"Flatpups" pickups?

[elmar flatpup]

Jason, what encouraged me first was my unwillingness to cut holes in my cigarbox guitars. Then, and most important, the highly positive feedback of fellow hobby builders who became frequent buyers. Only recently; the Flatpup pickups get more attention from reso-guitar players. I do not make too much effort to spread da word - customers are better in that :-)

[Jason Rodgers]

Then the word is working. A friend commented on one of my facebook guitar construction pictures and mentioned your pups. A quick google and a search here on the forum led me to post this discussion. Glad we've all convened here. We have things to learn from you.

[Martin Beer]

I have a pre-war Kalamazoo KG-21 I've been trying to build a pickup for, for years, without a great deal of success. It has about 5/16 clearance between the strings and body up at the end of the fingerboard. Something like this might be just the ticket.

I have exactly the same guitar and the same situation! I managed to wind a couple of things that sounded tolerable, albeit with low output but I never got the physical construction well enough sorted for the pickup to hold together in the longer term. Right now I have a Schaller 10/44 on a bracket mounted to the pickguard, but it's closer to the bridge than neck and sounds more danelectro than jazz-box.
Looking at the price of these I'm sort of tempted to just contact the chap and order one rather than pursue the DIY angle any further...

[David King]

Yes the prices are outstanding.

[elmar flatpup]

Please note that I don't advertise here since I don't run a company. From the technical point of view, you might be interested in the above mentioned "poleShades". The output of the b- and e-strings of acoustic bronze string sets can be adjusted by shifting the magnets:

... and the very recent prototype as floating version:

The pickup can be extracted to adjust the poleShades

[Jason Rodgers]

Now that is just plain tricky. And it's just another opposing magnet that sort of gets in the way of the main pole?

Feel free to put on the brakes if questions are prying too deeply into your product, but what sort of DC resistance do you aim for? Do you have different values for 1, 2, 3, and 4+ string pickups? This is probably the R&D that you have done to arrive at products that you feel confident selling, so it's understandable if you'd want to withhold that information.

[elmar flatpup]

the poleShades kinda "catch" the magnetic field lines, preventing them from taking a larger distance towards the strings. Just like a pot divides the current and send one part to ground. This might not be scientific but figurative for me to understand.

The Flatpup idea grew in the diy environment of cigarboxguitar builders. The no-rule approach helped a lot to experiment and find out new things

[Mike Sulzer]

the poleShades kinda "catch" the magnetic field lines, preventing them from taking a larger distance towards the strings. Just like a pot divides the current and send one part to ground. This might not be scientific but figurative for me to understand.

The Flatpup idea grew in the diy environment of cigarboxguitar builders. The no-rule approach helped a lot to experiment and find out new things

You are describing a visual way of interpreting the effect of a high permeability material. Strong magnets such as neo are low permeability. They are a strong source of magnetic field, which can add to or subtract from the permanent field that reaches the string from other sources, altering the degree of magnetization. When you change how much the string is magnetized, you change how much time varying flux passes through the coils

[Jason Rodgers]

No rules? Hey, that's how I like to play!

[madzub]

i made a couple pickups just like this for a 7 string guitar i made a few years ago that had very little room between strings and body, and being a 7 string with wide classical spacing, it needed to be extra long too. Simple design, a piece of sheet metal, wrapped a layer of clear tape around it for isolation, then two sidewinder coils of about two thousand turns of 44awg wire, and a line of very small neo magnets in the middle. The whole thing was only a few millimeters tall, sounded great with standard output.

I thought about marketing the idea as it was thinner than anything else i was able to find and easily adaptable to 8 or 9 or any number of strings, just use a longer piece of sheet metal. different types of metals to change the tone, more or less wire, different magnet structures... and it'll fit on any guitar without modification. but i'm too lazy to do that, so good for you Elmer!

[elmar flatpup]

Given the simplicity of design, I was surprised that I couldn't find similar pickups on the internet. I shared my findings with other builders rather than keeping them ;-)

[rjb]

No rules? Hey, that's how I like to play!

This is only a guess, but I suspect the laws of physics may apply even to cigarboxguitar building.

[Jason Rodgers]

This is only a guess, but I suspect the laws of physics may apply even to cigarboxguitar building.

Ok, FINE, but no more!

[Martin Beer]

Well, I've got mine and it solves the problem of getting a neck pickup on my Kalamazoo archtop without cutting holes, which I'd been trying to figure out for about five years now!
The pickup is an interesting lesson in not making assumptions about the sound of a pickup from its DC resistance, as it measures less than 3K but sounds warm and mellow. I guess this would be because it's seeing a fairly wide section of the string, but it has a definite humbucker quality about it while still retaining decent definition. It's not noisy either, even without a string ground.

[rjb]

...it measures less than 3K but sounds warm and mellow. I guess this would be because it's seeing a fairly wide section of the string...

Did you get the MR model?
If so, maybe the aluminum pickup ring also mellows the tone(?)