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Thread: Buzzing and Power Supply (Pedal board question)

  1. #1
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    Default Buzzing and Power Supply (Pedal board question)

    Greetings all,

    Some time ago, some of you guys educated me a bit about the effect of power lines, grounds and power supplies on the buzzing noises that pedal boards can generate.

    This morning I read a post on another site stating that swapping out the power supply can help improve the buzzing situation. There we no details and I don't have any understanding of the science involved.

    I am using a BOSS BCB-60 (and I may buy a P1000 in the future). However, I get pretty bad buzzing from some of the pedals (any thing that adds gain) and I also get an intermittent buzzing that is a bit stronger - regardless of which pedals I am using.

    My amp is a very cheap "Success MGD40"- very poor quality but it gets the job done for now.

    I have tried swapping all the cables but that has had no effect.

    Is there any hope that buying a different type of power supply might solve this problem?

    Many thanks,

    Peter

  2. #2
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    Default Re: Buzzing and Power Supply (Pedal board question)

    I experienced some similar issues a couple months ago while finishing up my electric guitar pedalboard. I got buzzing and some other random unwanted noise while using a one-spot type power supply. After trying everything on the board and rearranging, taking pedals out, etc, I ordered a Voodoo Labs Pedal Power II. Problem solved.

    It is a truly great, solid product in my opinion. They are however a bit pricy. So before you decide to buy a different power supply, go about making sure it is the current power supply that is causing problems. What I did was I put all of the noisier pedals on regular 9V batteries to see if they kept buzzing. Try this and if they stop, you know you have a power supply issue. Otherwise, you may want to look into replacing the pedal.

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  4. #3
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    Default Re: Buzzing and Power Supply (Pedal board question)

    Great suggestion - thanks - I am charging some 9v's as I type this.

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    Default Re: Buzzing and Power Supply (Pedal board question)

    OK - So I have tested the theory and gotten the following results.

    1) The CS-2 always buzzes, no matter what I do. However the buzz is more distinct when plugged into the power of the board.

    2) Both of my distortion pedals produce very little buzz when they are activated on their own and the noise is even less if use batteries.

    3) If I use the CS-2 in combination with any of my distortion pedals the problem is exacerbated.

    4) Touching my strings lowers the buzzing - removing my hands from the instrument increases the buzzing.

    5) Adjusting the tone, volume (of course) and the push pull (humbucker or no) nob effects the tonality of the buzz but doesn't get rid of it.

    Any suggestions would be appreciated!

  6. #5
    Registered User jambalaya's Avatar
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    Default Re: Buzzing and Power Supply (Pedal board question)

    sounds like there might be a short in the wiring of the instrument somewhere. that's what #4 would indicate anyways.

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    Registered User Tom Wright's Avatar
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    Default Re: Buzzing and Power Supply (Pedal board question)

    I think there are multiple issues here. The instrument may be less-than-excellently shielded--at least the metal parts are grounded, which is why it does what it should--get quieter when you hold it.

    A compressor will of course raise the gain on all inputs, so when engaged it will increase hum if that is present. You don't say clearly but I presume you tried the CS-2 with a battery?

    I had hum problems with a Boss Digital Delay that hated sharing with another pedal on a single AC adapter. The pedals need enough current, I guess, and any digital processing they do is power-hungry.

    I am betting you have a combination of hum antenna (mando), gain boost increasing hum (compression) and inadequate power supply allowing hum from pedals themselves.

    Even humbucking pickups can allow some hum if the coils are not perfectly matched. And your environment may be particularly rich with AC fields broadcasting into your instrument's wiring. It also may be that the Boss pedal power filtering doesn't like trying to smooth Chinese 50Hz instead of 60 Hz.
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  8. #7

    Default Re: Buzzing and Power Supply (Pedal board question)

    Quote Originally Posted by jambalaya View Post
    sounds like there might be a short in the wiring of the instrument somewhere. that's what #4 would indicate anyways.
    I'm struggling with a similar problem, but I have all of my pedals on a voodoo laps power supply. I was under the impression that #4 was strongly indicating a ground issue, but not sure. I have the same issue even without the pedals, so I guess it's instrument, amp, or wall outlet the amp is plugged into.

  9. #8

    Default Re: Buzzing and Power Supply (Pedal board question)

    #4 - The best way to determine if there is a grounding problem with the instrument is to use a multimeter - one probe on the output jack ground and the other to the strings.

    But there is a caveat - you may get a good reading but still have a problem. That can be indicative of a "ground loop". Most instrument schematics show taking grounds to the pot casings, but this is often the source of a ground loop heard as a hum. The only sure way to eliminate them is using a "star ground" schema - i.e. running all grounds to a single grounding point.

    Yet another issue that can cause these problems is when you have a shielded electronics cavity but the shielding isn't taken to ground properly. That tends to be more of a static sound when strings are touched/untouched.

    As noted above, compressors are designed to level out the amplitude of a signal by bringing quiet parts up and not allowing loud parts past a certain threshold. Noise is usually "quiet" but becomes very noticeable through a compressor since it's made louder.

    Not all buildings are properly wired. Some older buildings I've been in don't have proper grounds but the owners changed out the 2 prong outlets to 3 making it appear so. In this case I found running a wire with alligator clips from a ground/chassis point on the amp to something in the building you know to be grounded, like a radiator or water pipe, will solve the issue.

    Have patience - these issues are normal and take a bit of time to sort out.
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