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Vintage threads from the first ten years

Re: Atchley's

6/13/1999 9:11 PM
Hi	Re: Atchley's Interesting ideas, both the copper foil for stained glass and the BOSS device. I have to admit the individual coil shielding with teflon tape and copper foil over it seems like the overall best idea, except for just putting up with whatever level of hum (sometimes it may be a little difficult, though, especially in bars with those neon advertising signs hung everywhere and flourescent lights over the pool tables, you know the place. Same place where the drunk always shouts, "Play that song.. You know, that song... That song I like so well...") DiMarzio suing Kinman over his pickups? That almost proves the Kinmans are better! Didn't DiMarzio try to copyright the term "PAF" for pickups a couple of years ago? These guys! And yes, John Atchley's website is full of great ideas, whatever the result of body-cavity shielding. I don't really know who he is, but he's a sharp guy, obviously. But the best thing I've come up with for dealing with the noise is make sure the ground is good, make sure you haven't made repeated ground loops while trying to kill the noise, and use good shielded cables. Although sometimes I use cables that are less well shielded (looking for different tones for different things), live I use them for fx loops or from the last device in an fx chain to the amp. I might use a smaller cable from the guitar to the first box (or directly to the amp), usually it sounds cleaner and clearer. But I've had as good or better results from well shielded cables than from shielding the guitar. Hi

6/13/1999 9:11 PM

Re: Atchley's

Interesting ideas, both the copper foil for stained glass and the BOSS device. I have to admit the individual coil shielding with teflon tape and copper foil over it seems like the overall best idea, except for just putting up with whatever level of hum (sometimes it may be a little difficult, though, especially in bars with those neon advertising signs hung everywhere and flourescent lights over the pool tables, you know the place. Same place where the drunk always shouts, "Play that song.. You know, that song... That song I like so well...") DiMarzio suing Kinman over his pickups? That almost proves the Kinmans are better! Didn't DiMarzio try to copyright the term "PAF" for pickups a couple of years ago? These guys! And yes, John Atchley's website is full of great ideas, whatever the result of body-cavity shielding. I don't really know who he is, but he's a sharp guy, obviously. But the best thing I've come up with for dealing with the noise is make sure the ground is good, make sure you haven't made repeated ground loops while trying to kill the noise, and use good shielded cables. Although sometimes I use cables that are less well shielded (looking for different tones for different things), live I use them for fx loops or from the last device in an fx chain to the amp. I might use a smaller cable from the guitar to the first box (or directly to the amp), usually it sounds cleaner and clearer. But I've had as good or better results from well shielded cables than from shielding the guitar.

Hi

6/14/1999 0:12 AM
anonymous	DiMarzio also owns a patent on double cream humbuckers (I thinkit's double cream, or maybe white), preventing any other manufacturer from producing them... Now that's too bad since we all know double cream sounds better... ;o)

6/14/1999 12:00 PM
GFR	Are you crazy? Zebra pickups rule!

6/14/1999 1:52 PM
MJ Harnish	Ok, you've got me. I actually have a black/creme zebra Duncan JB in my LP....

6/14/1999 1:29 AM
AMZ	There is a type of tape that you apply then heat and it will shrink to about 1/2 its previous size. That could possibly be used for a very tight seal. I have used it numerous times on wire connections. regards, Jack Orman

6/14/1999 9:33 PM
Steve A.	Jack: At least in the past Radio Shaft used to sell heat shrink tape (I guess for people who forgot to slip on a piece of tubing before soldering up the joint!) I'd recommend putting the teflon tape under it just be safe... Steve Ahola

6/15/1999 5:16 PM
Mark Hammer	Hmmm...not so sure I like this current format, but here goes. You wire in a dummy like a regular pickup in parallel, making sure that the dummy coil is phase-reversed with respect to the true coil. You can do this by swapping the leads of the dummy until you find the arrangement that produces the least hum. I suspect one of the primary reasons why the dummy coil thing never really caught on was because they have to GO somewhere, and there usually aren't a lot of places where they could go. But we can invent places. I stuck a dummy coil in the control cavity of a friend's Tele once. It was hardwired to the pickup switch so that it was always "on" in parallel with whatever pickup was selected. It was no panacea for hum but it helped. Several caveats have to be considered, though. Dummy coils work by matching the true coils, turn for turn. The less matched, the less the cancellation. This reduces cancellation when you tack a dummy coil on top of two or more single coils; best cancellation occurs when you have one dummy and one pickup. They also work by picking up RFI and hum at roughly equivalent amplitudes, which means that if they don't have equivalent "access" to the noise source, the cancellation is reduced. This is one reason why the control cavity location was convenient but not optimally effective. In this latter case, the control plate provided shielding that reduced what the dummy coil could pick up, and since they were spaced apart (and oriented at right angles on both the horizontal and vertical axes) the pickup and dummy coil were rarely picking up the noise source at equivalent amplitudes. So there was not a perfect match, and the cancellation was only modest. As a coil, a dummy would still have some inductance, and this would be placed in parallel across the volume control. I have rarely seen any information on how this might affect the sound. There is a cost to shielding pickups, so I suspect there is also a possible tonal cost to dummy coils. Having said that, there are many ways to get the same inductance, and since (I think, correct me here guys if I'm wrong) a lower DC resistance coil in parallel with the pickup could have the hum-cancelling effect with minimal colouration (pardon the Canadian spelling), the coil winder is free to use thicker gauge wire (e.g., #38-40), which is generally easier to work with, not to mention easier to find, and cheaper to buy. It may even be possible to wind a dummy coil and slide it under an existing single coil. Ideally, though, I would think that routing out a shallow bed for a dummy coil in between the front and middle pickup would let you stick one under the pickguard, where the user would be assured of pointing both the true coil and the dummy at the same noise source when they play. Bear in mind that a half-inch might be fine for depth since you don't need room for polepieces or mounting screws/hardware, just room for a coil. As always, I endorse the scouting of repair shops for cheap pickups removed to make way for good ones, or humbuckers with a single torn coil sitting beside a good one. You don't care about the tonal quality, all you care about is an untorn coil of about the right number of turns. Gently remove the polepieces (if there are any to take out), and wire it up. If that fails, get yerself a mu-metal 10-gallon hat to shield away the flourescent noise, and a mu-metal amp cover to shield the transformer noise.

6/15/1999 5:16 PM

Mark Hammer

Hmmm...not so sure I like this current format, but here goes.

You wire in a dummy like a regular pickup in parallel, making sure that the dummy coil is phase-reversed with respect to the true coil. You can do this by swapping the leads of the dummy until you find the arrangement that produces the least hum.

I suspect one of the primary reasons why the dummy coil thing never really caught on was because they have to GO somewhere, and there usually aren't a lot of places where they could go.

But we can invent places. I stuck a dummy coil in the control cavity of a friend's Tele once. It was hardwired to the pickup switch so that it was always "on" in parallel with whatever pickup was selected. It was no panacea for hum but it helped.

Several caveats have to be considered, though. Dummy coils work by matching the true coils, turn for turn. The less matched, the less the cancellation. This *reduces* cancellation when you tack a dummy coil on top of two or more single coils; best cancellation occurs when you have one dummy and one pickup. They also work by picking up RFI and hum at roughly equivalent amplitudes, which means that if they don't have equivalent "access" to the noise source, the cancellation is reduced. This is one reason why the control cavity location was convenient but not optimally effective. In this latter case, the control plate provided shielding that reduced what the dummy coil could pick up, and since they were spaced apart (and oriented at right angles on both the horizontal and vertical axes) the pickup and dummy coil were rarely picking up the noise source at equivalent amplitudes. So there was not a perfect match, and the cancellation was only modest.

As a coil, a dummy would still have some inductance, and this would be placed in parallel across the volume control. I have rarely seen any information on how this might affect the sound. There is a cost to shielding pickups, so I suspect there is also a possible tonal cost to dummy coils.

Having said that, there are many ways to get the same inductance, and since (I think, correct me here guys if I'm wrong) a lower DC resistance coil in parallel with the pickup *could* have the hum-cancelling effect with minimal colouration (pardon the Canadian spelling), the coil winder is free to use thicker gauge wire (e.g., #38-40), which is generally easier to work with, not to mention easier to find, and cheaper to buy. It may even be possible to wind a dummy coil and slide it under an existing single coil. Ideally, though, I would think that routing out a shallow bed for a dummy coil in between the front and middle pickup would let you stick one under the pickguard, where the user would be assured of pointing both the true coil and the dummy at the same noise source when they play. Bear in mind that a half-inch might be fine for depth since you don't need room for polepieces or mounting screws/hardware, just room for a coil.

As always, I endorse the scouting of repair shops for cheap pickups removed to make way for good ones, or humbuckers with a single torn coil sitting beside a good one. You don't care about the tonal quality, all you care about is an untorn coil of about the right number of turns. Gently remove the polepieces (if there are any to take out), and wire it up.

If that fails, get yerself a mu-metal 10-gallon hat to shield away the flourescent noise, and a mu-metal amp cover to shield the transformer noise.

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