Archtop pickup - custom design.

[StarryNight]

I haven't posted in a while but I thought I'd share a new floating pickup design I did for an archtop. The trick is getting something thin enough to fit between the strings and body. Without designing bobbins from scratch I came up with the idea to use two humbucker slug bobbins together, stick a bar magnet between the slugs at the bottom and stick it all in a humbucker cover that has been shaved down. Unfortunately that wasn't thin enough so I had to go back to the drawing board and came up with the idea of using a combination of slugs and 1/8" x 1/8" neo magnets. I had to cut the slugs to a depth enough to fit the neos in behind the slugs and still be flush with the thickness of the bobbin. In the pics you'll see one bobbin with the slugs facing up and one with the neos facing up. That's because I put them in the wrong way but then I thought, what the hell, and just left them like that. Anyway, that brought the thickness of the pickup to 1/2" which is just low enough on this archtop to fit. The gauss on these little neos read about 200 with the sensor placed above the slug. The sound is pretty clean but full and warm. With jazz the tone gets sucked out with the tone knob half way down most of the time so I figure the tone comes from the fingers and amp in most cases.

[Mike Sulzer]

I believe if you have the neos on top in one case and on the bottom in the other, the field strengths at the strings above the two coils are different. Thus one coil might be contributing significantly more signal than the other. This affects the sound (but not hum cancellation much), especially on the bass strings. Of course, if you have the sound you want, well done!

I haven't posted in a while but I thought I'd share a new floating pickup design I did for an archtop. The trick is getting something thin enough to fit between the strings and body. Without designing bobbins from scratch I came up with the idea to use two humbucker slug bobbins together, stick a bar magnet between the slugs at the bottom and stick it all in a humbucker cover that has been shaved down. Unfortunately that wasn't thin enough so I had to go back to the drawing board and came up with the idea of using a combination of slugs and 1/8" x 1/8" neo magnets. I had to cut the slugs to a depth enough to fit the neos in behind the slugs and still be flush with the thickness of the bobbin. In the pics you'll see one bobbin with the slugs facing up and one with the neos facing up. That's because I put them in the wrong way but then I thought, what the hell, and just left them like that. Anyway, that brought the thickness of the pickup to 1/2" which is just low enough on this archtop to fit. The gauss on these little neos read about 200 with the sensor placed above the slug. The sound is pretty clean but full and warm. With jazz the tone gets sucked out with the tone knob half way down most of the time so I figure the tone comes from the fingers and amp in most cases.
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[StarryNight]

You're right, taking a reading from over the cover the one bobbin has twice the gauss strength as the other. The sound is still quite good, but now I'm curious to match them as I think it would soften the attack somewhat.

[Mike Sulzer]

You're right, taking a reading from over the cover the one bobbin has twice the gauss strength as the other. The sound is still quite good, but now I'm curious to match them as I think it would soften the attack somewhat.

That is what I would expect, most noticeably on the bass strings. Probably better for jazz with them matched, but it is what the guitarist likes that counts.

[jbforrer]

Another idea for thin archtop pickups

Greetings,

Nice work StarryNight. Another idea to consider for a ~1/4" thick floating humbucking pickup.

Shown; 1/4" black plexiglass stock machined to hold two thin bobbins in a cavity. The top surface is left pristine. A thin lip extension on the lower bout fits underneath the pickguard to attach the pickup to the pickguard.

Bobbin flatwork are made from 0.031" PCB stock. Each plate has a machined slot to accept the magnet making the bobbin thickness equal to magnet thickness. The bobbin assembly epoxied to keep all together. Although thin, there is sufficient space to wind good-sounding humbucking coils with #45 wire. The PCB stock is stiff enough to prevent flaring during wind, also offers some screening and solder attach points.

Magnets are 3/16" ceramic bars ... these were chosen after measuring up many samples from different sources. These are weaker than the usual refrigerator magnets. Magnet sets are hand matched to ensure uniformity.

Finally, the cavity is sealed with thin sticky-backed vinyl to protect the delicate contents.

Trust this is of interest.

Regards,
--JBF