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Getting rid of hum in your rack

Discussion in 'Effects [BG]' started by millard, Dec 20, 2004.


  1. millard

    millard

    Jul 27, 2004
    SoCal
    Has anyone tried both balanced and unbalanced 1/4" jacks between their components to see if it drops that noise that happens when nothing is happening? I can kill most of that noise with a gate, but the noise gets back through again when you play. Practicing a relatively low volumes in the house, that noise is annoying.

    Going to balanced connectors is all I can think of at the moment to help with that, but it ain't cheap to buy all of those cables (just to find out it didn't do any good). Right now I'm just using the LiveWire connectors that used to be in my pedal board. Not that it was noise free either (but I never expected it to be).

    Thanks...Millard
     
  2. Two things to consider: Do you use bushings between your screws, gear, and rack rails? Most racks come with teflon or plastic bushings, or you can buy them in a music store's pro audio section. Sometimes ground loops are caused through a rack's metal parts. Secondly, do you have flourescent lights going? You'll get hum there too. Third, do you have a television on in the same room or same circuit when your practicing? Lastly, do you have all the rack gear where it should be in your signal chain? Line vs. Instrument level in the effects loop or before the preamp? All this can add unwanted noise.
     
  3. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    Millard,

    Balanced cables will only make a difference if all the gear you're using has balanced ins and outs. Most guitar/bass gear doesn't.

    Chasing noise can be a pain, but you have to start methodically. Turn on just your amp, or just your pre and power amp. Bass > amp > speaker. Is that noisy? Then add one effect/processor at a time until you find a noise offender.

    In addition to Mo's advice, make sure you're describing what you're hearing. Is it hum or is it hiss? Different problems with different causes and different solutions.
     
  4. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    Does the noise go away if you don't have an instrument plugged in? If so, you may need to shield your instrument.

    Computer monitors, TV's, light dimmers, refrigerators, washers, dryers, and many other things can cause noise. Plugging in to a different outlet can sometimes diagnose these problems.

    You may have a ground loop problem. The teflon washers are insufficient to isolate the boxes from the rack. They do sell isolation hardware at online music stores.
     
  5. millard

    millard

    Jul 27, 2004
    SoCal
    You may be onto something with the isolating the boxes part. I remember holding one end of a patch cable while looking for the right place to plug it in and resting my hand on the power amp -- and hearing the hum drop.

    Why won't a nice plastic washer help? I noticed that the dbx gear game with washers. The circuit in use is one of the quieter ones in the room (found that out already).

    I did do some component checking and I think I was getting a fair amount of noise just going into and out of the Sansamp RBI unit. My bass is whisper quite going straight to my combo amp.

    Thanks all for your suggestions...Millard
     
  6. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    What is everything in the rack plugged into?
     
  7. millard

    millard

    Jul 27, 2004
    SoCal
    I'll list the whole thing in case anyone recognizes problem components:

    Furman PL-PLUS II power conditioner
    Sabine RT-7000 tuner
    dbx 266XL compressor/gate
    Sansamp RBI
    TC M300 Dual Effects processor

    Currently hooked together with LiveWire unbalanced patch cables. Components are screwed directly to rack (something I will fix as part of the problem solving process).

    That's plugged into the quietest outlet in the room. When my GK Backline 115 is in use, the thing makes almost no noise at all.

    Thanks...Millard
     
  8. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    Are you getting hum or hiss or both?
     
  9. Droog

    Droog

    Aug 14, 2003
    PDX
    Check these out Humfrees They work pretty slick, better than just plastic washers.

    Pretty sure all your gear has balanced I/O. Though I use balanced whenever I can, swapping out all your cables may not do you any good, if its not your cables causing you grief to begin with. I do recomend using balanced audio when you can.

    You might look for any ground lift switches. Though I don't think any of your gear has them.

    I had some nasty, well not nasty, but annoying buzz in my chain last week and it was coming from my bass, that sucks, rolled back the treble and the buzz decreased, but well so did my treble :mad:

    Good luck.
     
  10. millard

    millard

    Jul 27, 2004
    SoCal
    Can't seem to find the HumFrees locally, though it certainly seems that if you used nylon washers on both sides of the equipment and poked a couple between the boxes as spacers you would get the same effect. Might be a little easier to install as well.

    That said, I'm a sucker for the "right" solution, so I may be ordering some humfrees before long.

    Millard
     
  11. Droog

    Droog

    Aug 14, 2003
    PDX
    Yeah I have had a hell of a time getting them locally, you pretty much have to get them from AMS or that sight that I linked. Yeah I think you could make your own, I even thought that pieces of leather would work pretty good, might me spendy if you don't have scraps, but it would look cool.
     
  12. wyliee

    wyliee

    Jul 6, 2003
    South Hill, WA
    I've used Humfrees for a long time and have never had problems with noise. Granted, I don't know if I can directly attribute that all to the Humfrees. Still, it certainly doesn't hurt to do.