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Annoying effects hum

Discussion in 'Effects [BG]' started by epic576, Oct 13, 2013.


  1. epic576

    epic576

    Jan 17, 2013
    Gloucester UK
    Greetings once again Talkbass brethren,

    Once again I come to you to ask for advice,

    My pedal board as it stands is thus -

    Bass - (Westone Thunder 1A)

    Korg Pitchblack
    Bad Monkey
    Morpheus Droptune
    Ibanez WD7
    Sansamp BDDI

    Amp - (Laney RB1)

    With this set up as it says in the title, I'm getting a constant humming which is increaed when I use either the wah, Sansamp or Morpheus.


    I seem to think my chain is in its most logical order but not too sure. As I have one more space on my board would a noise supressor be a worthwhile investment?

    Any advice would be appreciated

    Cheers

    AJ
     
  2. one of my adaptors creates a hum, and, extremely unexpectedly, my Moogerfooger Analog Delay when not in bypass mode creates an unbearable hum that would drive anybody crazy. it's new, and i never thought that the most expensive Moog pedal would give me any class of problem. fortunately, Sweetwater is willing to replace it and ship it back to them for free- as they should, really.

    sorry i have no advice, just thought id chime in that you are not alone.
     
  3. Rafescow

    Rafescow

    Oct 21, 2009
    are you daisy-chaining your pedals to power them up? many times this kind of power supply occasionates undesirable hum (that's due to pedals' phase differences, if i'm not wrong... i'm no expert though haha)
     
  4. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    The power supply type is the usual first thing to suspect and test. Does the hum go away if you power each pedal off its own separate wall wart or batteries?
     
  5. epic576

    epic576

    Jan 17, 2013
    Gloucester UK
    I'm using the Warwick Rockcase pedal packer gigboard.

    I think Rafescow is correct as it's basically a daisy chain in a box.

    To Bongomania, btw I'm a big fan of your compressor reviews, the hum is present even if all are turned off but only barely, still noticeable however.

    I haven't got separate wall warts and could try batteries in all but some are notorious for eating through 9V like nobodys business.
     
  6. If the hum is still around with the pedals off, try without your board entirely and see if maybe its the bass.

    Happened to me and had to get my electronics touched up a bit.
     
  7. RickenBoogie

    RickenBoogie

    Jul 22, 2007
    Dallas, TX
    Isolated power supply is the answer. It's an investment, but something like the Voodoo Labs Pedal Power plus is what you need.
     
  8. epic576

    epic576

    Jan 17, 2013
    Gloucester UK
    Seems the most logical solution. Hypothetically, would a noise suppressor i.e. NS-2 ISP Decimator make any difference at all?
     
  9. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Yes, it will make everything sound much worse. Solve the actual source of the noise rather than applying a bandaid. :)
     
  10. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Turning the pedals off is not actually a test of whether there's a ground loop. As far as eating batteries, you only need the batteries to last a few minutes while you do the test.
     
  11. epic576

    epic576

    Jan 17, 2013
    Gloucester UK
    I'll see what I can do, I've taken the Sansamp out the chain completely and nearly no hum whatsoever. Is the BDDI just a noisy pedal?
     
  12. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Not with hum, no. But it might turn out to be incompatible with daisy-chaining power with one or more of your other pedals.
     
  13. So if I'm getting a hum using a OneSpot, there's a good change that's the cause...?
     
  14. RickenBoogie

    RickenBoogie

    Jul 22, 2007
    Dallas, TX
    Yes. Isolated power solves most of these issues.
     
  15. tech21nyc

    tech21nyc Commercial User

    Aug 17, 2010
    Manufacturer: Tech 21
    We don't recommend using our pedals with these power supplies. Sometimes they work and sometimes you have issues. Isolated power supply is the way to go. When you use one of these power supplies, you tie the grounds of all your effects together which is not a good idea in an audio application. Secondly these supplies have an oscillator which has a frequency as do many digital pedals. If these two frequencies are different they can cause problems and leak into the audio chain.

    Any pedal that is in you chain that is increasing gain or distortion will amplify the problem further.
     
  16. For a technical explanation by somebody who makes electronics, that's rather an inept response. The power supplies have a frequency as do many digital pedals. If you mean the switch mode supply then proper design prevents harmonics getting onto the DC line with decent low pass filtering. Cheap or just poorly designed switch mode PSUs are frequently responsible for all sorts of interference (as in nearly all laptop PSUs). You don't need two devices to get PSU noise. Two rubbish PSUs can only make it worse.
     
  17. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Sorry but you are kind of missing the boat here. The oscillations from the PSU leak into the audio path wherever there is a point that the path of least resistance can be a jump between the audio and ground lines. Some pedals are much more vulnerable to this than others, due to the design of their ground schemes, whether they tie to the chassis, whether they have metal-bodied jacks, whether they take a +tip DC plug, whether their ground is "floating", and a variety of other factors.

    All commonly-available switch-mode supplies leak clock noise into their ground path. So it makes no sense to talk about "rubbish" PSU's. If it was a cheap and easy thing to prevent leakage, surely that would be a common feature--but it is not.

    Additionally, the main problem is not the clock noise at all, but the tying of dissimilar ground planes together. This creates a potential, and the potential has to go somewhere, and as often as not it leaks into the audio path. We hear it as noise.

    The fault is in the combining of two or more pedals with slightly dissimilar ground schemes, and then typing those grounds together. That's why isolating the grounds solves such a large percentage of this type of problem.
     
  18. thanks for the detailed explanation! i got the gist of the problem many years ago but never heard it articulated so well.
     

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