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Jazz Shielding Pictorial (Big Images Warning)

#161
Hey Vic,

First, I agree with what you've said and am appreciative that you responded to the posts here I missed (had a TB/Mozilla headache that's just now cleared up).

But...

I think it's important for people to realize that while star grounding is the ideal, in a bass circuit with low voltages and low current and such short distances, there is no practical or audible difference between "exact" star grounding and the "psuedo" star grounding I used in the pictorial and in the diagrams.

I used the wiring I did so there wouldn't be a bunch of wires between the control cavity and the control plate. So all of the ground wires from the controls go to the output jack, and all the body ground wires go to the lug in the cavity. On my bass, the cavity shielding is tied to the control plate when the control plate is screwed down, but one could also run an additional wire from the output jack to the cavity ground lug.

My approach has the benefits of star grounding but is more practical as it decreases the number of leads inside the cavity.

While in an amp I would insist on full star grounding, and even in effects circuits, in a bass like this, there is no difference to justify the hassle.

One could solder the pot lugs to the pot cases rather than run separate grounds like I did, but I think this is an area where the "pseudo" star grounding does sound better.

Vic said:
Remove both black wires from the pickups and solder them to a lug in the cavity. Then take a third black wire and solder it between the output jack (where the bridge pickup ground was connected) and the lug. The plate should ground all the pots and jack together, so you could just remove the common ground wires also connected to the output jack, but if you want a perfect star, just disconnect them from the jack and solder them to the lug as well.. If your bass is fully shielded, then the "ground can" will surround everything, and everything in the ground can will be connected to the ground can from a common point, which will give you a perfect star config.
Click to expand...
 
#162
Lyle Caldwell said:
Hey Vic,

First, I agree with what you've said and am appreciative that you responded to the posts here I missed (had a TB/Mozilla headache that's just now cleared up).

But...

I think it's important for people to realize that while star grounding is the ideal, in a bass circuit with low voltages and low current and such short distances, there is no practical or audible difference between "exact" star grounding and the "psuedo" star grounding I used in the pictorial and in the diagrams.
Click to expand...
Very true. I shoulda' pointed this (reality check) out as well, instead of just simply answering the question without that qualification.

However, the shielding part IS very significant... at least it was for me. :)
 
#164
I didn't know how a proper shielding was done before I havent read this topic!!!
Now I have done it and it works and i never will build or play a nother bass with out it!!
the thing is that single coil pickups have a more wide frequecy spectrum than most humbuckers. But we all know how the single coils hum and buzz when there ia inproper shielding/grounding job done on them!!
But when you get it in the right order then it works like a dream come true!!!!
thanx for all the info and input!!!
 
#165
This thread is great. So much great information. I just tried shielding my P/J and had a quick question... Someone said that when this is done it shouldn't matter if you're touching the strings and such. I still have some buzz going when my tone knob is on, and I expect a certain amount of hum from the single coil jazz pickup, but it seems louder than what I'm used to. It also hums more when i touch any of the metal knobs. I disconected the bridge ground, so theres no problem when I touch the strings, but I think this sounds like i did something wrong.

Two quick questions about it... First, on the wiring diagram on the previous page, are the lugs on the pot ordered looking down the shaft ot them (i thought this was standard) or is it a drawing of how it should look from the back of the control plate? I was thinking that I did the wiring backwards and am sending all of the hum to the amp and not the ground.

Also, I know that this is probably key, but I haven't connected the jazz pickup route to the rest of the shielding yet. I thought that this is why there's more hum than I expected but I didn't think that it would explain the extra hum when I touch metal that's connected to the circuit.

If anyone has seen something similar before, I'd appreciate any help that can be given... I know its tough to diagnose these things online, but I really dont trust my local music shop. Thanks for the help guys.
 
#169
Hey, I'm curious about something.

I want to do this to my Jazz copy, because it hums like nothing else! I opened the control panel, with the original intention of replacing the completely oxidated pots, and the scratchy tone pot. It appears there is a stack of ground loops, which I plan to rectify.

Now, all of the wiring (except bridge ground) is coaxial (outer layer ground, inner core signal). Once the bass is sheilded, can I just wire all the common grounds inside as a star, and do all the hooking up of signal wires with unsheilded wire (because the copper/aluminium shielding would sheild the wires anyway)?
 
#170
parkerd said:
Hey, I'm curious about something.

I want to do this to my Jazz copy, because it hums like nothing else! I opened the control panel, with the original intention of replacing the completely oxidated pots, and the scratchy tone pot. It appears there is a stack of ground loops, which I plan to rectify.

Now, all of the wiring (except bridge ground) is coaxial (outer layer ground, inner core signal). Once the bass is sheilded, can I just wire all the common grounds inside as a star, and do all the hooking up of signal wires with unsheilded wire (because the copper/aluminium shielding would sheild the wires anyway)?
Click to expand...



Well, my questionis answered now. :D

I've shielded the bass with alfoil, and it's reduced the hum quite a bit (not completely though).

I've noticed one problem, though, and I was wondering if anyone has experienced it with their jazz bass or copy.

My jazz copy orignally had an annoying problem of intermittent squeaking, which would only go away if I turned the tone knob all the way counterclockwise (right). I would have thought it was a bad pot, but I've replaced all the pots, wiring and the tone cap.

Originally, the tone cap was two 0.047uF in parallel (making it effectively a ~0.1uf cap). I've now replaced it with a 0.047uF cap on its own, as that is what is used in default jazz wiring, so I went with that.

I've ruled out that it may be a pup, as I have tried soloing each pup, and the squeak remained until I either muted both pickups (no output), or turned the tone knob right.

I've changed the cap, so it's not the cap itself, but maybe it's the type of cap? It originally had green caps, and I've replaced it with a green cap. Do you guys use green caps, or ceramic caps, I'm thinking that may be it? Have any of you had a problem with intermittent squeaking on your jazz basses?
 
#171
parkerd said:
Well, my questionis answered now. :D

I've shielded the bass with alfoil, and it's reduced the hum quite a bit (not completely though).

I've noticed one problem, though, and I was wondering if anyone has experienced it with their jazz bass or copy.

My jazz copy orignally had an annoying problem of intermittent squeaking, which would only go away if I turned the tone knob all the way counterclockwise (right). I would have thought it was a bad pot, but I've replaced all the pots, wiring and the tone cap.

Originally, the tone cap was two 0.047uF in parallel (making it effectively a ~0.1uf cap). I've now replaced it with a 0.047uF cap on its own, as that is what is used in default jazz wiring, so I went with that.

I've ruled out that it may be a pup, as I have tried soloing each pup, and the squeak remained until I either muted both pickups (no output), or turned the tone knob right.

I've changed the cap, so it's not the cap itself, but maybe it's the type of cap? It originally had green caps, and I've replaced it with a green cap. Do you guys use green caps, or ceramic caps, I'm thinking that may be it? Have any of you had a problem with intermittent squeaking on your jazz basses?
Click to expand...

could be the pickups themselves, on my older cheapie bass, the P pickup had loose coils and would squeak every once in a while. I think it is called microphonic
 
#172
Hi Lyle, I have been reading up on this more and more recently and have decided to shield my MIM Jazz. I cant seem to find any of those Orange drop caps that have been mentioned but I could find this.


Invalid Link Removed

Would that be just as good to use? I would be ordering it through work so finding a suitable cap from RS would be ideal for me. The copper adhesive tape came yesterday and I am itching to get started.
Thanks in advance and sorry for innadvertantly bumping a really old thread.
 
#173
Any ceramic or film cap will work. I use the Orange Drops because the leads are sturdy.

The_D said:
Hi Lyle, I have been reading up on this more and more recently and have decided to shield my MIM Jazz. I cant seem to find any of those Orange drop caps that have been mentioned but I could find this.


Invalid Link Removed

Would that be just as good to use? I would be ordering it through work so finding a suitable cap from RS would be ideal for me. The copper adhesive tape came yesterday and I am itching to get started.
Thanks in advance and sorry for innadvertantly bumping a really old thread.
Click to expand...
 
#174
Great thread.
Here's my issue:
I've been tinkering around with shielding/grounding a 1998 MIM Jazz Bass. I've tried numerous star-grounding and sort of star grounding schemes, I've tried all available wiring configurations, but I'm still getting hum. Interference. If I hold the bass horizintally, it sounds awesome. Clean and clear. But when I wear it normally. It's humming away and sounds like a light saber as I move around a bit. I've turned all the lights off. I've turned the AC off. It's annoying. What do you think? I've checked the continuity between the copper sections (I've covered everything), I've replaced the pots. I've done a voodoo..well nevermind. Any opinions?

Thanks,
Tim
 
#175
timothyday said:
Great thread.
Here's my issue:
I've been tinkering around with shielding/grounding a 1998 MIM Jazz Bass. I've tried numerous star-grounding and sort of star grounding schemes, I've tried all available wiring configurations, but I'm still getting hum. Interference. If I hold the bass horizintally, it sounds awesome. Clean and clear. But when I wear it normally. It's humming away and sounds like a light saber as I move around a bit. I've turned all the lights off. I've turned the AC off. It's annoying. What do you think? I've checked the continuity between the copper sections (I've covered everything), I've replaced the pots. I've done a voodoo..well nevermind. Any opinions?

Thanks,
Tim
Click to expand...
Some environments are just brutal enough that you might have to go with humbuckers. Sounds like you've checked your shielding and it ain't enough, so that's the only thing left I guess.
 
#176
Hi there
Just a beginners question.
I've installed recently some rewound pups in my jazz bass. These are Fralin pups rewound to aprox. 6-7K.
Everythings great and quiet when both pups are full opened or at same position. But with only one pup, or one of the pots slightly turned up or down, I get a horrible buzz. It's very anoying. Would the shielding help?
Thanks very much.
 
#177
Tihi said:
Hi there
Just a beginners question.
I've installed recently some rewound pups in my jazz bass. These are Fralin pups rewound to aprox. 6-7K.
Everythings great and quiet when both pups are full opened or at same position. But with only one pup, or one of the pots slightly turned up or down, I get a horrible buzz. It's very anoying. Would the shielding help?
Thanks very much.
Click to expand...
Yes, but as long as you use single-coil pickups, you will get that hum... though sometimes more than others depending on your environment. A really really good shielding job should reduce the hum to a very tolerable level, but if that isn't good enough (again, depending on how "rude" the clubs are you play in), humbucking pickups are the only further step you can take.

Also, next time you're in a club like that, try turning off all the neon signs around the stage, and look for any dimmers that you might be able to turn all the way off (no, not all the way down or even all the way up... while that does help, the only way to remove it's effect is to have it SWITCHED off.)

Age-old classic single-coil issue. :)

Hope this helps.
 
#179
Nick Ioannucci said:
i have a question about connecting the cavities, ive actually done this 3 times now, but have never connected the cavities because i dont have the 8" tape, just a big ol roll of 2" will it make a significant change or not really? i have some braided shield wire that i can put in, ive just been waiting till a string change to do it.
Click to expand...
I connected the cavities using the braid in shielded wire I bought to replace the bare wires that came on the pickups. However, I can't tell you exactly how much it helped because I did it all at once. I do think it should be worth it, though, otherwise, any shielding you put under/around the pickups isn't really doing much.

Remember, the reason why shielding works, is because it basically takes electrical interference, and "shorts it to ground" as it attemps to pass through the shielding. You might benefit some by just having the foil there in the cavities without grounding it, but in theory, it shouldn't be nearly as effective.
 

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