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Topic: Grounding the Bridge? On my homebuilt project |
Bill Brunt
From:
Texas, USA
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Posted 7 Aug 2012 10:40 am |
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I read in a post that the bridge of the guitar should be grounded.
When I don't ground it, there is a slight hum (not offensive), but when I do, if the bar or my hand is not in contact with the strings, the fingerpicks cause what I guess is a little short, audible upon contact.
What is your advice? Don't ground?
Here is what I am working on.
I had asked advice in an earlier thread regarding the replacement of the pickup on a cheap asian lap steel. One of our forum members (Len) graciously offered a pickup, and I gleefully accepted. It is a 12 string ToneAligner. Obviously, it would be a waste to place it on the little guitar, so I am building this one:
I am halfway done, but couldn't resist the temptation to slap it together temporarily, just to hear it sing.
It is sweet sounding!
I have to take it back apart to sand, stain, trim the length and neck width down a bit, paint the bridge and nut, etc, etc.
It is made with two layers of 1x6 Red Oak, using a jig saw, screwdriver, a hand drill, and file.
As tough as the Red Oak is(ate up jig saw blades), it is very light, and I may add another layer just to make sure it is not affected by flex.
The fretboard is a piece of hardwood flooring  I had laying around in the garage. I bought a router at Harbor Freight just take the thickness down to about 3/32 - 1/8 inch.
I used a file to cut the 'frets'.
Please don't ask what the white dots are - they are just temporary 
Very utilitarian, but oh, so sweet. |
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Steve Ahola
From:
Concord, California
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Posted 7 Aug 2012 7:01 pm
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If you shield the control cavity when using a humbucking pickup there shouldn't be much of a difference when you lift your palm up from strings that are grounded. But I usually leave my palm on the bridge for muting, etc.
One suggestion: StewMac sells ferrules for the top of the guitar to keep the strings from digging into the wood. (It is easy to find the ferrules that go on the bottom of the guitar since they have been used on telecasters for 60 years now.)
Good luck with your project!
Steve Ahola
_________________
www.blueguitar.org
Recordings on electric guitar:
http://www.box.net/blue-diamonds
http://www.box.net/the-culprits |
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Bill Brunt
From:
Texas, USA
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Posted 7 Aug 2012 7:20 pm
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Thanks for the advice, Steve.
I didn't know about shielding the pickup cavity.
I think I will try the ferrules. The strings actually lean against the bottom leg of the angle, but the ferrule idea would make it look more finished. |
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Denny Turner
From:
Oahu, Hawaii USA
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Posted 8 Aug 2012 1:30 am
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Bill,
There are a lot of factors to know to fully answer your question(s) and choices for metal-to-metal "kissing" on the strings, as well as other noises that can get into a guitar circuit.
If you have volume and tone pots hooked up somewhere, ...then if you post a good clear picture of your volume / tone / cap / switch wired up ...so that we can see where every wire goes; Then Fo'Bros that know can better advise about a number of factors in there.
The sound of the picks on the strings could be acoustic upon contact, or it could be electronic capacitance "sparking" just before the first pick makes contact with the strings, ...or a combination of both. IF your circuit is working better grounded to the strings (and it should, all things considered) then the circuit could be sensing that contact better and thus more noticeable. But it's very difficult to assess your circuitry without seeing it.
If you have volume and tone pots hooked up, it will also help us to know what the pot and cap values are, ...and the static impedence (ohms) value of the pickup which can be read between the pickup leads if one of the leads are disconnected from the circuit. Matching pots and cap values to impedence is important. If you have no volume and tone pots then there is no high freq filter, which could accentuate hearing the high frequency "sparking" of the picks or bar kissing the strings, unless a "VHF" filter cap (resistor optional) is hard wired in.
Is the pickup split-coil? And are the 2 coils wired in series or in parallel? If you are going to split the coils for selective single coil use, then you will likely want a strings ground.
12 strings and their span, and the size of coil and strength of magnets, and probably a hefty static impedence, would likely be a pretty good antennae for outside electronic noise, although your description sounds like the pickup is doing a good job of humbucking unless where you're playing it is extremely clean of free-air electric noise. MEANING I would guess that a strings ground would be wise, along with other nuances of the guitar's circuitry done right as well.
But knowing what all is involved in your circutry is neccessary to really know what's going on and answer your question(s).
But there's also the option of hit-and-miss ... trial and error ...and going with what suits your assessments best. Some folks do quite well with that approach ....but usually not.
Discussing your electronics and circuitry will go a long way of getting it right.
Very Best Wishes,
_________________
Aloha,
Denny T~
http://www.dennysguitars.com/
Please help support humanity:
http://www.redcross.org/en/aboutus |
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Bill Brunt
From:
Texas, USA
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Posted 8 Aug 2012 5:22 am
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Thanks Denny.
At this time there are no pots. When it is finished, they will be to the right of the bridge, in the open area.
...that is, unless I chicken out, and don't install volume and tone pots.
Right now, I have the black and bare wires on the pickup going to ground, and the third(red), I guess you would say hot.
The only thing I know about electricity is up usually turns the lights on, and down is off - but not always:)
The sound is definitely electronic, so it may be the sparking, you mentioned, and needs the high freq filtering.
As for tone, I like it as it is, but what do I know?
Here is what it sounds like, don't listen to the playing, I obviously didn't as I was doing it:) I was scared to death recording, and in the privacy of my own home!
http://www.norbil.com/Music/Faded%20Love%20Homemade%20Steel.mp3
Do you have suggestions as to pot and cap values to start with? |
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Denny Turner
From:
Oahu, Hawaii USA
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Posted 13 Aug 2012 3:44 pm
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Bill,
| Quote: |
The sound is definitely electronic, so it may be the sparking, you mentioned, and needs the high freq filtering.
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Very high freq filtering might be helpful, but not neccessarily the main problem. You see, the higher the impedence of a pickup (assuming all thingies in the pickup are reasonably balanced) .....and a 12 string steel pickup is probably very high impedence..... the hungrier that pickup is for ground when operating, ....and there is quite a resistance between that pickup and the guitar, amp and house or electric companies route to earth ground; BUT not much resistance to the gound supply of electrons in the atoms of your body which begins at those finger picks; So if there is no other strings-ground wire to be communicating with your body electrons, then the picks providing that route can be quite noisy as the + swing of the guitar's electricity jumps the gap ("sparks") between the picks and the strings just before the picks make contact with the strings, AND before the picks make good contact the strings "sizzle" vibrating onto and off of the picks. BUT, with the strings grounded then the fingers following the tone bar should lead picking unless the tone bar is lifted; And lifting the tone bar and placing it onto the strings should always be led by by the dragging fingers making contact first, except for hammer-ons where a finger of the picking hand can maintain contact with the strings for that extra human-body ground source.
The founder of Danelctro, Nathan "Nat" Daniels, came up with an ingenious way to afford his late 1960's Dane model guitars a route to the player's body ground: He drilled a small hole between the pickup cavity and the back of the guitar, ....ran a ground wire through that hole, ....inserted a stainless steel phillips head screw with a head about 1/4" diameter, .....the screw threads dug into the wood and wire and the head of the screw communicated with the player's body ground by being in contact with the player's abdomen clothing. Prior to the Dane series whose pickups were mounted to the pick guard, Dandlectros pickups were mounted through the back of the guitar and their mounting screws provided that human-body contact supplemental human-body ground. I've thought that providing a ground contact on the back of a guitar would be a great for a lap steel ....although better for there to be a sturdy metal strip running along the center of the back of the steel to make contact with both legs of the player, and thus good positive contact and no need to have your hands on the strings to provide body ground.
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| Do you have suggestions as to pot and cap values to start with? |
A tech would have to know the impedence of both coils separately (or collectively if not wired for split coil switching); And if split coil single coil and dual coil were planned, and / or series / parallel switching planned, then different cap & resistor values for each of those switched circuits would "need" to be planned in to provide the best values for 1 or 2 coils and series or parallel coil switched circuits scheme.
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Stewart McDonalds has a lot of free online information about different wiring schemes and componant values for different circuits and different sound preferences; Click on 'Electronics'.
http://www.stewmac.com/freeinfo.html
My website also has some pages of some guitar schematics and circuit logics and links to other guitar circuit design info (see menu bar on the right side of this page):
http://www.dennysguitars.com/tech1.html
Hope this helps in the near and longer term,
Best Wishes,
_________________
Aloha,
Denny T~
http://www.dennysguitars.com/
Please help support humanity:
http://www.redcross.org/en/aboutus |
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