Curved pickups? WTF?

[Mark Hammer]

A work colleague told me his soundhole pickup was giving him some grief and humming, so I asked him to bring it in and I'd take a look at it. I wasn't quite prepared for what I saw: a "blade" pickup, curved in a parenthesis-like curve to nestle up against the part of the soundhole closest to the neck. He doesn't know the make of the pickup and there are no identifying marks on it. Since the sructure is held together by "security" bolts, I'm unable to take it apart and see the bare coil.

How in heaven's name do you wind a curved pickup coil? Or is it likely to be like some of those whacko Goya pickups I used to see in V shapes where several separate coils would lie inside the pickup cover? What stymies me is the fact that it is a blade pickup and that the shape of the package pretty much precludes use of 2 or even 3 separate coils on, say, plastic bobbins slipped over a less blade-like base of the blade.

Man, this is a real head-scratcher.

[David Schwab]

Do you know what brand it is? I've never seen this before.

It's possible they wound the coil on a flexible bobbin, which was then bent to shape when the blade was inserted.

[Mark Hammer]

I'll see if I can find out anything from the store where he bought it.

[mick]

Gibson used curved , or "V" shaped even ,on some of their flying V's ,

[TD_Madden]

yep..Gibson "Boomerang" pickups.....anybody ever taken one apart?

[mkat]

Hi Mark,

If it's a Gibson V Boomerang pickup, then this may be of some help. The text below was extracted from the following link:

http://www.flyingvintage.com/gcmag/V2.html

"V-II Boomerang pickups were not used on any other Gibson guitar. Looking at the underside of these transducers reveal no clues as to their construction because they are potted with a dark compound. [...] Inside the V-shaped black plastic pickup cover are two separate single coils. These appear to be wired in series and out-of-phase for noise immunity. Each coil is assembled with a clear plastic bobbin containing a bar magnet. Both bobbins are taped to a base plate. This plate appears to be a soft, stamped metal in the shape of the bottom end of a hockey stick. Gibson's S-1 guitar pickups resemble these individual bobbins but are larger. Potting may also have been required to hold the bobbins against the top of the pickup cover because the base plate does not allow for screw attachments.

The bass string side coil sits against the back of the pickup cover and is almost perpendicular to the guitar strings. It's coil length covers the three bass side strings (E, A, D). The other coil is situated against the bottom front-side of the cover and has an exaggerated slant as compared to a Stratocaster bridge pickup. This coil covers the treble side strings (G, B, E). With the end of the bass coil pointing into the treble coil one quarter of the way down it's length at about a thirty degree angle from perpendicular, forms the hockey stick with a knob end. Both coils are wrapped with black tape to the baseplate.

Measuring these pickups indicate a high output level, or as players say, these are "hot" pickups. They ranged from 11k to 13k ohms. Sound characterizations are usually subjective, however these guitars have some of the warmth of a Les Paul and a bit of the bite of a Stratocaster. Because they are hot pickups, they tend to be somewhat muddy which is a characteristic of hot, twin-coil humbuckers."

The bottom of the page contains a table listing the different pickups used dating from the 1st issue through to the 2nd generation:

Flying V 1st Issue 1st Reissue 2nd Reissue 2nd Generation
---------------------------------------------------------------------
Production '58-'59 1966-1970 1975-1980 1979 -1982
Pickups PAF Pat. # Decal Pat. # Stamped Boomerang

Regards,

Michael

[madialex]

quite possibly

an air coil, wound on a temp bobbin and slid off and put on the blade, not sure what they did about magnets, possibly one of those flexable ceramic magnets or a series of very small earth mags. I'm guessing it is an air coil by being in the shape it is in. I'm sure Jason has probably seen one, when he comes on he will probably reply, or just PM him.

[kevinT]

pics of

here are some V2s with boomerang shaped PU's. There are some excellent pics and addtional info at: http://www.flying-v.ch/

Of particular interest is the Gallery and Pickup section of the web site.

click on pic for bigger image

[ken]

I spent all day trying to figure out how to make a singlecoil pickup curved...

and was unsuccessful. If you can visualize winding a string around a banana lengthwise, you will see what I mean - the string will go around the convex side of the banana OK, but the string will not follow the concave side of the curve so the coil will eventually assume a 'D' shape.

Ken

[Possum]

can you get pix?

can you get a photo of the pickup? hard to guess without actually seeing it. I bought some NOS boomerang Gibson pickups off Ebay last year, several sets came up for auction. Using magnetic viewing tape you can plainly see the two bar magnets under the cover, the covers are epoxy filled (I hate that), and yes two coils. Never heard these pickups before can't even test them in anything just saving them for posterity, they do look really cool. Wouldn't be too hard to do a curved blade pickup, some kind of air coil up against the blade and properly placed magnet, it could be done....

[David Schwab]

Using magnetic viewing tape you can plainly see the two bar magnets under the cover, the covers are epoxy filled (I hate that), and yes two coils.

They are sort of like Fender P-Bass pickups... only angled. I wonder who designed them? Rick Turner designed a bass for Gibson that had a diamond shaped pickup that had two coils in it like that. He ended up using them on his own basses when the Gibson deal fell through.

They could be a Willi Stich design too. He likes encapsulating pickups in epoxy (the Lawrence pickups use polyester resin).

[Joe Gwinn]

I spent all day trying to figure out how to make a singlecoil pickup curved...

and was unsuccessful. If you can visualize winding a string around a banana lengthwise, you will see what I mean - the string will go around the convex side of the banana OK, but the string will not follow the concave side of the curve so the coil will eventually assume a 'D' shape.

This is the same problem as winding the odd-shaped coils used in electric motors. The standard approach is to wind the coil on a circular former (which could be a ring of headless nails in a piece of plywood), taping the coil with some kind of fabric tape, removing the taped coil from the former and bending the coil to shape while installing in the motor. When all the coils are installed in the motor, the entire assembly is solidified by twice vacuum-dipping it in a kind of varnish and baking it hard. (Solidification is essential in a motor, as otherwise motor vibration will cause the winding wires to rub against each other and wear through their insulating varnish, shorting the motor winding.)

For pickups, one could do much the same thing, except it might be easier to use nylon fishline in a series of knots instead of tape to hold the coil together while it's being installed with the magnet in the cover. Potting is essential, but wax would probably work. I recall discussions of an "air-coil" pickup made just this way, using a ceramic magnet.

[Eric H]

Dang -10 posts about the wrong pickups. Try re-reading Mark's original post.

-Eric

[David Schwab]

Eric, there are a lot of posts here about how to wind a curved coil, and other odd shaped pickups. It is on topic.

We are waiting for more info on the pickup!

Mark, I did a search yesterday trying to find a curved soundhole pickup, and I came up with nothing. I'm really curious about this one! I try to keep abreast on these things, and I honestly can't say I ever heard of this pickup. Does it have a name on it?

[Mark Hammer]

Just got off the phone with the store where he bought it and they were no bloody help. None of the links in the H-C Acoustic Pickup database brings me to my target either (http://www.harmony-central.com/Guitar//Data3/). I'll have to get my buddy to dig around for the packaging at home.