piccard
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Post by piccard on Jun 11, 2008 12:49:50 GMT -5
Hi all.
Sorry if this has been covered...I searched but did not find the answer.
Is there a signifigant difference in noise reduction with relation to the thickness of shielding material?
Will layering copper shielding tape to build the thickness be effective? if so, does the adhesive between layers need to be conductive as well?
Recommendations? 1.5 mil, 4 mil or 10 mil (copper).
Thanks.
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Post by D2o on Jun 11, 2008 13:36:30 GMT -5
Hi Piccard!, and welcome to the show!
Perhaps more important than thickness is electrical and magnetic continuity ... without "metal-to-metal" contact, it's not going to be very effective shielding.
For example, if you put layers of tape in there and it's adhesive-to-metal, it will be better than nothing. But if you ensure that all of the pieces have "metal-to-metal" contact with other it will be susbtantially better.
As for layers or thickness, one layer of properly installed shielding should be fine. It's an electromagnetic shield, not insulation.
I have put two layers before, but not more ... I think you'd risk cooking up some kind of eddy stew or something if you go overboard.
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piccard
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Post by piccard on Jun 11, 2008 15:02:17 GMT -5
Hi Piccard!, and welcome to the show! Perhaps more important than thickness is electrical and magnetic continuity ... without "metal-to-metal" contact, it's not going to be very effective shielding. For example, if you put layers of tape in there and it's adhesive-to-metal, it will be better than nothing. But if you ensure that all of the pieces have "metal-to-metal" contact with other it will be susbtantially better. As for layers or thickness, one layer of properly installed shielding should be fine. It's an electromagnetic shield, not insulation. I have put two layers before, but not more ... I think you'd risk cooking up some kind of eddy stew or something if you go overboard. Ok, thanks. I was considering 4 mil adhesive backed copper shielding tape. I read where someone had layered their installation.....made sense, but i figured - what's the purpose if there is adhesive between the sheets? which led my next question.....is thicker shielding necessary? I tend to overdo things. I will stick to 1 layer 4 mil. Thanks. |
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Post by D2o on Jun 11, 2008 15:21:55 GMT -5
You are welcome! To be clear, there is nothing wrong with layering, so long as the top layer is all connected - for example, you would just fold the edge of each new copper tape/sheet under itself so that you end with copper, not adhesive, contacting the previously installed copper tape/sheet. With respect to actual thickness, think of it this way: you want copper that has a thickness along the lines of heavy duty aluminum kitchen foil (which you could actually use, as well EDIT: "instead" (i.e. you must use one or the other) - but copper is best). That way it is durable, but also pliant enough that you can actually "use" it ... if you go with too thick a material it's just a pain in the butt. By the way, I am currently shielding an incredibly rare strat-like instrument (i.e. it's so cheap rare, no one has ever heard of it ... or at least admitted it) with aluminum duct tape (not metallized duct tape). It's not as good as copper, but it still does the trick, and is cheap, easy to find, and easy to work with. Whatever the material, it's the method that counts at least as much. Let us know how it turns out!  |
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Post by newey on Jun 11, 2008 18:29:52 GMT -5
DD- I don't know that we're being particularly clear. You are talking of folding and overlapping the edges of a single layer of shielding foil/tape. This is a good way to assure continuity if'n you don't buy the fancy copper tape with the conductive adhesive. But Piccard was proposing multiple layers of tape to build thickness, which, to be clear, he need not do. Piccard, one layer is it, overlap the edges metal-to-metal as DD suggests, and follow the QTB directions (follow the link at the top of this page). Whether you use the safety capacitor is up to you, it's a good idea if you're a tubehead (or if you may become one at some future date).  |
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piccard
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Post by piccard on Jun 12, 2008 21:42:36 GMT -5
DD- I don't know that we're being particularly clear. You are talking of folding and overlapping the edges of a single layer of shielding foil/tape. This is a good way to assure continuity if'n you don't buy the fancy copper tape with the conductive adhesive. But Piccard was proposing multiple layers of tape to build thickness, which, to be clear, he need not do. Piccard, one layer is it, overlap the edges metal-to-metal as DD suggests, and follow the QTB directions (follow the link at the top of this page). Whether you use the safety capacitor is up to you, it's a good idea if you're a tubehead (or if you may become one at some future date). I understand....but thank you for the clarification. I will stick with a single layer and see what happens. I am getting tone pot noise (lace sensors installed) in my Strat Ultra. I also have the same noise present in my Anderson Cobra, I'll probably work on it once the strat is done. I am going to install the cap....I am currently working with something other than tubes- but it's only a matter of time before I'm searching out NOS again. Thanks for your help. |
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Post by newey on Jun 12, 2008 22:32:15 GMT -5
PCD-
The odds are long that 2 different guitars would both develop the same "tone pot noise". If you're getting the same noise out of 2 guitars, I'd be looking to eliminate the amp and/or cable as possible sources.
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piccard
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Post by piccard on Jun 13, 2008 21:46:45 GMT -5
well, shielding is my last resort before doing so. I have been chasing this noise issue for awhile. I have replaced all my cables at least 3 times, swapped out the preamp I am running thru, changed power amp and cabinet....everything I have tried has the same end result. The noise I hear is an electrical buzz, augmented in volume when I roll the tone pot to the treble side (both guitars same condition.) In fact, I first noticed the noise in the Anderson about 2 years ago (different amp set up than current), it was so bad I thought the pot was going bad. So i had it replaced. When i went to pick it up the tech played it for me...same buzz. When I pointed it out to him, he said....oh that? They all do that! I've played a few guitars in my day......they most certainly are not supposed to do that! lol.. Anyway, the strat is newer to me and it has the same issue- I did all the gear swapping mentioned above after getting the Strat. Besides being the last resort, shielding makes sense to me based on what I've read here and QTB. Interestingly enough, if I stand in the right spot- the buzz goes away, but anywhere near a component or light switch and i am totally distracted by the noise. In fact, one night recently while practicing, I leaned up against a wall that had metal studs in it....same as if I were near an electrical switch. Really strange. Parts are on order. I have my fingers crossed. I really have no idea what I'll do if this doesn't solve the issue.. perhaps I've got a a new rig and new guitars in my future  |
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Post by D2o on Jun 14, 2008 10:01:45 GMT -5
Piccard, Based on your last post, it sure sounds like shielding should be your first resort. Once you do it, you will never not do it again. Trust me on that. |
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piccard
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Post by piccard on Jun 15, 2008 22:35:05 GMT -5
it should have been, but I was chasing the wrong problem....I too thought the odds were too high to be poor shielding in two guitars.....
No worries, I think I'm on the right track now. My materials are starting to show up. I should be ready in a few days to do the mod on QTB. I'll post the results when I'm done...really looking forward to it.
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astro1176
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Post by astro1176 on Sept 10, 2008 20:06:50 GMT -5
...you want copper that has a thickness along the lines of heavy duty aluminum kitchen foil (which you could actually use, as well EDIT: "instead" (i.e. you must use one or the other) - but copper is best). ... I was thinking of shielding my guitar with a layer of aluminium tape and a layer of copper - to get the benefits of both types of shielding (copper has better conductivity, but aluminium is apparently much much better at blocking the interference from dimmer switches). I have heard, and see above, that some people think it is a ba idea to mix different metals in shielding. Why? What will happen? Thanks for any info on this matter |
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Post by ChrisK on Sept 10, 2008 22:25:46 GMT -5
The benefits of any shielding layer is dependent on the shielding layer being a contiguous electrically conductive shielding layer.
In other words, ALL pieces of said layer must be in electrical contact with each other AND the required connection to signal ground.
That being said, aluminum is quite difficult to interconnect with other pieces of aluminum and any other shielding, other than thru mechanical force and/or surface treatments that ensure non-oxidation.
Soldering aluminum is an art and not generally able to be done on thin layers.
Mixing dissimilar metals can lead to corrosion.
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