Here's the breakdown. Guitars with humbucking pickups have two single coils side-by-side, and wired to cancel out hum from electrical interference, namely the 60hz beast within our homes. The humbuckers are known for a slightly higher output (two coils), but at the expense of an upper high bite that single coil pickups are known for. The orignal Gibson P-90 (soapbar) pickups, and your standard Fender pickups are single coil - and retain a lovely chimey high-end. The cost? They do not cancel out hum and noise. All is not lost, though. You can shield the guitar's pickup and control cavitities and knock out 95% of outside hum.
Shielding a guitar is not just something that should be done to single-coil guitars, though. My 1979 Les Paul is amazingly shielded. The control cavity, pickup-selector, and even output jack, are all enclosed in metal cases. Only shielded wire goes from one area to the next. It is amazingly quiet. So much so that when I pick up someone else's guitar, and hear the hum, I think "how can they stand that?" So, why don't all guitars, especially single-coil guitars, have this shielding done at the factory? Two reasons: tone, and cost. Some people claim that they lose a tiny bit of top-end chime on their guitars when shielded. As for cost, well, you know the standard business model - find that price point, and sell it.
As for tone, I grant that people trust their ears and do hear a slight difference. To some people, a slight difference is huge. Eric Johnson makes statements about what battery brand he puts in his guitar effects (and note that he thinks the batteries sound better when they are "worn in" a bit). I would hate to be that guy's guitar tech. He's the type of player that is amazingly brilliant when playing, and has no clue what he is talking about when he is not playing. (I like the guy, and his music, but he claims that a different electrical cord powering his amps will have an effect on his tone --> audiophool!).
From this angle, you can see that I shielded the control cavity, and the neck and middle pickup cavities. You can't see this, but underneath the bridge is another cavity that is totally shielded. I bought a roll of copper foil from StewMac and took my time to not have too many pieces, or creases, in my shielding. For one reason, I don't want this to look like garbage, even though anyone would rarely even see this part of the guitar. The second reason is that the edges of the foil will be soldered to make sure that there is complete continuity in the ground here. Basically, I want to make sure that there is little resistance across any point in this grounding scheme (as close to 0-ohms as possible). If there is a gap, or not a good connection between two pieces of foil, then you could create a separate potential for voltage. In short, you just created a ground loop! It would sound as bad, or worse, than if you hadn't messed with it at all.
In this shot you can see the soldered edges a little better. Soldering has a second advantage as well. Heating up the copper foil to make a good connection also makes the adhesive back hold a little more, since it is kind of cool this time of year in my workshop. Note, following GuitarNuts's advice, the shielding of the cavities lips over the edge. This is because a big strip of shielding will be placed on the underside of the pickup cover and will encapsulate all of this as one connection. You can also barely see that there is a small bit of shielding from the control cavity that comes up just shy of the screw hole. That will connect the shielding to the metal control plate and have everything shielded as much as possible.Some notes on this build that I don't have pictures of:
- I did not show this, but I have already mounted the neck and middle pickups to the body of this guitar for fit. This is not easy, because the placement of the neck pickup is determined by the hole in the pickguard. Some pickups are mounted to the pickguard (easy) and some to the body (harder). I want mine mounted to the body because it looks cleaner (less holes in the pickguard) and it allows the pickguard to come off to adjust the pickup height and the neck's truss rod.
- I took a bit of time cutting the middle pickup hole in the pickguard. I did not photo-document this process at all. Basically, with the pickups set in the body, it was a matter of laying the pickguard on the body and pickups repeatedly, and filing the hole for this middle pickup. The result is such a good job that many may not believe I did it. I guess that is the effect I was going for...
- Okay, now is the time that I need come clean about these pickups. I chickened out on the single-coil hum. If you buy an American Deluxe Telecaster or Stratocaster, they will come with some Fender SCN noiseless pickups. This is done by stacking pickups up, and using rare-earth magnets (samarian cobolt). Some people complain that these are not true single-coils and that they don't sound like single-coils. Well, I went another route, and chose Seymour Duncan vintage stack pickups for the neck and bridge, and a Strat classic stack pickup for the middle. In short, stacked means a hybrid humbucking pickup, stacked on top of each other to get characteristics of single-coil pickups. A tone hound will be able to tell that these are not true single-coil pickups.
- Tone-hounds who love single coils often state that the hum doesn't matter as soon as the song starts. Well, I agree with that, but the hum bugs me so much the rest of the time. Besides, I counter that statement that your pure guitar sound will be lost in the mix once you play with other instruments, and your amplifier is mic'ed through the PA system. So, I chose noiseless, get over it.
--gh
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