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Ground hum driving me crazy when using pedal board (6 boxes), what to do?

Discussion in 'Effects [BG]' started by RedMoses, Aug 3, 2012.

  1. RedMoses


    Jul 4, 2012
    Sup TB,

    Ive been playing with my band Chromatropic for since December, over the months ive crafted a sound and put together a pedal board as ideas for tones came about. It started with a Comp, Preamp and tuner, then Dirt, Octve and finally an Env Filter.

    I played a first session with the filter on Monday and it sounded great, come Wed i kept getting disrupted by ground Buzz, i mean LOUD and annoying, during quiet passages its unbearable. I thought it was my Bass because when i touch the knobs or the bridge the Buzz goes away, went to my tech the next day, plugged in to show em what im talking about and the passive P/J Bass was dead quiet, ***?:meh:

    I was told it may be the power in our building and i also thought it may be one of the pedals, i tried all different combos and when i go throug the board, i get the Buzz! I even tried plugging the power strip into different outlets and still no dice.

    I have a 1 spot power daisy chain for 5 pedals and the Tone bone pre amp has its own wall wart, both are 2 prong, so im thinking perhaps this may be the issue, although im plugging into a grounded power strip, im still getting not grounded.

    What do you guys do to kill the hum? :help: Is there a power conditioner or something for pedal boards that i should look into? We are playing a big festival tomorrow and i cant be Buzzing the entire set, im going to Guitar center to pick up some last min items and i hope i can pick up a solution.

  2. EricssonB


    Apr 5, 2011
    CoSpgs, CO.
    Something something something I read a while back about DC voltage reference points being relative to each other, not to zero, causing hum. Something like that.

    Solution was to isolate it to a single pedal (or pair, actually) and possibly throwing the problem onto battery power or finding an isolated power supply and dividing it -- or just eliminating the problem pedal as you won't ever be able to fix it.

    Not terribly specific, or specific at all, but it's all I've got.


    *feeling English*
  3. alec


    Feb 13, 2000
    Perth, Australia
    Cool board!
    I'd start by just plugging in one pedal (to both the power and the signal path) and see if that causes buzz. If not, add pedals one at a time and see where things go wrong.
    If it's a power issue, using a power supply with isolated grounds (like Voodoo Labs PP2) could be the answer.
  4. dmrogers

    dmrogers Supporting Member

    Jan 26, 2005
    Eastman, GA
    I recently ran into something similiar on my guitar pedalboard. I had purchased a couple of new pedals. I used a new wall wart on one of the pedals and got hum. I tried one pedal at a time to find the offender. Switched to battery and no hum.

    To permanently fix the problem, I tossed the offending wall wart and got the proper one for the pedal. Now I am using a 1Spot for most of the pedals and don't have the problem.

    So yes, the problem is most probably in your power somewhere. Try one pedal at a time in the chain until you find the problem.

    Good luck!
  5. pantherairsoft


    Apr 22, 2009
    Derby, UK
    You don't want to buy something to try and fix it you want to get to the bottom of the cause and remove it.

    1stly hoe many buildings/locations have you tried it in and experienced the noise in, so far your post makes it sound as though you've only hear it at practise? If so, have you tried turning off stuff in the building like strip lights or even the fridge? it could be the building is badly wired and it doesn't like your combination of grounds - I experienced this in an old building we used to rehearse in. Drove me mad and it was the wiring in the building all along.

    if you have heard it in more than one place, set up your stuff so you can hear the noise then remove one pedal at a time or start with one pedal and keep adding them to see if a particular one is causing it.

    If this gives no joy then do the same with patch and instrument cables, changing one at a time. Start with the lead from bass to board, then the first patch lead, then the next etc etc to see if one is causing it.

    After that try and borrow a different power supply form a friend, fellow musican etc... one that is a different brand ideally. Also try powering any pedals that work on battery by battery - this may identify if its the supply itself or the pedals reacting to the supply.

    My gut feeling is the building or something in the building causing you issues.
  6. RedMoses


    Jul 4, 2012
    I played a gig last week and i din't notice the hum(without the Env Filter), we also rehearsed on MOnday (with Env Filter) and i dint notice the hum...

    I tried isolating one pedal at a time and still got the hum! Gotta give batteries a shot but im worried about them craping out during a set, these pedals dont last too long on them. Chances are its the building, its a VERY old brewery from 1857 and was rewired when they converted to rehearsal spaces. I wont really have a chance to test my setup until sound check at the festival....

    I had hoped you guys would have a magic box solution i could buy, any of you guys using a pedal power conditioning solution of some sort? i guess the best bet is to buy a bunch of batteries and give that a shot.

    I could try the Voodoo Labs PP2 but Dang, $170! I suppose if it will work its worth it...
  7. pantherairsoft


    Apr 22, 2009
    Derby, UK
    Don't go gigging with the batteries - use them in the location that gives you the noise to see if removing the power supply form the chain helps.

    If you have never had the problems at a gig, or in fact anywhere but the old building then my money is on the building and other than having it rewired at a silly expense there is nothing you can do.

    I had exactly the same problem in a building from around 1900 and for 3 months I had to rehearse with mains hum constantly.

    One last thing to check is the wiring in your bass - You mentioned there was a time when touching the bridge stopped the noise - so it was grounded though you - There is a 'slight chance' you have a loose ground wire in the bass which is moving sometimes it's connected and fine, other times it's moved off point and not grounding correctly. This is unlikely but worth checking for completions sake.

    I don't use power conditioning etc - we moved rehearsal room to somewhere never and newer and I've never had a problem at a gig.
  8. Koog

    Koog Supporting Member

    Dec 27, 2010
    Central Iowa USA
    Check for florescent lights and beer signs. They sometimes cause 60cycle hum through the PA or other amplification on stage.
  9. octaverazor


    Jun 3, 2009
    Houma, LA
    At our old rehearsal space we had considerable hum from a couple pieces of gear. It wasn't too bad so we learned to live with it. Then one day some one turned off the light switch in another room, hum was gone. Turn the light on, hum returns. My point is hum can come from the weirdest places.
  10. sunbeast

    sunbeast Supporting Member

    Jul 19, 2006
    Los Angeles, CA
    This- sort of :p When you touch the strings on your bass, you are actually grounding your body and NOT the opposite. Your bass itself is grounded through the wall outlet, but your body is like a big antenna for noise and interference from everything in the area. When you touch the strings or any other metal components on your bass that would be grounded via your instrument cable, you are then grounding your body and most/all of the noise that you are introducing to your pickups just by standing closely to them! This would explain why the problem is less noticeable depending on where you are- places with alot of potential noise sources nearby (computers, light faders, refrigerators, and many other electrical appliances) will tend to be much worse than fairly isolated practice spaces or venues. You can probably turn your body in certain ways to quiet the noise to some degree much like turning an old-school TV or radio antenna to get the best signal, except that in this case you are trying to find the weakest signal! If the buzz didn't go away when you touched your strings it would mean that there was likely a grounding problem in your bass (usually that the wire running from the bottom of your bridge was loose or disconnected), but since touching the strings makes it go away you know the bridge ground is doing its intended function.

    Since your pickups are picking up interference from your body, one big fix is to just shield the heck out of your bass, especially around the pickup and electrical cavities and make sure that all of this shielding is well grounded. This is still not necessarily a perfect solution in some extremely noisy places, but can make a huge difference- many factory basses have absolutely no electrical shielding installed, so magnetic pickups are sensitive also act like magnets for noise, and your body is like a big noise amplifier that is always sitting right next to them. If it only seems like a problem in a few locations and you don't have time to try extra shielding in your bass you can just make sure that you always have one hand on the strings even when not playing. There is even a product made for this purpose that is just a bracelet with a conductive wire that goes around the metal shaft of one of your basses control pots so that your body is always in contact with a ground point! You could make something similar very easily just using a length of wire attached anywhere on your body attached anywhere grounded on your bass (I've had to do this before in a few noisy home studios a few times so that I didn't accidentally take my hands off the strings in the middle of a recording and ruin the take with a nasty buzz).

    To test whether this is actually the culprit in your noise problem- does plugging straight into your amp with no effects affect the noise? It should be noted that touching the metal on most pedals or your amplifier will likely also ground your body through the wall circuit the same way that touching metal on your bass does.

    Good luck!
  11. RedMoses


    Jul 4, 2012
    I ended up getting the Vudoo Labs 2 Plus, took it to the practice space right before packing up for a gig AND to my relief things are quiet again! It was $165 solution but its piece of mind, its feel really dependable, that one spot was kinda rinky dink and would cut in and out if you touch the coupler area.

    Unfortunately the brick is too big to fit on my pedal board, but it dint feel akward set up right not to the board, it was all very tidy. I originally wanted the DUnlop Brick (pedal size $110) but it does not have isolated grounds.

    The pedals were clean and quiet at the gig.
  12. sunbeast

    sunbeast Supporting Member

    Jul 19, 2006
    Los Angeles, CA
    Yeah the Dunlop Brick is a rip off- I think they are essentially expecting people to assume its an isolated supply, when it is really no more than a 1 spot in a less convenient and much more expensive package...
    Glad you found a solution!
  13. monti2889


    Jul 19, 2012
    I had the same problem with a pedal, then I had realized the when I bought the pedal someone had installed the 9v battery, so when I plugged in the pedal to power, it became a little noisey. Also, you want to make sure you are plugging your amp and your pedals power supply into the same branch circuit, this will eliminate ground loop and phase interference.
  14. Shappo


    Apr 28, 2010
    Right on the money there. The studio at my uni has terrible power in one of the rooms, it made my friends board buzz insane.
  15. t77mackie


    Jun 13, 2012
    Wormtown, MA
    Have an electrician friend plug his multimeter and wiring checker into the receptacles. See what he says.

    Buy a Furman power conditioner.

    Get rid of the Envelope Filter (you don't really want that thing).

    Take the canolli...
  16. miiitch


    Nov 27, 2011
    just a bit of hijacking:

    got awful ground(?) hum as soon as i connect my pedal (12V AC tube drive), but ONLY at our rehearsal space.
    the owner´s not willing to have the electrics repaired (it´s a church, probably not enough money for that.)

    this gadget here:
    did not help.

    i just hope that the power supply i´ve been waiting for (2 months already -.-) solves the problem ... 8x9V DC plus 1x12V AC or DC, all isolated ... gonna inform you if i´ll ever get it
  17. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Unfortunately, odds are the problem is not about isolation in your case. It could be that the pedal is picking up ambient EMF from nearby power distribution (like a fuse box). Also, when the wall sockets are ungrounded, you can't make them grounded by adding some device in your rig. What you CAN do, however, is get a good length of copper wire (any kind), screw one end to the metal chassis of your amp or rack rails, and run the other end all the way to the nearest metal pipes (old plumbing or gas pipes, must be metal). Use conductive foil tape to attach the wire to the pipe. In most cases this will effectively ground your rig and it can sometimes eliminate hum.
  18. miiitch


    Nov 27, 2011
    i´m not too much into circuitry (or whatever the name is), but i´ll try connecting the pedal to the radiator, the only thing around that´s made of metal.
    if that´s going to solve the problem, i´m gonna build an altar for you, since it took about 100 "specialists" to end up with more noise than i started with.

    (we have a 12V battery pack here, 9Ah, both AC and DC out ... was trying to use it as a temporary power supply for testing, but it broke down some days before -.- )
  19. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    The pedal is grounded to the rest of your chain and the amp via the patch cords, so you don't actually need to attach the ground wire to the pedal itself. Some amps actually have a screw on the back panel, marked with a ground symbol, meant for this exact purpose. Otherwise, you can pick an item in your chain that has metal jacks, and partially unscrew the nut from one, and wrap the wire around the threaded part of the jack and tighten the nut back down.
  20. do the math on your pedals, chart the voltage & mA requirements, then go here.

    BBE supa charger & Trex Fuel Tank Jr are cheaper then the PP2+, but i'm not sure what your pedals demands are. from the look of it i'd keep the Tonebone on a wall wart & Fuel Tank Jr the rest, route them both into a fancy surge supressor power strip.

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