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Hartke LH1000 hiss and pops / grounding issue?

Discussion in 'Amps [BG]' started by Metalian, Dec 2, 2013.


  1. Metalian

    Metalian

    Joined:
    Nov 1, 2010
    Location:
    Cambridge, UK
    Hiya,
    I've got a Hartke LH1000 with HX410 and HX115 rig. I've had this setup for the last 3-4 years and I am super happy with it. Recently however I've noticed small issue which can be quite serious in the long run.
    Whenever I touch any metal component on my bass (bridge, strings, control knobs) the speaker pops.
    First I suspected bad grounding on my bass, but it happens to all of them and I have rewired on myself just to make sure there's a good solid ground.
    Then I discovered that amp on its own also produces POPS to the speaker when I touch the metal rack that is mounted to.
    taken out of the rack it also pops every time I touch input or any metal unpainted part.
    I have tried brand new mains lead to make sure it is ok and eliminated everything else in the chain leaving the LH1000 alone...and yes, it still pops. It sounds like static pops and overtime when it gathers it will pop quite loudly.
    When connected with a bass it will generate quite annoying hiss/buzzing noise, that goes away as soon as I touch metal part, like bridge or the strings, which always give me that unhealthy 'POP' noise.

    I'm guessing that one of the internal components may given up over the time, but I would really appreciate your opinion.
    Many thanks in advance.
    Mackie, Cambridge, UK.
     
  2. Matthijs

    Matthijs

    Joined:
    Jul 3, 2006
    Location:
    Amsterdam
    Doest it hum and pop in all locations, or only in your house?
     
  3. ejmy

    ejmy

    Joined:
    Nov 30, 2008
    And no ground lift on that model, too bad. Maybe start by trying a different power cord. It's removable like a PC. Or plug an adaptor without a ground at the end so you can switch sides at the power outlet.
     
  4. David Jayne

    David Jayne

    Joined:
    Jan 16, 2006
    Location:
    Brookfield, CT
    No, don't do that. It's potentially hazardous.
    Sounds like a simple case of static. Is it really dry in your location? Carpeted floor?
     
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  6. ejmy

    ejmy

    Joined:
    Nov 30, 2008
    Yes you are right, it could be potentially hazardous. I meant to try it to narrow down the problem.
     
  7. Metalian

    Metalian

    Joined:
    Nov 1, 2010
    Location:
    Cambridge, UK
    Thanks for your messages.
    It's not only at my house. I have tried it on a different locations, two different rehearsal rooms, studio and few gig venues - all the same issue.

    I also tried brand new as well as known working mains lead, so I'm sure the 'earth/ground' is there...problem persists.

    You can hear this hum from the speakers, until you touch any metal component in the loop - like bridge or strings, then you can hear a little POP, and silent, until you let go of that metal part again.
    Forgot to mention that I only use passive pickups, and the HF horn is turned off.

    ?
     
  8. Metalian

    Metalian

    Joined:
    Nov 1, 2010
    Location:
    Cambridge, UK
  9. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    Tried a different bass? Usually, it means that the ground is loose in the bass when you can touch the strings and it goes away. Since it does it without a bass, that may not be the case here, but worth a shot just to eliminate it from the equation. I'd also try replacing the tube just to eliminate it as a culprit as well.

    Anyway, I'd call Hartke and see what they think.
     
  10. David Jayne

    David Jayne

    Joined:
    Jan 16, 2006
    Location:
    Brookfield, CT
    Gonna have to go ahead and disagree with you, Jim. It means the ground IS functioning.
     
  11. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    Huh? It would be functioning if it's quiet whether you touch the strings or not.
     
  12. David Jayne

    David Jayne

    Joined:
    Jan 16, 2006
    Location:
    Brookfield, CT
    The fact that it goes quiet when the strings are touched means that the ground must be working, otherwise there would be no change. This is much more likely to be a shielding problem.
     
  13. Metalian

    Metalian

    Joined:
    Nov 1, 2010
    Location:
    Cambridge, UK
    Thanks for that,
    Yes, I have tried different bass, in fact i have tried 5 different basses and a guitar too, all the same case. I even rewired my bass myself paying extra attention to the ground from bridge and pickups - issue is still there. So I narrow it down to the amp head itself.

    dmusic148 - can you please explain the shielding problem a bit more? Is this something I could do, or is it a service only item?

    I think I will have to call Hartke, as this is bugging me more and more every day.

    Any other suggestions most appreciated!
     
  14. David Jayne

    David Jayne

    Joined:
    Jan 16, 2006
    Location:
    Brookfield, CT
    I was talking about shielding within your bass. But if several different ones exhibit the problem it really can't be them. You should verify that the ground pin on your power cord is functioning. There's a chance that it isn't, and this MAY contribute to the problem.
     
  15. Metalian

    Metalian

    Joined:
    Nov 1, 2010
    Location:
    Cambridge, UK
    I tried brand new, as well as several other known working mains leads. all the same, it's like the issue is inside the amp itself.
    I'm guessing nobody had this issue before.
    Better call Hartke...
     
  16. ProdigalBassman

    ProdigalBassman

    Joined:
    Mar 22, 2012
    "A chain is only as strong as its weakest link"
    Just to cover basics, so easily overlooked: Have you been using the same instrument cord with all these basses & guitars? If so, try another, quality cord. I find it interesting that this problem has arisen after several years using the same(?) bass / amp combination. That suggests it's not a question of shielding as that would've always been an issue. It sounds as though something has deteriorated. One amp web site (I forget which) reminds us to periodically clean the input jack on the amp (unplugged!) which can accumulate dust / dirt or corrode.

    I have no idea if any of this is your problem, but I'm big on ruling out the simple solutions before going on to expensive ones :)

    Let us know how this turns out. I've been thinking of getting an LH1000 myself.

    Joe
     
  17. David Jayne

    David Jayne

    Joined:
    Jan 16, 2006
    Location:
    Brookfield, CT
    When I said 'verify the ground is working' I meant all the way to instrument ground. Get a meter and check continuity between the ground lug of the power cord and the sleeve of instrument cord.
     
  18. Metalian

    Metalian

    Joined:
    Nov 1, 2010
    Location:
    Cambridge, UK
    Hey and thanks for more input. I haven't called Hartke yet, in fact I haven't used that rig since xmas until last week. And yap, the issue didn't just magically disappeared ;)
    Yes, I ruled out all the simple obvious matters - like different bass, and a good, known working lead. In fact I am now pretty sure the problem is within my amp, as this unit alone causing issues with completely different setup. And all my other gear works fine without the LH1000.
    I was thinking to temporary bypass the issue by 'wiring' the chassis of the amp to ground, but I am a little reluctant of doing this, as it won't really fix it...it will just cover the noise.
    Opinions?
     
  19. David Jayne

    David Jayne

    Joined:
    Jan 16, 2006
    Location:
    Brookfield, CT
    The chassis is supposed to be wired to ground already. The test I asked you to perform will prove or disprove this.
     

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