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【製作事例】STEALTH JMサイズハムバッカー

[Production example] STEALTH JM size humbucker

This is an example of a special pickup made at Nekodamari Kobo.

You can't see it, but you can hear it? Stealth Pickup

We received an inquiry via our website, and the customer wanted to make a guitar with specifications that required a pickup that is rarely available on the market.

The guitar that inspired this work is the Fender Marauder, a guitar that Fender had planned to release alongside the Jazzmaster and Jaguar in 1964-65 but never produced. This prototype model, called the Type 1, has no visible pickups.

Although all you can see is the large pickguard, there is a pickup built underneath, so it can produce sound like a normal electric guitar; this is known as a stealth pickup.

I have cut out the pickguard for reference, so please try to imagine it from the photo.

Since there are almost no production examples and not much reference data, this was our first attempt, but we judged there to be a high possibility of production, and so accepted the order.

Problem 1: Using a Japanese-made JM type guitar as the base

There are many different pickup specifications, and even the slightest difference means that the pickup will have to be remade or additional processing will be required, in which the guitar is carved into a groove called "recess."

Therefore, we asked the owner which guitar he would like to install it on, or whether he would like to have a new body made, and he expressed his desire to install it on his favorite Japanese-made JM type guitar.

Since the guitar was made to US standards, if I were to make a Marauder guitar at this point, it would not fit without additional processing. Since the total cost of the modification would be high, I made the following proposal.

◆ Manufactured as a stealth pickup that can be mounted without modification according to the dimensions and specifications of the JM size

We didn't want to make a copy of the Marauder, and we thought that if the goal was stealth, it would be better to leave it unmodified, so we went with this suggestion. Here's an example of the shape.

Problem 2: Use of neodymium magnets and production of humbucker specifications

The biggest feature of the Stealth pickup is that the distance between the strings and the pickup is much wider than usual. To solve this, there are two options: increase the magnetic force or increase the output.

After testing, we found that it was possible to create a high-output pickup using a common magnet called Alnico 5, and still produce sound.

If you make a mistake, you might not get any sound at all, or you might get a faint sound like a mosquito, but even with the above specifications, the volume is a little low. Also, the owner wanted something that could be handled with a clean tone. If you use Alnico 5, it will be a high-power specification and will not be easy to handle with a clean tone, so we changed the magnet and switched to a magnetic approach.

We decided to use neodymium magnets, which are familiar in our daily lives and are known as the strongest magnets, to make the instrument. Since this was the first of its kind, we designed it to have a wide magnetic field range in response to string vibrations, to avoid the risk of no sound being produced.

Another challenge was that a normal pickup has a height of about 18mm to 25mm, but this time, the Stealth pickup needs to be able to be neatly stored under the pickguard. When the owner checked the engraved dimensions, we found out that it had to be within a thickness of 10.5mm.

At this point, normal Alnico 5 could no longer be used, but after thinking about what dimensions to use for the neodymium magnet, we decided on a diameter of 3 mm and a height of 10 mm, and by specially designing a base plate and bobbin shape to match, we were able to keep the thickness to 10.3 mm.

Also, since the owner requested noise reduction, we designed it as a JM-sized humbucker rather than a normal single coil like the JM.

The layout diagram looks something like this.

Task 3: How to decide production specifications

Although the design is complete, there are no production examples, so there is no basis for determining which specifications are optimal. If safety (ensuring sound output) is a priority, a high-power specification would be the best, but this may not be in line with the owner's wishes.

Therefore, we proposed the following specifications, on the premise that if any defects arise after installation, they will be repaired free of charge, and if the product differs from what was expected, they will be remanufactured at a special price.

Vintage spec sub coil, slightly modern main coil, medium output

Since this was made with humbuckers, I aimed for a medium output of about 10k in total, and increased the coil tap options by using mismatched coils.

The exact playability will be known only after the actual unit is installed, but the fact that it can produce sufficient volume at medium output means that it will also be possible to play it with a coil tap.

In this case, rather than lining up coil taps with the same specifications, the sub-coil is designed with low output for a vintage feel and the main coil with high output for a slightly more modern feel.If the output is sufficient when using the main coil with a tap, then it is possible to wire it so that the sub-coil is used with a tap according to preference.

As the manufacturer, we have designed it to the extent possible so that it can be set up to suit the owner's preferences.

The main coil is made of thin wire, AWG44, with green enamel.

The sub coil is made from the familiar heavy foam bar.

Completed! STEALTH PU JM size humbucker with neodymium magnet

After much trial and error, it is finally complete! The potting process was also selected based on noise resistance and the owner's sound image, and all pole pieces were also earthed just to be safe.

When we did a trial sound test, we got a sound close to a normal clean tone when we held it at a distance, but it seemed a little hard. We don't know what it will be like when it is installed in the actual machine, but as the manufacturer, we hope that it will be useful and have delivered it to you.

Just a little bit of trivia, but when you test it at the same distance as a normal pickup, it produces a very metallic, sitar-like tone. This tone is probably due to the magnetic force being so strong that it tries to stop the strings from vibrating.

Summary of production specifications

Product name

Custom made pickup production

JM size humbucker STEALTH pickup

Reference price Starting at 16,000 yen + tax per piece (including shipping and design fees)

Neodymium magnet 3mm pole piece 8 rows 2 stages

Vulcanized Fiber Plate

Domestically produced 4-core lead wire

Neck position 10k

Main coil 6k AWG44 green enamel

Sub coil 4k AWG42 heavy form bar

Bridge position 11k

Main coil 6.5k AWG44 green enamel

Sub coil 4.5k AWG42 heavy form bar

accessories Storage packaging, installation sample PG (bonus), free repair guarantee in case of malfunction, remanufacturing discount guarantee, specification sheet
Estimated Delivery Time 2 weeks to 1 month

Thank you very much for your request. If you have any inquiries regarding pick-up orders, please feel free to contact us using the inquiry form.

Nekodamari Kobo Co., Ltd.

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