1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Phono Amp Misery!!

Discussion in 'TAG McLaren Audio Owners' Forum' started by Burgy100, Feb 22, 2005.

  1. Burgy100

    Burgy100
    Standard Member

    Joined:
    Apr 20, 2004
    Messages:
    137
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Bedfordshire, England
    Ratings:
    +2
    I have recently bought a cheap phono amp off E-Bay, in an effort to listen to some of my large black discs. What a mistake, I thought it would be a simple process of using one of the spare analogue inputs and plug and go. Unfortunately it suffered from severe mains hum and I spent 3 hours trying to find the source.

    As I remember many years ago the deck/arm needed to be earthed and there is no means on the phono amp to ground the LP deck. Managed to cure it (almost) by attaching the earth to one of the phono sockets. E-mailed the bloke I bought the amp from to say 'is this a design fault?' and his response was either to hook it up (the earth) to my AV32 or attach the earth to the earth on the deck plug socket!! Hope I am making sense and that should cure the problem. I have yet to try this.

    My question is 'Is he correct will that cure it, or is he talking pants', I thought you have to earth the phono amp to close the loop. Todays receivers/pr-amps have a grounding earth already on them, but surely the token phono amp is already within the unit.

    Before you ask the deck is an Ariston RD80 with a SME 3s arm.

    Your guidence would be most appreciated
     
  2. roversd1

    roversd1
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    If you deck has an earth lead, connect this to specific earth connection on your equipment.

    The majority of record players need earthing.
     
  3. Burgy100

    Burgy100
    Standard Member

    Joined:
    Apr 20, 2004
    Messages:
    137
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Bedfordshire, England
    Ratings:
    +2
    Hi There,

    Thanks for the quick response. My AV32 has no means of connecting Arm earth and the phono amp has no earth terminal on it!! I believe you should connect the earth to the phono amp and not my AV32. As I said, seems like i made a mistake and as the saying goes 'you get wait you pay for!! :suicide:
     
  4. laalves

    laalves
    Active Member

    Joined:
    Feb 6, 2005
    Messages:
    493
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    21
    Location:
    Cascais
    Ratings:
    +8
    Try this experiment: remove your TV antenna cable from its socket and see if the "hum" goes away. If it does, that's that. That's also the problem I had.

    The cure: stop seeing TV and being a couch potato.....

    No really, just kidding. You can cure it the way I did: buy a Jensen transformer, or similar (I even made one, before I opted for the Jensen product, which yelded much better results). Before that, I replaced my RQ970BX phonostage transformer with a Nuvotem toroidal, installed a IEC mains filter in the Rotel, shielded the inside of the Rotel casing with copper EMI shielding foil. The result: quite an improvement in dynamics, actually, but the same "hum".....

    It will also help to reduce any grain that you may end up having in the TV image (as happened to me) if you also replace the cheapy kind of antenna cable with a nice QED Qunnex one. This is a very good product indeed. Very nice shielding against EMI. Before I tried this cable, I couldn't almost watch any TV channel using my PCTVPro PC telly tuner board, since there was so much grain and interference. With the QED cable, the interference and grain went away, just like that.

    Luis
     
  5. roversd1

    roversd1
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Thats all a bit complicated for this guy as that is more to do with a ground loop rather than his simple earthing issue.-


    Its not really anything to do with cheap equipment. All you have to do as you have discovered allready, is to connect the record player's earth lead to the AV32R or the power amp chassis.

    The phono amp you've bought is a simple low voltage amplifier turning the very low output of you record player's cartridge into a recogniseable voltage for the AV32R.

    You should find that the hum disapears or at least gets very quiet by connecting the record players / tone arm's earth lead to the chassis of the phono stage or the AV32R chassis. Any external rear panel screw can act as a connector, just as you would have found on a reciever or integrated amplifier.

    You wont do any harm to yourself or the equipment as the AV32R is double insulated - all exposed metalwork is separated from the conductors by two layers of insulation, so that the metalwork cannot become live and zap your gonads

    :0
     
  6. Burgy100

    Burgy100
    Standard Member

    Joined:
    Apr 20, 2004
    Messages:
    137
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Bedfordshire, England
    Ratings:
    +2
    Hi,

    Many thanks for that. Laaves, a wee bit to much for me, just want to listen to music!! Attaching the earth lead to the phono amp does not cure it completely, there still is some background hum, I presume attaching the earth lead to the AV32 will be the same. Best way forward iI suppose is to buy proper phono amp, rather than a cheap one.
     
  7. Kenny Glasgow

    Kenny Glasgow
    Well-known Member

    Joined:
    Apr 1, 2004
    Messages:
    3,346
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Livingston, Scotland
    Ratings:
    +225
    Burgy

    If you can't find a PPA try and get a hold of an Audiolab 8000A or C
     
  8. Burgy100

    Burgy100
    Standard Member

    Joined:
    Apr 20, 2004
    Messages:
    137
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Bedfordshire, England
    Ratings:
    +2
    Hi Kenny,

    I'm sniffing around for a PPA right now!!

    Steve
     
  9. roversd1

    roversd1
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    There are lots of good, low cost phona amps, I used a NAD for years, retails for about £30.
     
  10. Burgy100

    Burgy100
    Standard Member

    Joined:
    Apr 20, 2004
    Messages:
    137
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Bedfordshire, England
    Ratings:
    +2
    Trouble is I bought a cheap phono amp off E-bay, regretting parting with my dosh albeit for seventeen quid. Its the old saying 'you get what you pay for'

    Steve
     
  11. roversd1

    roversd1
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0

Share This Page

Loading...