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Help me get rid of the HUM!!!!

Discussion in 'Effects [BG]' started by Trevorus, Oct 26, 2005.

  1. Trevorus


    Oct 18, 2002
    Urbana, IL
    When I use my sansamp, it is nearly noiseless, either plugged in, or on battery. But when I use my danelectro effects on the same circuit, they tend to emit a noticeable amount of hum. Does anyone know of a good cure for this? I use a daisy chain adapter cable.
  2. Hum/buzz can be caused by all sorts of things.

    Is it a low hum, or a a high pitched hiss/buzz? Does it change when you turn in different directions? Does it matter whether or not the bass is plugged in?

    There's always things like tv's, fluorescent/neon lights, etc.

    Some effects are noisy, and they introduce noise which is then amplified by other effects. Not knowing what your other effects are, I can't say.

    Have you experimented with the order of the effects - does that make a difference? If one of them is a compressor, you might want it first in line, since it will result in quieter parts (e.g., noise) becoming louder.

    If more than one component in your system plugs in with a 3-prong plug, you could have a "ground loop". I won't go into trying to explain the specifics of that here. You can find plenty around the net if you are interested.

    I noticed a hum intermittently with my gear. I use a rack mount compressor, but it is just sitting on top of the amp. Sometimes I get a terrible loud hum, other times it's quiet. I just noticed the other day that sometimes the chassis of the compressor touches metal screws in the top of the amp head. When it touches, silence, when it does not, HUM. Since it is just lying there, sometimes it was touching the screws, and sometimes not, explaining why the hum was not always present.

    A ground loop in action. I confirmed it by putting one of those ground defeating adapters on the compressor's plug, and *poof* the hum was gone. This defeats the safety purpose of the plug however, so it is not a good idea to do permanently.

    I am going to run a wire between the amp chassis and the compressor chassis to give a better connection than just having the compressor chassis occasionally touch a screw.
  3. psi


    Mar 11, 2005
    New Jersey
    Boss NS-2 supposedly does a great job of cancelling hum. Never used it though.
  4. LavendarSunrise


    Oct 5, 2005
    Also, to get rid of ground loop hum in an electronically safe way, you can disconnect the ground from the jack at ONE end of the input and output cables. This way, the grounds will not be connected between the compressor and your pre or power amps. The compressor will still be grounded through the power outlet. Of course, this will only work if you are using balanced cables, however.
  5. The boss NS-2 does a great job. It cancel hums, hisses and any other unwanted noise. it should work great for you.
  6. Aj*


    Jun 14, 2005
    West Yorkshire, UK
    Yeah a noisegate would probably be a good idea, I've found them very discreet yet effective when I've tested them.
  7. Joe P

    Joe P

    Jul 15, 2004
    Milwaukee, WI
    The NS-2 is super-duper, and I'd recommend it to anybody, for sure - but by all means fix the hum problem at the source, if you can!

    Perform some of the troubleshooting procedures suggested here, and post back. We'll try to fix it.

    THEN get an NS-2. Those things are the greatest, especially if you use compression or distortion.. or BOTH, like me.

  8. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    First, telescoping the ground only works if the audio ground has more than one connection to common ground. This isn't the case when using pedals.

    Second, you don't have to have a stereo/balanced cable to do this. You can use stereo cable with the shield telescoped, but that is different from lifting the ground totally at one end to eliminate a ground loop.

    Third, you should eliminate as much hum as possible before using a gate or noise suppressor.

    Last, I would suspect your daisy chain power supply, especially with cheap Danolectro pedals. Try running them off battery and see if the hum goes away/lessens.
  9. johans

    johans G.U.I - Groovin' under influence

    Oct 28, 2004
    the Bay Area, CA
    try this

    ISP Decimator

    way better than boss ns-2
  10. Joe P

    Joe P

    Jul 15, 2004
    Milwaukee, WI
    I'm tellin' you, Man - That NS-2 works VERY well, and has a mode of operation much like ISP's Pro-rack unit, where it senses the instrument itself seperately from the noisy stuff it's gating (hence the NS-2's send/return loop). Now granted the Pro rack has a dynamic filter, which is a way good-way to go, but the NS-2 in practical use - even with compression AND fuzz - Works very nearly perfectly.

    ..For clean playing, I mean.

  11. Dugz Ink

    Dugz Ink

    Oct 23, 2005
    That's the least expensive thing you can try, and the best place to start. By eliminating the power converter(s), you eliminate the possibility of introducing any "roll" or hum... which can be created by the cheap wall-warts.

    I'm not syaing there's anything wrong with the NS-2, but eliminating the creation of noise is better than trying to reduce the noise after it has been introduced into the audio.
  12. Trevorus


    Oct 18, 2002
    Urbana, IL
    The danelectros definitely hum when plugged in. They don't when they're not. I suspect wither a noisy input line on the plug in. When daisy chaining my tuner and sansamp, I have no noise problems. But when I plug in the compressor, it starts humming. When I run all but the compressor hooked up to power, but all in the chain, it's quiet again.
  13. Tritone

    Tritone Supporting Member

    Jan 24, 2002
    Santee, America
  14. FunkyLemz

    FunkyLemz Supporting Member

    Oct 17, 2005
    Los Angeles, CA
    I agree with the guys on the noise gate. You can pick up a rackmount compressor/noise gate/limiter in one. Some reviews say that some products tend to click when used with bass so do your research (if this is even an option). If not the boss pedal may work great too.
  15. Two things; either you have a ground loop problem, or you're overloading your wall wart.

    The later is easier to deal with, so we'll start there. What happens is you try to draw a lot of current and the supply starts to work to it's limits. The DC rail suddenly gets what's called an AC ripple voltage. This can manifest itself as an audible hum at the same frequency as the AC mains.

    A couple of things to try:

    First, if you have one, try a larger current rated wall wart.

    Or, just to check it out, here's what I would do first. Connect all of your effects pedals to the daisy chain and power them up (ie; insert a cable into the input jack.) Then, only connect one pedal at a time into the audio signal path and try each one in turn to see if it's one or all pedals that are humming. This will load the power supply to the maximum required by all of your pedals, but by only connecting one at a time into the audio path you lessen the chance of ground loops.

    Despite what some might say, ground loops absolutely can occur in unbalanced signal paths, and they absolutely can occur between effects pedals. If you're really serious about dealing with ground loops, there's only one solution I can suggest. The Spyder power supply at Geofex.

    Beware that some solutions to the ground loop problem are dangerous and many are useless... even worse, some are useless AND dangerous! I would not be surprised to find that some people have been killed trying to subvert a ground loop problem the wrong way. DON'T BE A DARWIN AWARDEE! DON'T MESS WITH MAINS POWER CONNECTORS!

    The safest way to check for ground loops is this; first, eliminate power supply overloading as a possibility. Then, hook everything up so you're getting the hum. Then, simply, disconnect power and run everything on batterys. If the hum is gone, and you're sure it's not the power supply ripple, then chances are you have a ground loop.

    You may wish to disconnect signal cable grounds as others have suggested, but do make sure that there's still a path from your guitar to ground!

    I would go one step further and say it's NEVER a good idea to do it EVER!

    Just to clarify, the NS-2 cancels nothing. It gates audio, great for that quiet passage where you're not playing or in between songs, but that's just about it.


    Effects pedals commonly have three ground connections; input jack, DC power jack and (via a metal chassis) the output jack. It only takes two to make a ground loop.