johnrcurry
Rookie Solder Flinger
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Post by johnrcurry on Mar 21, 2006 14:22:43 GMT -5
I am undertaking to shield my very noisy two-pickup electric bass. I’ve read through the “Quieting the Beast” instructions a number of times, but still have some questions. I’d welcome some advice from you folks. Here is what I’m dealing with. . .
The bass has one P-bass type pickup and one J-bass type pickup. The pickups are mounted directly in the cavities on the front side of the bass. There is no pickguard. There are two volume controls and one tone control. They are mounted in a cavity on the back of the body. There is a plastic cavity cover on the back. The control knobs are metal. The control knobs seem to be connected to the bass’s ground in that they noise quiets when I touch the knobs. The output jack is on the bottom edge of the body rather than the front. There are short “tunnels” from each of the pickup cavities and the output jack plate leading into the control cavity. There is a ground wire from the bridge into the control cavity. The wires from the pickups are not shielded.
My plan is to: 1) shield the control cavity, the pickup cavities and the inside of the control cavity cover; 2) connect the shield in each pickup cavity to the shield in the control cavity with a wire; 3) connect the bridge ground wire to the shield in the control cavity; 3) “star-ground” the pickups and the controls; 4) connect the shield to the star ground terminal via a ring terminal on one of the control pots and a .33uf 400v capacitor; and 5) replace the two wires from the output jack with a shielded cable grounded to the signal return/star ground.
Here are my questions. . .
In light of the open-top pickup cavities (i.e. no “top” created by a shielded pickguard) will shielding these cavities do much good?
My control situation is reversed from the strat drawings and diagrams in that I have two volume and one tone pot, rather than two tone pots and one volume pot. Other than wiring my two volumes similar to the one volume in the diagrams and my one tone similar to the two tones in the diagram, is there anything tricky about it that may goof me up?
Will my metal control knobs, which seem to be connected to the bass’s ground, cause any problems?
Am I missing anything, or are there any other traps for the unwary that you can warn me about?
Thanks in advance for your advice
John
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Post by UnklMickey on Mar 21, 2006 15:54:06 GMT -5
John,
Welcome to "GuitarNutz"
i am probably not the best person to ask about "Quieting the Beast", so guys, help add to this!
the usual method also includes metal foil on the back-side of the pickguard.
the pickguard, pot cases, string ground, pretty much anything that can be touched (except the output jack) is connected to the shielding system.
that leaves you a few options for your star-ground.
perhaps an insulated turret lug, or the low terminal of one of your volume controls.
it wasn't clear from your statement in part 4 of your plan, if you are going to use the ring terminal on one of the control pots as the star-ground....don't.
since you are going the "d.c. protection" route, your metal control knobs would then be at star-ground, rather than separated by the cap like the rest of your shielding.
do yourself a favor, and make a map of the control and pickup wiring before disconnecting anything.
my guess is the 2 P-bass pickups are connected in parallel to one volume, but it's important to keep track of the polarity to keep them hum-cancelling.
also the volumes may be normal (turning either one all the way down prevents the other from working) or reversed (independent, but "bassy" when both are set to lower volume).
if you create a drawing of how the wiring is connected now, we can give you advice on the possible changes, and how they will affect both the sound and the control functions.
unk
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