
The JJ which stands for "Jeffrey Jumbo" has become an iconic shape in the world of handmade guitars, admired for its distinctive silhouette, innovative details, and unmistakable character. For many years, original JJ instruments remained rare, with many finding their way into the hands of collectors. With the Core Series, what was once available primarily through one-of-a-kind boutique instruments can now be experienced in an instrument designed to be within reach of a much larger community of musicians. Tonally, the JJ is defined by a full, resonant low end, sparkling highs, and a subtly scooped midrange, creating a wide, open voice with remarkable presence and character.
JJ Core




featuring our signature tonewoods
The Core Series introduces two signature tonewoods that define our approach to modern instrument building:
Monkeypod, pioneered in guitar building by our master luthier Jeffrey Yong, brings a distinctive tonal character and visual identity to the series. Monkeypod possesses a naturally warm and resonant voice, characterized by a strong fundamental, rounded low end, and a clear, articulate upper register. Its open grain contributes to an expressive, full-bodied character, while its natural tonal complexity adds depth and dimension to the instrument’s overall voice.
Monkeypod has previously only been found in highly-crafted, handmade instruments, boutique guitars built in very limited numbers and at a premium.
With the Core Series, what was once available primarily through one-of-a-kind boutique instruments can now be experienced in an instrument designed to be within reach of a much larger community of musicians.
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Alongside it is Tibetan Spruce, a rare high-altitude spruce known for its remarkable growth environment and distinctive acoustic properties. Sourced from high elevations, its slow growth produces a unique character that makes it particularly compelling to us as a soundboard material. Tibetan Spruce provides a clear, dynamic foundation, with a responsive attack and the headroom to translate subtle changes in touch and playing intensity while Monkeypod adds warmth, resonance, and depth, giving the instrument a fuller and more rounded character.
Technical Specifications
Body Shape
JJ
Series
Core Series
Top
Tibetan Spruce
Back & Sides
Monkeypod
Bindings
Rosewood
Finish
High-gloss
Neck Material
Mahogany
Tuners
Muyun Custom
 Radius
15"
Scale Length
648mm
Bridge Pins
Brass
Fingerboard
Ebony
Bridge Material
Ebony
Number of Frets
21

