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Thread: rice krispies and gl75

  1. #1
    Join Date: Feb 2011

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    I'm tony.

    Default rice krispies and gl75

    Help folks,

    My Lenco is crackling away whilst idling-stylus above the record!

    I tried re terminating the ground wire at the amp end-better but still not right.

    If i touch the tone arm or pick up I get an audible hum.

    redirected the ground wire away from power cable etc-made it better but the crackling remains.

    your thoughts folks!!!

  2. #2
    Audio Al is offline Pishanto Specialist & Super-Daftee
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    I'm Allen.

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    Needs more milk
    [

  3. #3
    Join Date: Jan 2009

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    I'm openingabottleofwine.

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    If you get an audible hum when you touch the pick up arm, then there is a problem with the earthing of the metalwork of the arm and/or the TT chassis. Are the two earthed together or separately?
    Barry

  4. #4
    Join Date: Feb 2011

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    Dont know Barry -will have look inside today see if anything obvious appears.

  5. #5
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    When I got my Lenco (a very early example of GL75), the factory wiring was very weird. It did not have a separate ground lead, and left and right signal returns were joined together and connected to tonearm ground. Needless to say, there were unhealthy amounts of hum.

    I changed the power lead to a 3-core flex and grounded the motor and the top plate to mains earth. After that, I separated the left and right signal returns and tonearm ground. At first I connected a separate wire for the tonearm ground, but there still was some hum. When I connected the tonearm ground to the top plate (grounded to mains earth), most of the hum went away, but I have never been able to get rid of it completely.

  6. #6
    Join Date: Jan 2009

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    I'm openingabottleofwine.

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    That is how I would arrange things - but it might be a good idea to check that the metalwork of the headshell is not also earthed through a connection to one of the signal returns.
    Barry

  7. #7
    Join Date: Feb 2011

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    Opened it up.

    The ground wire had been soldered with the wire from the arm but was just lying at the bottom of the plinth not connected to anything.

    I placed a crimp on it and attached it to a bolt under the chassis.....rice krispies are gone but its humming like a pish soaked tramp.

    Will have to do a bit of googling regards earthing points on the lenco chassis.

    Thanks for the advice folks ....im really struggling with getting to grips with vinyl (i hope its worth it!)

  8. #8
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    sounds like connecting it is producing a ground loop
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  9. #9
    Join Date: May 2011

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    Quote Originally Posted by wee tee cee View Post
    Opened it up.

    The ground wire had been soldered with the wire from the arm but was just lying at the bottom of the plinth not connected to anything.

    I placed a crimp on it and attached it to a bolt under the chassis.....rice krispies are gone but its humming like a pish soaked tramp.

    Will have to do a bit of googling regards earthing points on the lenco chassis.

    Thanks for the advice folks ....im really struggling with getting to grips with vinyl (i hope its worth it!)
    Tony theres a wire runs from a tab at the bottom of the arm to the earth post on the phono stage .
    I will try and get over this week mate .
    Regards
    Brian

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  10. #10
    Join Date: Feb 2011

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    will step away till help arrives.

    Checked lenco heaven-hum issues are rather prevalent!!

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