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Denon 2805 earthing query

Discussion in 'AV Receivers & Amplifiers' started by pcavelle, Aug 12, 2004.

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  1. pcavelle

    pcavelle
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    I just bought a Denon 2805 (to replace a Meridian 568) to use as a processor in my system. I'm not using it to power all channels, only centre & rears at the moment.

    I have to say its a great product and first impressions would indicate that the processing is better than my, admittedly 5 year old, Meridian 568 processor.

    Slight problem however - loud earth hum through front two channels. The front two channels are a Krell preamp (unity gain input) followed by Krell poweramp, so I'm using 2805 preamp out for these channels. There was no earth hum when the 568 was used until very recently in exactly the same manner.

    I've eradicated all variables I think ie cables, mains etc. I've changed DVD players too. The hum only occurs when the DVD player is attached / powered up, but as I've said I've tried an alternative player so I don't think it's the player itself.

    I've noticed that the Meridian 568 was eathed, the 2805 is not (ie 2 core mains).

    I therefore think there's an earth loop somehow between Denon & DVD player, possibly the Krell Pre, although I don't think the Krell is the culprit.

    I think I somehow need to equalise earth between the 2805 and DVD player. I've tried touching earth wires (from a copper radiator pipe) to chassis of the Krell & 2805 without any effect.

    Any other suggestions?

    Thanks

    Paul
     
  2. wookie

    wookie
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    Try an optical cable as it won't conduct the potential difference.
    Have you tried earthing both units casework together via signal/phono ground terminals?
     
  3. Reiner

    Reiner
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    I would also suggest to try the optical link first, with no coaxial or analog connection, but if necessary use the phono ground of the Denon to earth it to the Krell as suggested by wookie.
     
  4. pcavelle

    pcavelle
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    Thanks for the suggestion chaps - I was going to try optical and then I realised that my cheapo 'stopgap' DVD player did not have an optical-out.

    I have now wired the chassis of the Krell to the 2805 and the hum has almost vanished. There's still a tiny bit left but you have to be really close to the speaker to hear it.

    When my new DVD player arrives I'll switch to optical.

    Thanks for your suggestions.

    Regards

    Paul
     

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