Phono mains hum

Discussion in 'Hi-Fi and General Audio' started by ecosse_011172, Sep 11, 2008.

  1. ecosse_011172

    ecosse_011172

    Joined:
    Dec 6, 2007
    Messages:
    20
    Likes Received:
    0
    Equipment:
    Origin Live Aurora Turntable
    Tom Evans MicroGroove+ Phono Amp
    MF A3CR Pre Amp
    2 x MF A3CR Power Amp (bi-amping)
    ProAc Response D15

    I hear intermittent RFI hum when listening to the turntable, the flat seems to have lots of RFI (always clicks and stuff when lights are switched off) and I'm struggling to eliminate it.
    I've played around with the earh wires on the phono amp and pre amp to no avail.

    Any suggestions?
    Are the IsoTek or Russ Andrews silencers worth a go?

    Thanks
     
    ecosse_011172, Sep 11, 2008
    #1
  2. ecosse_011172

    robM

    Joined:
    Feb 6, 2004
    Messages:
    347
    Likes Received:
    0
    I remember a friend in a similar situation with his system. The RA silencers did nothing, but changing the lighting switches to new ones helped with the clicks along with putting some suppression caps across the L & N.

    You need to find out what is causing the HUM first, then tackle it.

    1. when did it start? when you first moved in?
    2. could it be that the evans stage is too close to the motor supply etc.
     
    robM, Sep 11, 2008
    #2
  3. ecosse_011172

    ecosse_011172

    Joined:
    Dec 6, 2007
    Messages:
    20
    Likes Received:
    0
    It has been since I moved in, it's a rented flat that the whole building was rewired and refitted just before I moved in.
     
    ecosse_011172, Sep 11, 2008
    #3
  4. ecosse_011172

    spica

    Joined:
    Aug 25, 2008
    Messages:
    310
    Likes Received:
    0
    Location:
    isotropic
    spica, Sep 11, 2008
    #4
  5. ecosse_011172

    ecosse_011172

    Joined:
    Dec 6, 2007
    Messages:
    20
    Likes Received:
    0
    After no joy whatsoever I sent the phono amp back to the manufacturer for test as unplugging every appliance in the house and changing cables, inputs etc. made no difference. Using the phono stage in my pre amp removed the hum using the same setup, cables etc.

    The manufacturer has found no problems and cannot reproduce the problem but suggests replacing the voltage regulators with newer improved ones at a cost of over 400 quid which I can't afford at the moment.
    I don't think I have any option but to get it back and sell it...:-(
     
    ecosse_011172, Oct 28, 2008
    #5
  6. ecosse_011172

    Andy 831

    Joined:
    Jan 19, 2006
    Messages:
    389
    Likes Received:
    0
    Location:
    Out on a wild and windy moor
    I bought and tried one of the Partridge step up transformers being sold as the "Martha"by a fellow ZG/Wammer, as a potential replacement for my Denon AU-300LC.

    I tried with numerous interconnects of varying length, tried to position it as far away from other kit as was possible within my set up, but I just could not stop the bugger from humming.

    Sent it back and it worked perfectly in Laurance`s system with no discernable hum. Which is also backed up by the number of other successfull sales that have been acheived with this step up.

    It seems to me that sometimes there is just no sane reason why a peice of kit interacts with other equipment. Although I am sure the electronics experts amongst us might have a different opinion. Maybe its just the SYNERGY thing coming into play again

    My advise would be sell it and try something else from a different manufacturer
     
    Andy 831, Oct 28, 2008
    #6
  7. ecosse_011172

    ecosse_011172

    Joined:
    Dec 6, 2007
    Messages:
    20
    Likes Received:
    0

    Thanks, I think I'll def try to sell it, put soem cash to it and try one of the WHEST Phono amps...
     
    ecosse_011172, Oct 28, 2008
    #7
  8. ecosse_011172

    SMEagol Because we wants it...

    Joined:
    Mar 23, 2007
    Messages:
    975
    Likes Received:
    0
    Location:
    Lancashire
    Last edited by a moderator: Oct 28, 2008
    SMEagol, Oct 28, 2008
    #8
  9. ecosse_011172

    Tim F

    Joined:
    Mar 23, 2004
    Messages:
    352
    Likes Received:
    0
    Location:
    London
    Hmm just a thought but it sounds like an earth loop.
     
    Tim F, Oct 31, 2008
    #9
  10. ecosse_011172

    ecosse_011172

    Joined:
    Dec 6, 2007
    Messages:
    20
    Likes Received:
    0
    Any suggestions on how to resolve it?
     
    ecosse_011172, Nov 4, 2008
    #10
  11. ecosse_011172

    henley

    Joined:
    Nov 13, 2006
    Messages:
    40
    Likes Received:
    0
    If it is a ground loop then try attaching the ground wire from your turntable to different components and the use more cable to further the ground path. Connect from amp to other electronics in different patterns. It's trial end error to see which resolves the issue but you should get there in the end.

    However, a ground loop is seldom evidenced by noise generated from external switches. If this is the case you may be better oiff with a mains conditioner.
     
    henley, Nov 13, 2008
    #11
  12. ecosse_011172

    ecosse_011172

    Joined:
    Dec 6, 2007
    Messages:
    20
    Likes Received:
    0
    Thanks a lot.
    I'll see how I get on when I eventually get my amp back.
     
    ecosse_011172, Nov 17, 2008
    #12
  13. ecosse_011172

    Fen Dancer Two left feet

    Joined:
    Sep 7, 2004
    Messages:
    133
    Likes Received:
    0
    Location:
    Rutland
    You can try moving your motor power supply as far from your phono as lead length will allow, or get your phono stage away from all other toroidal power supplies.
     
    Fen Dancer, Nov 17, 2008
    #13
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.