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Help With Grounding On An Aluminum Body Guitar


ApolloSpeed
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Hey guys, I just completed my project solid aluminum body guitar. It really sounds pretty good too. I'm using a Duncan JB, one 500k volume, and that's it. Pretty simple setup.

But I think I might need some grounding advice. The guitar sounds good on a low watt combo amp. But when using my 5150 halfstack. It has a harsh squel when you mute the strings. Even with a BOSS NS2 inline.

My question is, do i need some special shielding or a special grounding technique when having a guitar body made outta aluminum ?

thanks,

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So you have 1 pikup conected directly to the volume pot, then the pot directly to the jack. No switch etc. if so you need to run a wire from the trem claw (holds the springs in the trem cavity) to the back of the volume pot, then 1 fromt he back of the volume pot to the ground side of your jack and also all the grounds of the JB need soldering tot he back of the volume pot. Then see if the sound is any better.

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Hmmmm...All metal components have to be grounded...only once. If both the pickup and volume pot are in physical contact with the aluminum body AS WELL AS conventional grounding by wires then you might just have a ground loop occurring. You haven't mentioned what sort of grounding setup you've installed so far, type of bridge / how its mounted and whether or not your guitar has a trem. Is there a pickguard ? if so, of what material and whats mounted on it? Share that info and we might be able to work the grounding out.

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Hmmmm...All metal components have to be grounded...only once. If both the pickup and volume pot are in physical contact with the aluminum body AS WELL AS conventional grounding by wires then you might just have a ground loop occurring. You haven't mentioned what sort of grounding setup you've installed so far, type of bridge / how its mounted and whether or not your guitar has a trem. Is there a pickguard ? if so, of what material and whats mounted on it? Share that info and we might be able to work the grounding out.

There is no pickguard. Everything is back routed. The volume pot and pickup and bridge are mounted directly to the aluminum body. I'm using this Hipshot babygrand bridge...... 5846_1sm.jpg

I currently have the red/white JB wired taped together. The JB green/braided wires soldered to the volume case. The black to the left volume leg. The input jack to the center leg. And a ground from the volume case to the input jack. And the right leg is grounded to the case as well.

Anything else I should do, or undo ? :D

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You can't get any better shielding than a solid lump of aluminium :D Provided you have continuity between the ring of the output jack and somewhere on the body, trust me, it's well shielded!

I was going to suggest a microphonic pickup.

'Course it could be the amp?

Can you make the squealing come and go if you back off the volume control?

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You can't get any better shielding than a solid lump of aluminium :D Provided you have continuity between the ring of the output jack and somewhere on the body, trust me, it's well shielded!

I was going to suggest a microphonic pickup.

'Course it could be the amp?

Can you make the squealing come and go if you back off the volume control?

I will the backing off it and see what happends, and I could check the continuity.....

I know it is not the amp.....cause my ibanez is fine through it.

I also have a spare emg81 laying around too.....I could try that and see if there is any difference. :D

Edited by ApolloSpeed
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OK, consider your bridge as just part of the body, ie. in physical contact thru the mounting studs. You have to isolate one of the components, either pickup or vol pot, from the body. You have more than one ground contact for the body causing a loop. I'm not sure if this will solve the problem but its best to set this part right, just to rule it out. You say the pickup is mounted directly to the body, is that through the adjustment screws that screw into the dogears? Or is there a pickup mounting ring? A non-metal mounting ring will isolate the pickup from the body. This way the body can only be grounded thru the physical contact with the volume pot. If there is no way to isolate the pickup (already grounded via wire to vol pot casing) then use rubber or nylon washers on the vol pot, both sides so it won't touch the body when mounted.

Edited by Southpa
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OK, consider your bridge as just part of the body, ie. in physical contact thru the mounting studs. You have to isolate one of the components, either pickup or vol pot, from the body. You have more than one ground contact for the body causing a loop. I'm not sure if this will solve the problem but its best to set this part right, just to rule it out. You say the pickup is mounted directly to the body, is that through the adjustment screws that screw into the dogears? Or is there a pickup mounting ring? A non-metal mounting ring will isolate the pickup from the body. This way the body can only be grounded thru the physical contact with the volume pot. If there is no way to isolate the pickup (already grounded via wire to vol pot casing) then use rubber or nylon washers on the vol pot, both sides so it won't touch the body when mounted.

yes the pickup is mounted to the aluminum with screws into the dogears, so it's grounded. So you think I might have a ground loop huh? Currently I don't have a ground wire from the vol. case to the bridge, but I don't need one right? I should just insulate my vol. pot from the aluminum body, and then I should ok?

Edited by ApolloSpeed
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There is plenty of info on the web about ground loops and grounding in general.

Here are a few examples:

http://www.aqdi.com/groundloop.htm

http://www.harmony-central.com/Guitar/Faqs...q.grounding.txt

I'm really curious to see if isolating the volume pot will do the trick. Please share your results. Ground loops cause a difference in voltage potentials in the grounding system. The result is excess noise, eg. 60 cycle hum.

There is also info in the forum archives.

Maybe Lovekraft can help you out. He may have passed on a few months ago but I'm sure hes answered every question concerning electrical wiring at least once. Sure wish he was still around. :D

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what are the differences in symtoms of ground loops verses not a good ground at all ??

No ground - it won't work at all, not even through your smaller amp, you'll just end up with a whole heap of noisy garbage.

No shielding - guitar will pick up lots of hum through any amp.

Ground loop - could cause all sorts of things - hum, buzz, high pitched oscillation, radio pickup. Southpa's comments regarding making contact with the shileding at one point only are valid, although I would've thought that with a solid aluminium body guitar the chances of causing such a loop would be pretty minor - an earth loop requires two or more points earthed at different locations and a degree of resistance in the earth connection to cause anything audible - a solid piece of aluminium the size of a guitar body will have a pretty damn low resistance! :D Still, I'd be curious to see if his suggestions have an impact - go for it!

Something else which just struck me - you've got a solid aluminium bodied guitar with a highly inductive (your pickups) circuit located inside, coupled to a very high gain amp (your 5150). I wonder if by using aluminium as your body material you've inadvertantly created a resonant circuit, like a radio receiver? It could be that by choosing aluminium as your body material you've added too much capacitance to the circuit and it'll oscillate when you apply too much gain :D For your sake, I hope not!

Basically you may have too much "earth"!

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  • 2 months later...
Thats good news. Whats did you use as insulators? Btw, got any pics of this aluminum guitar of yours? and how did you construct it? CNC from a billet? or?

Sorry I'm just now getting back....

I used rubber o-rings for insulators...hahah!

I got a website for the guitars here.... www.660guitars.com There is an audio clip and pics....the pics are a little dated, as my next revision has some very small changes. But these pics are still VERY close.

I made with a CNC and used T6061 alumium.

THANKS!

Drew

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Thats good news. Whats did you use as insulators? Btw, got any pics of this aluminum guitar of yours? and how did you construct it? CNC from a billet? or?

Sorry I'm just now getting back....

I used rubber o-rings for insulators...hahah!

I got a website for the guitars here.... www.660guitars.com There is an audio clip and pics....the pics are a little dated, as my next revision has some very small changes. But these pics are still VERY close.

I made with a CNC and used T6061 alumium.

THANKS!

Drew

my god.. what a beautiful guitar and playing.. very metal.. very Slipknot-ish...

how much was it for the T6061?

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Thats good news. Whats did you use as insulators? Btw, got any pics of this aluminum guitar of yours? and how did you construct it? CNC from a billet? or?

Sorry I'm just now getting back....

I used rubber o-rings for insulators...hahah!

I got a website for the guitars here.... www.660guitars.com There is an audio clip and pics....the pics are a little dated, as my next revision has some very small changes. But these pics are still VERY close.

I made with a CNC and used T6061 alumium.

THANKS!

Drew

my god.. what a beautiful guitar and playing.. very metal.. very Slipknot-ish...

how much was it for the T6061?

Thanks!

The aluminum is about $100 per 12"x18"x1" block.

Yeah the clip is real basic, just an SM57 on a vintage 30 speaker running a 5150 amp. No trick studio stuff. Just raw tone!!

My revised guitars will feature custom Warmoth necks.....far better than the cheapy Ibanez chinese neck that was used on the recording.

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Thanks!

The aluminum is about $100 per 12"x18"x1" block.

Yeah the clip is real basic, just an SM57 on a vintage 30 speaker running a 5150 amp. No trick studio stuff. Just raw tone!!

My revised guitars will feature custom Warmoth necks.....far better than the cheapy Ibanez chinese neck that was used on the recording.

chinese neck or not the guitar f-ing rocks!

are you using a drum machine or is that a band? just curious...

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Thanks!

The aluminum is about $100 per 12"x18"x1" block.

Yeah the clip is real basic, just an SM57 on a vintage 30 speaker running a 5150 amp. No trick studio stuff. Just raw tone!!

My revised guitars will feature custom Warmoth necks.....far better than the cheapy Ibanez chinese neck that was used on the recording.

chinese neck or not the guitar f-ing rocks!

are you using a drum machine or is that a band? just curious...

yes, I programmed the drums. I will also be posting a clean guitar clip too.....after I build the revised version guitar.

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