Gotoh SD90 Magnum Lock '3-a-Side' Tuning Keys – Gold

The Gotoh SD90 Magnum Lock series offers the perfect fusion of classic vintage aesthetics and modern mechanical precision. Designed for players who want to maintain the traditional "Keystone" look of their instrument while benefiting from the superior tuning stability of a locking system, these tuners are a premium upgrade for any 3-a-side headstock. Finished in a stunning Gold, they provide a high-end touch to both vintage restorations and modern builds.

Discreet Magnum Lock Technology

Unlike bulky top-locking tuners, Gotoh’s Magnum Lock functionality is discreetly integrated into the string post. As you wind the string, the mechanism automatically locks the string in place, eliminating the need for multiple wraps around the post. This significantly reduces string slippage and improves tuning stability, especially during aggressive bends or heavy tremolo use. With a 15:1 gear ratio, these tuners allow for smooth, precise adjustments every time.

Installation & Compatibility Note

These tuners are built to Vintage Specifications, requiring an 8.8mm (11/32") headstock hole. Because these units utilize designated string hole sizes calibrated for specific strings, they are designed strictly for Right-Handed use. If your guitar currently has larger modern holes (9.5mm - 10.5mm), adaptor bushings will be required for a correct fit.

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Key Performance Features

  • Vintage Keystone Buttons: Classic look ideal for Gibson® style and other traditional acoustic and electric guitars.
  • Magnum Lock System: Automatic locking as you tune for faster string changes and rock-solid stability.
  • 15:1 Tuning Ratio: Balanced precision for accurate fine-tuning.
  • Complete Hardware Kit: Includes press-fit bushings and color-matched fixing screws.
  • Premium Gold Finish: High-quality plating for long-lasting corrosion resistance and visual appeal.

Detailed Specifications

Configuration 3-a-Side (3 left, 3 right)
Locking Mechanism Gotoh Magnum Lock
Gear Ratio 15:1
Post Diameter 6mm
Required Hole Size 8.8mm (11/32")
Finish / Button Gold / Vintage Keystone

Frequently Asked Questions

Will these fit my modern Gibson or Epiphone?
Most modern guitars use 10mm "die-cast" holes. Since these are vintage-spec (8.8mm), you will likely need "Conversion Bushings" to bridge the gap between the 6mm post and the 10mm hole. Always measure your headstock holes before purchasing.

Why are these for Right Hand use only?
The Magnum Lock system uses graduated string hole sizes. The holes for the low strings are larger than the holes for the high strings. Inverting them for a left-handed headstock would result in the low strings not fitting through the posts.

How do I unlock the strings?
Simply detune the string. Once the tension is released, the internal mechanism will disengage, allowing the string to be pulled out easily.

SKU SD90MG-002
Brand Gotoh
Shipping Weight 0.2900kg
Shipping Width 0.070m
Shipping Height 0.050m
Shipping Length 0.160m
Shipping Cubic 0.000560000m3
Unit Of Measure ea

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