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Conference napalm::guitar

Title:GUITARnotes - Where Every Note has Emotion
Notice:Discussion of the finer stringed instruments
Moderator:KDX200::COOPER
Created:Thu Aug 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3280
Total number of notes:61432

1787.0. "Earth Hum ?" by BAHTAT::BELL (SWAS Leeds 845 2214) Fri Apr 20 1990 11:42

    I have a Japanese Fender Strat which hums a lot. What I mean is that
    unless I am actually touching a metal part of the guitar I get a loud
    hum from the amp. Our bass player has suggested disconecting the earth
    wire which goes from the pick ups to the back plate. I am not an
    electrical engineer and I don't want to leave myself susceptible to
    electrocution so would anyone care to comment on the wisdom or
    otherwise of this move. If not has anyone got any other suggestions.
    
    Thanks
    Richard Bell  
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1787.1single coils humMILKWY::JACQUESFri Apr 20 1990 12:5617
    Most Fender instruments with single coil pickups hum, because pickups
    in general act as an antenna, and unless they are humbucking pickups,
    the hum will get to your amp and get amplified along with your sound.
    BTW, the hum is there when you are playing, but the music drowns it
    out. Some folks get around this by using a noise gate, but these
    devices tend to chatter as the notes fade, because when you are right
    at the threshold the gate can't decide whether to be open or closed.
    
    A better way to eliminate hum is to replace the original pickups
    with humbuckers (preferably a stacked humbucker, because these
    require no body routing). 
    
    By the way, if you are using a compressor, be aware that they tend
    to increase noise levels.
    
    Mark
     
1787.2BuzzzzzzzzzzAQUA::ROSTBad imitation of Jerry JemmottFri Apr 20 1990 13:107
    
    Disconnecting the ground (earth) wire will only make the hum worse. 
    Strats hum, it's the nature of the beast.  There's lots of things you
    can do to minimize it through careful shielding.  Do a dit/tit=shield
    to find some notes in here on how to do that.
    
    								Brian
1787.3SALEM::ABATELLII don't need no stinkin' BoogieFri Apr 20 1990 14:0124
                      -< Don't waste time...  shield it! >-

      There's one noter that works in Salem (Hi Don) that has a Squire
    Strat that complained about noise/hum/hiss... etc, has reduced
    the noise greatly. Alot of the pre-cbs Fenders (p-bass in particular)
    had a thin metal plate used for shielding the guitar that was cut to
    match the pickguard and was found between the back of the pickguard
    and the body. Don added and grounded some copper foil to his Squire and
    also added some shielding tape (a metal foil with a sticky back)
    and formed it into the cavity of the body. I have a '69 Strat that
    is ALOT quieter than alot I've played and when Don and I compared
    the two Strats there wasn't much difference in noise. So to conclude...
    IT WORKS! New pickups would help, no question, BUT if you like the
    tone of your pickups, but want to get rid of 80% of the noise...
    shield it! 
      If you play with a transistor type amp, you *will* have more background
    noise. Just the nature of a transistor beast actually, but shielding
    will still help ALOT! Conductive paint is also good, but messy.
      Check out all the options and go with the one you think is best
    for your application.
                                       
    Rock on,
    	  Fred (long time Fender user... and loving every minute of it!)
1787.4Definatley pickups and/or shieldingVAXWRK::SAKELARISFri Apr 20 1990 15:0316
    Yeah, I second the shielding motion. I just replaced the pickup with
    the stacked humbuckers that Mark Jacques mentioned, though I didn't do
    it because of a noise problem. But I must say that after having the
    pickguard off the guitar and seeing what's underneath, shielding is at
    a minimum on at least the Jap Strats ( mine 's Jap too). Don't know
    about the others.
    
    Seems to me that all guitars have some hum when your not touching the
    strings. The magnitude is a variable depending upon, as mentioned, the
    pickup type (single coil = greater hum) and the amp itself including
    it's settings. If you don't want to change pickups, and the hum when
    your not touching the strings or the hardware continues to bother you,
    play the guitar more or turn the volume control down. Don't remove any
    grounding or shielding; you need more not less.
    
    Sakman
1787.5life is a compromise I guess.PELKEY::PELKEYI love being a turtle!Fri Apr 20 1990 17:017
yea, strats,, the down side is the noise.

I call it the single coil blues...


But, for what it's worth, I'll take the noise to have the strat.

1787.6LARVAE::BRIGGSThey use computers don't they?Sat Apr 21 1990 08:5624
    
    Hi Richard...
    
    I too have a Jap Strat (about 10 months old) and this also has hum just
    as you describe so I guess its normal. 
    
    One thing I have noticed  though, I have a two way mains adapter at
    home and If I plug my amp in using this adapter then the hum I get is
    worse and I'm talking about the hum emanating from the guitar not
    amplifier hum (if you see what I mean!). Also, I visited a friends
    house (old house, old wiring) and this effect was even worse.
    
    It would seem this 'strat hum' is affected by the quality of mains
    earthing etc. Havn't thought too much about it, maybe it makes sense.
    In short, in my nice new house without using adapters etc the hum is
    noticeable but only really if you listen for it.
    
    Re .-2, surely a valve amp characteristically noisier than a transistor
    amp? My Fender Champ has that typical mains hum you used to get from
    old TVs and radios (nothing to do with the hum referred to in this
    note).
    
    Richard
    Basingstoke
1787.7O-Tay... try everythingSALEM::ABATELLII don't need no stinkin' BoogieMon Apr 23 1990 15:1841
                     -< O-Tay...  check EVERYTHING then! >-


       Single coils sound great (IMHO), but next to humbuckers they
    are noisier. Fact...  no? You need to take EVERYTHING into 
    consideration. It's true that this noise will/may vary from
    place to place, pub to pub due to alot of things. Wiring of the
    house, age of the amp (being able to cancel external noise) the
    type/amount of effects chained between the guitar and the amp, the 
    type of signal cable/cables being used, shielding, or lack of on your
    guitar, whether or not the house has "dimmer" switches that are
    being used, and lastly...  anything else that comes in contact
    electrically. Over here in the States, I've compared (too many times)
    valve amps vs transistor amps and on the whole (at the same volume)
    the valve amps tend to be quieter. When they are played "clean" they are
    about the same *but* you switch to the dirty/saturated channel and
    that's where the big difference is. NOISE! Amp noise however has
    nothing to do with your guitar noise...  just one more form of "hash"
    that isn't needed in the background. If you still don't believe me
    compare a...  oh...  I don't know.... OK! Compare a Peavey Special
    130, and then compare it to a Peavey Triumph 100 and then you tell me
    which has more "background noise". Both put out "similar" power
    too, or maybe a Marshall "mosfet" 100 watt vs a Marshall (valve) 
    Lead 100!
    	
	Back to the subject at hand, I'd check the guitar noise out by
    process of elimination:
    	1.) Go direct from guitar to amp
    	2.) Does the noise increase when using a "lead" channel, or
            doesn't it matter.
    	3.) Change cables, even borrow a cable from someone else to
            see if your cable isn't rejecting RF from somewhere else.
        4.) Never use a 3 to 2 pin adapter unless you have to.
    	5.) Does a guitar with "humbucking pickups" have the same effect?
    	
    Take the time to track down the problem. Chances are it'll go back to
    guitar shielding, or the lack of it for that matter. I've seen cheap
    guitar cables be the problem too!                   
    
    Good luck!
    		Fred
1787.8RFI Shield..DNEAST::GREVE_STEVEIf all else fails, take a nap...Tue Apr 24 1990 13:1722
    
    
    
    	Yeah, I agree with Fred, single coils are worth the trouble.  I use
    metal foil from my local auto parts store, and put a layer on the back
    of my pickguard.... Make sure to connect the screw holes and make sure
    that there's foil underneath all the pots and switches... so that the
    foil goes to ground.  This foil sheilding (I'm no double E either)
    provides an RFI ground (Radio Frequency Interference) for all that
    nasty 60 cycle crap.   If you elect to do this mod, please be careful,
    that foil stuff is sharp as a razor and needs to be handled carefully..
    I learned the hard way... geee.. Mr Wizard, how come my hands hurt so
    much when I flex them???  ;^)
    
    	Nother tip... when shaping the foil, lay it over the pickguard and
    make a small indentation to outline the pickguard, then use scissors to
    make your cutout....    BTW, I'm getting $25 around here for installing
    this mod for our local music store, and people rave about how quiet
    their guits gits!
    
    
    Steve
1787.9IOENG::JWILLIAMSWelcome to the Bush LeagueWed Apr 25 1990 18:3419
    The main cause of AC noise is close field capacitive coupling. This
    means that the coupling is an equivalent of a capacitor between your
    power lines and your guitar. There are four main ways to improve the
    situation:
    
    1) Add a faraday shield. This has already been discussed for guitars,
    but it is equally if not more important to have a high quality cable.
    
    2) Lower the impedance of the circuit. This means using a low impedance
    input preamp or a low impedance pickup. Pickups with active electronics
    and/or onboard preamps help alot.
    
    3) Raise the signal output. Put in hotter pickups and/or raise the pole
    pieces.
    
    4) Cancel the noise. This is what humbuckers do, among other things.
    
    							John.
    
1787.10OK after all.BAHTAT::BELLSWAS Leeds 845 2214Fri Apr 27 1990 11:225
    Thanks for the various suggestions, though I think nothing needs doing.
    I realised that the bad hum only occurs when rehearsing at our bass
    players house. Seems his earthing ain't too good.
    
    Richard
1787.11feel adventurous???HAMER::KRONLost in a strange landFri Apr 27 1990 13:467
 I don't think disconnecting the ground will help.....you might want
    to try this. Get a spare p/u like the ones you're using and take
    off the magnet, and wire it BACKWARDS between the two lugs on the
    output jack....maybe you can fit it in the trem cavity. I believe
    PRS basses use this trick to eliminate hum on their basses without
    losing the single coil clarity...
    -Bill
1787.12Hum Cancelling trick...DNEAST::GREVE_STEVEIf all else fails, take a nap...Fri Apr 27 1990 19:3310
    
    
    
    	But, in order (brace yourself, dumb question coming up..) to cancel
    the hum wouldn't the two coils have to be in close proximity toi each
    other so that the signals they were receiving were as close to equal
    and opposite as possible???
    
    
    
1787.13naaaaah!!!!!HAMER::KRONLost in a strange landMon Apr 30 1990 19:194
nope....int this case it won't make any diff. cuz the hum
    shouldn't be affected by a wood guitar body......it should work
    jest fine!!!!
    -Bill (t-3) :^p