks
    5
    Thanked 4 Times in 3 Posts
    Rob, Tony - thanks both for your input.

    My dish is not grounded. I did see some mention on here about grounding the dish to allow for static discharge - but I didn't act on it. The dish is bolted to the house. End of. And unless I messed up there's no contact between the dish and the cables running down to the box. So the double isolated linux box and the three 20m'ish runs of cable attached to it float probably at some non-zero voltage, relative to the ground of my amp.

    The amp in question is quite old (valve driven) - it's quite possible a more recent av amp would have some better sort of protection against this. So I'm not worried about a ground loop (but do appreciate the warning). I think I'll just make up a grounding lead, ground the case on the receiver and see what happens. I only hear the 'thump' when choosing inputs on my amp - will be pretty easy to tell if grounding the case works or not! Will post back sure when I get a chance to test it later.

    Thank you both for taking the time to reply.

  9. The Following 2 Users Say Thank You to flintdk For This Useful Post:

    Joe_90 (27-10-16),Rob van der Does (27-10-16)

  10. #7
    Rob van der Does's Avatar
    Title
    ViX Beta Tester
    Join Date
    Apr 2010
    Location
    The Netherlands & France
    Posts
    36,270
    Thanks
    1,720
    Thanked 9,461 Times in 6,675 Posts
    Quote Originally Posted by fat-tony View Post
    No - I'm saying the antenna or dish are NOT earthed (grounded).
    Sorry, I overlooked the 'NOT'

    Help asked via PM will be ignored.
    The forum is there for help and all will benefit from your questions.
    NO CARD SHARING TALK WILL BE TOLERATED, LAN OR WAN, IN OPEN FORUM OR PM !

    English is not my native tongue.
    I apologise for all my grammar, spelling and idiom errors.

  11. The Following User Says Thank You to Rob van der Does For This Useful Post:

    Joe_90 (27-10-16)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
This website uses cookies
We use cookies to store session information to facilitate remembering your login information, to allow you to save website preferences, to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.