Conference napalm::guitar

    Check the grounding of the Guitar/amp system. There should be a
    ground wire attached to the tailpiece of the Guitar so that the
    instrument is properly grounded. Yoy might check thie with an ohm
    meter between a string and your patch cable shield. If the power
    cord on your amp has a ground lug it should go through to there.
    
    Jim
    

    I would say it's definately related to grounding/shielding.  I'd check
    the internal grounding of the guitar first, my strat used to have this
    problem when I changed pickups.  I ran a nice big ground strap across
    the bodies of the volume & tone pots & up to the tailpiece and it
    reduced the hum about 80%. Have you tried another guitar with the amp,
    or this guitar in another amp?  You might check the cord you're using
    too. 
    
    Another thought:  A lot of amps have a switch which is used to select
    the ac power in pattern (for want of a better term).  The older amps
    would sometimes hum when you put the plug in wrong and you could
    eliminate it by reversing the plug.  The switch does the equivalent.
    Does you amp have this?  I've heard of houses, especially older
    ones, that aren't wired standard.  AC power only flows through one
    of the 2 (or 3) wires, the other is a ground.
    
    Not a real technical discussion, I'm a SOFTWARE type...
    
    Greg
        

    
    Re: .0
    
    The problem you are having is common to a lot of older guitars.
    
    Until people starting playing at high volumes in the late sixties,
    few people noticed how poorly shielded most electrics are.
    
    Either shield it yourself or have a repairman do it.
    
    Don't feel bad, I had to have a $1400 bass worked on for the same
    problem.
    
    

Re: 488.1  Ground wire to the Tailpiece/Bridge.
    
       I read somewhere that you definitely DO NOT want a ground running
    from your electronics to the tailpiece.This makes the PLAYER and
    essential part of the grounding system.If the polarity of your guitar
    is different than the polarity of,say,a microphone you touch with
    your lip,the result can be quite painful,perhaps even deadly :-(.
    
       My Bullet Bass had the wire and I removed it.Its noisier for
    sure,but a whole
                    lot safer.
    
    
    		/tomg

    re .4  You can't be electrocuted by passive components (guit, mic)
    unless your wiring is REALLY screwed up... and your body makes an
    excellent ground (although crackle ensues if you let go of the strings)
    
    re .2  AC wouldn't be AC if you were only getting juice through
    1 conductor... I think what you mean is that some older houses aren't
    grounded, and this does tend to be a problem.  hence, solution1,
    above.
    
    Jon
    

	
    RE: .5 
    
    Yes, technically, AC current does not "flow" from one connector,
    but only one side of a two pronged plug has a signal.  The other
    side is a ground.  If you want to prove this, take a light and a
    plug with a wire attached to only one conductor of the socket and
    run the other wire to a known ground.  With the conductor attached
    to one side of the plug, the light will work, attached to the other
    side, it won't. 
    
    What you get with the AC plug turned the wrong way is (I believe...) phase
    reversal, which isn't a problem for most devices which utilize AC
    power, like electric motors.  Others are more sensative, that's
    why you get plugs that have one side bigger than the other on some
    appliances, such that you can only physically put it in the socket
    one way.  If the house is wired correctly, then this is right. 
    I've heard that some older buildings are not wired to the standard,
    simply because of the argument that AC is a push-pull arrangement
    and it doesn't matter which side is the ground.
    
    I have a real old little tube amp which has a plug which can be
    inserted either way, and I *KNOW* that it hums a lot more when it's
    in one way than the other.  I've also seen several amps which have
    a reversing switch...
    
    Greg

    I'll try it, but your story doesn't ring true...
    Why then do 3-pronged plugs (2-phase) exist?
    Why the term "Alternating Current"?
    Why does reversing phase to an electric motor
    often result in reversal of direction of rotation?
    
    I always assumed that 2-pronged plugs simply
    drove devices which did not require a ground...
    But then again, I'm no electronics buff.
    
    Jon

    Jon,
    
    I've done the experiment (way back).  I'm not an engineer type,
    and haven't really studied it enough to be able to explain why.
    Good point about the third prong on the plug.  I don't know why
    it's there.
        
    I also confirmed this with one of the local techno-wizards before
    leaving .6, I wish I had the electrical background to be able to
    explain it better.
    
    Regardless of how it actually works, reversing the plug can often
    reduce hum from an amplifier.  Especially if it doesn't have a three
    pronger.  I can't remember what brand amps I saw with the wire reversal
    switch.
           
    Greg

    
    The switch you'all are referring to is called a "polarity switch."
    This little number can be quite usefull in reducing hum. My amp,
    unfortunately, does not have one. My amp also uses a 3-prong plug,
    which makes reversing it a bit of a problem. 
    
    Oh well, I'll check into shielding the pots and rocker switches
    in the guitar and see what that does.
                  
    much thanks
    
    Rob
    

    My Dean Markley has such a switch, my friend's Marshall does not.
    However, I often buy second-hand equipment, and a lot of the
    plugs have had that third prong ripped right out, and they still
    seem to work fine.  (This means you can turn it around-no hassle).
    Could someone please explain any problems this may lead to -
    I'm sure there must be some...
    
    Jon
    
    P.S.  The polarity switch is often unlabeled, a 3-position power
    switch (for those of you (if there are any) who aren't sure whether
    you have the switch...)

    Yes,you are partially right there is only one "HOT" wire in the
    AC outlet. The polarity reversing switch was put into play because
    some of the amps did not have three prong plugs and the wiring of
    the outlets was/may not be standardized. Therefore, it was not certain
    which way the plug would go into the wall or which stde of the outlet
    was "HOT" and which was "NEUTRAL" (not GROUND although neutral will
    eventually tie to ground somewhere). The switch allowed you to
    compensate for these unknowns at the amp thereby eliminating the
    need for an electrician to verify the circuit.
    
    Yes Virginia... You should have continuity between the guitar tailpiece
    and the chasis ground of your amp. Also you should have the same
    thing from your mike case to ground (***NOT NEUTRAL... CHASIS
    GROUND!!!)
    
    All of your Amps and PAs Should also share a common ground.
                                              SAFE
    
    Jim
    
    
    A properly grounded sysdtem is completelySAFE.
    

    	Hmm. I still think that having my strings grounded to my amp
    
    is asking for trouble.How can I GUARANTEE that all the grounds are
    
    at the same level? You can (almost) never assure that all the gear
    will be plugged into the same circuit.I do agree that properly 
    grounded systems are safe.But can properly grounded systems be
    GUARANTEED.
    
    	I have no desire to start a flame war,I think that I am 
    probably ignorant of some basic electrical fact and would like
    to have the GUITAR/AMP grounding issue explained to me further!.
    
    
    BTW, My Fender Bassman has the polarity switcher.
    
    
    		/tomg

    
    Re: grounding of strings
    
    Most electric guitar pickups are high impedance and need to be properly
    grounded in order to work without humming like crazy.
    
    Some companies have introduced preamps in the past, some stomp box
    types, others onboard, that optically isolate the pickups from your
    amp.  Such an isolation circuit means that there is no longer a
    direct connection between the AC ground and your strings.
    
    One such brand was Carrotron or something like that, and was expensive,
    well over $100.
    
    Another perfect alternative is going wireless 8^)  8^)  8^)
    
    Or you could go to Radio Shack and buy one of those little voltage
    testers for $1.  Touch one lead to your strings, one to your mike
    (a metal part of your mike, like the XLR connector);if it lights
    up, switch polarity somewhere, at your amp, at the PA (but not both)
    until the tester doesn't light up anymore.  Cheap insurance, the
    way I look at it.  
    

    Also, there was a project described in Guitar Player once that was
    a little device to check for proper grounding.  If there's interest,
    I'll dig through the old issues and find it.
    
    BTW:  My Hiwatt doesn't have a polarity switch, and the power cord
    I got with it (you could use a std 3 prong extension cord, the way
    it's designed) has the ground prong ripped out...none too elegantly.
    
    Greg

    
    Greg,
    
    I'd be quite interested in that article in GP magazine. Could you
    send a copy of if to me? I'd appreciate it. 
    
    Send it to:   Robert Woodburn
                  PK03-2/H31
    
    Thanks,
    
    Rob

    Sure.  I'll look it up and post the issue here.  If anyone else
    want's a copy of the article, just send me mail.
    
    Greg

    
     The only reason I disconnected my gnd wire to my tailpiece, was
    to lower the risk of getting shocked between touching my strings
    and putting my face on the microphone, HOWEVER, I now increased
    the hummmm level on my strat. Strats are great guitars, but they
    sure are noisy! When I play out, I take a meter with me and
    measure the voltage between my (grounded) tailpiece and the
    microphone. One time it was so bad that the voltage was 85volts
    between my guitar and the mic. I started checking after I got zapped
    real good one night. I was singing back-up for this group and playing
    guitar and went up to the mic to squeek out my voice and got zapped,
    not to mention the I saw a "blue arc" off the left side of my face.
    It was so noticeable that the band stopped playing cause the other
    guys saw it. Great light show! I didn't get burnt either... lucky
    I quess! Since then I take around my trusty Beckman meter and check
    all the instruments against the mics. Common grounds are VERY
    important!!! I've seen some houses that are wired backwards. Feed
    lines on the neutral side of the switch instead of the other way
    around. Radio Shack has a neet little device that you plug into
    any electrical outlet (115vac/15amp) in your house and little
    lights turn on for certain conditions. Conditions like, the ground
    that's missing, or a hot wire on the neutral pin of your outlet.
    For $10. it's nice to have, if you don't want to get involved with
    an expensive multi-meter. I checked an old Fender amp one time for
    a loud noise problem, but I plugged it into an outlet at my house
    and it worked great and no humm! Something in "his" house was causing
    the problem. He liked to play in front of the TV (which was on)
    and that caused a type of hum not to mention that his house was
    wired improperly. It was a very old house and was built by the owner. 
                      This guy made his own problems!
    Getting back to the subject at hand.... is this guitar noisy with
    other amps? If not... check the noisy amp for bad caps. Isolate
    the problem BEFORE spending alot of time barking up the wrong tree.
     Transistor type amps are usually noisier that tubes, at least that
    has been my experience anyway. As far as the HiWatt having the gnd
    pin pulled out..... some person was playing a gig and didn't have
    a three prong adaptor. What do you do???? Rip out the pin. Not a
    good idea, but in an emergency you have to do what's necessary to
    "adapt" to the situation. (Boy....that joke was bad!). One hint
    for you.... check the obvious and look for something stupid that
    one may have overlooked. Still can't find anything wrong and still
    have noise? Borrow someone elses guitar and plug it into your amp,
    or check your guitar into another amp. Again... isolate the problem
    first, then... RIP THE BUGGER APART AND SHOW NO MERCY, or pay someone
    else to do it!
    
    Good luck,
    Fred
    

    re:10
       Jon,
           By lifting the ground, (cutting off the 3rd "ground" pin)
    you are leaving your self open for problems. Yes, it is true that
    old tube amps didn't have a three prong plug and every thing worked
    fine, but if you take a VAC reading between a microphone plugged
    into a powered PA system and your guitar, or chassis of your powered
    up guitar amp, you will see more voltage on your ungrounded amp
    as compared to an amp that has a common gnd pin that works. True,
    you could turn the plug around to reduce the hum and thus reduce
    the voltage potential between grounds, but it won't be as low than
    if you had a workable ground pin. Some amps can't be grounded the
    way amps are today, due to their circuitry and older technology,
    but if your amp had a ground pin that someone ripped off, then I
    would make it a point to replace that plug. It can't hurt you, but
    not having it might. I'm NOT saying that all owners of old Fender
    amps replace their plugs with grounded 3 prong plugs, because they
    "weren't designed" for it. If you don't still don't believe me then
    get a multi-meter and on your next gig, or band practice check your guitar,
    or amp against the mics and then flip your grounds the other way
    and take another meter reading. You might be surprised at the results!
    I agree with that one idea already stated..... go wireless!
          
    Fred
    

Foam condoms for microphones are only a buck or two.  Buy a few, take
them to gigs, and no shocks no more.  Besides, you can't be sure
who used the house microphone's before you.  :-)

Now avaliable in designer colors.

Dave

    
    Thanks for all the colorful replies folks. I did isolate the problem.
    It's my guitar. It's a new ES 355 that has no shielding whatsoever
    and no ground to the tailpiece. So the sucker is noisy. So I took the 
    guitar to a guitar repair specialist who's gonna fix it. He's also 
    gonna smooth out my fret board and shim up my nut (my G-string buzzes 
    open). 
    
    Thanks again,
    
    Rob 

    
    Sorry to take so long with the G.P. article.  I finally found it.
    It's in the Dec. 86 issue, the one with Billy Sheehan[sic] on the
    cover.
    
    There's not much to it, basically a wire that attaches to the mike
    stand and a little plastic box with a copper plate on the back to
    press on your guitar/bass strings.  There's a little light in it
    to warn you if there's voltage.
    
    Sounds just like the little test lights you buy to check the timing
    in a (air cooled) VW.  You can get one of those at any auto parts
    place for about a buck.  Even has allegator clips on each
    end...Probably a little sparse on the length though (about 12").
    
    BTW:  Robert, if you still want me to copy the article for you,
          I'll be glad to, it's pretty trivial though.  Send me mail
          if you still want it.
    
    Greg