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 Post subject: Star ground a Rick?
 Post Posted: Fri Dec 16, 2005 5:53 am 
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Is it possible to shield/star ground a Rick 4003 or will the non-interactive pickups make that an impossibility?


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 Post subject: Re: Star ground a Rick?
 Post Posted: Fri Dec 16, 2005 9:28 am 
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You can wire the grounds in a star if you like but there's no particular advantage other than the fact that it's a bit easier to keep things straight.

The only rule you simply don't want to break ever, whether you wire daisy chain or star, is never ground any component in more than one place. That's usually what happens when foil or conductive paint is applied in the circuit cavity. The star configuration simply keeps you more organized in this regard.


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 Post subject: Re: Star ground a Rick?
 Post Posted: Fri Dec 16, 2005 10:01 am 
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Thank you... I meant to post this in basses only BTW.



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 Post subject: Re: Star ground a Rick?
 Post Posted: Sat Dec 17, 2005 12:02 am 
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Okay, it's moved here and all the various versions of this thread removed. Let's therefore put all further comments here.


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 Post subject: Re: Star ground a Rick?
 Post Posted: Mon Dec 19, 2005 4:15 am 
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Quote:
The only rule you simply don't want to break ever, whether you wire daisy chain or star, is never ground any component in more than one place. That's usually what happens when foil or conductive paint is applied in the circuit cavity.
John, you seem against foil or conductive paint shielding. Could you explain why and what that and/or grounding in more than one place causes? This is interesting. Has it to do with using hi-gain single coil pickups?


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 Post subject: Re: Star ground a Rick?
 Post Posted: Mon Dec 19, 2005 5:56 am 
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Not at all, it's just that 99% of the shield jobs I've seen have been done poorly and have the potential for increasing noise rather than reducing it.

The problem is ground loops, specifically areas of shielding or wiring that don't have a perfect connection to ground due to resistance in the path. These areas can act as antennas and/or induce loops of flowing current that nullify the intended goal of taking all extraneous signals directly to ground.

If you use foil or paint, just as in wiring, you must have only one point going to ground. For instance, if you put foil underneath the pot mounting posts through the pickguard, either cut circles so the pots don't touch ground there or remove all other ground connections from the pot shell. Make only one connection between the shielded body cavity and any other ground point.

This is the simplest rule- only one path to ground for any point in the system. That being said, shielding is almost a black art and you simply have to test and be willing to make changes based on the results.


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 Post subject: Re: Star ground a Rick?
 Post Posted: Mon Dec 19, 2005 8:20 am 
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Ok, that makes sense and good advice. With my electronics education/experience, ham background, and what I knew about shielding, I was curious to hear your take after that origional comment. Not necessarily a black art, but there are definate dos and don'ts, which you pointed out, and in fact you can easily make it worse. The ideal shield would be like a metal can, but then the pickups wouldn't work, so you compromise and let them stick through. And a really good ground (zero ohm/impedance) to that "metal can" is imperative or as you stated you make it worse. Not a casual fix, but not impossible.

Thanks for the additional info.


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 Post subject: Re: Star ground a Rick?
 Post Posted: Mon Dec 19, 2005 9:11 am 
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Okay, good, it helps to know that you understand this kind of thing. The ideal situation for a can-like cavity shield would be one with finger contacts, as you might see inside of a duplexer or quality tranceiver front-end. Unlike working with RF, you really can't use caps in the circuit to bleed off electrostatic noise your circuit might be exposed to or use feed through caps without affecting the sound.

All you can do is use best practice principles and hope for the best.

I'm WD6GDL, by the way.


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 Post subject: Re: Star ground a Rick?
 Post Posted: Mon Dec 19, 2005 9:21 am 
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KA8QML, but haven't been active since chasing the kids around the many sports they partook in. Got two free college degrees out of it though!


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 Post subject: Re: Star ground a Rick?
 Post Posted: Mon Dec 19, 2005 10:42 pm 
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Yes I'll second that... that it has taken alot of fiddling and forethought to get the star grounding situation correct.. I find that it has reduced noise substantially. from my single coils. Theoretically, another plus for star grounding is the ability to keep your hardware and strings grounded behind a .33 400 volt capacitor. I play through a 54 year old amp when recording... should it fail, the .33 cap should "absorb" the lethal voltage punch. I have one guitar now wired this way, although it and I have not been subjected to a true test of this theory. But I have been shocked before (through the strings) at an outdoor gig (with modern equipment and it was a sunny day). It was quite unpleasant, so decided to try this when I heard about it.


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