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Graph Tech Guitar Labs

Graph Tech PRB-5320-B0 Ratio 5-String Bass Tuners

RATIO tuners use string-specific gear ratios for smooth, consistent tuning across all strings, making pitch adjustments faster, more accurate, and easier than traditional tuners.

$127.02 $149.44

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Overview
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RATIO Machine Heads: Revolutionizing Guitar Tuning

Every string on a guitar reacts differently to tuning adjustments, and understanding this is key to achieving perfect pitch. The thicker the core of the string, the faster it responds to changes in tension. For example, the pitch change on a plain G string is three times greater than that of the high E string, making tuning the plain G and low E strings—both with thicker cores—particularly challenging. The plain G string is also prone to going out of tune; if stretched, it can catch on the nut or slip on the string post, amplifying tension and pitch changes by a factor of two or three compared to thinner strings.

Traditional tuning methods, such as the "one-ratio-for-all-strings" approach (1:1, 16:1, 18:1), have been in use for over 300 years, relying on worm gear technology that’s over a century old. These outdated methods have left guitarists struggling with inconsistencies in tuning. RATIO Machine Heads address these challenges by assigning a unique gear ratio to each string, ensuring that every string feels and responds uniformly, similar to the easy-to-tune B string.

How did we achieve this?

We meticulously determined the ideal gear ratios for a 360-degree rotation of the tuning knob to produce a full tone change for each string. For electric guitars, the gear ratios range from 39:1 to 12:1 (low to high), and we also offer options for 7-string guitars. For acoustic guitars, the ratios range from 39:1 to 12:1 (including a wound G string). Bass players can enjoy our ratios of 48:1, 36:1, 25:1, and 23:1, available for 4, 5, and 6-string configurations.

Why upgrade to RATIO Guitar Machine Heads?

You gain precise and predictable tuning control over every string, making re-tuning, open tunings, and minor adjustments 100% faster. It's akin to driving a car with an automatic transmission—fast, smooth, and relaxed.

Transform your playing experience with RATIO Machine Heads today!

Graph Tech PRB-5320-B0 Ratio 5-String Bass Tuners Features:

ATIO - Calibrated Machine Heads incorporate different string gauges into the tuning equation.
From Low B to G - 48:1, 36:1, 30:1, 20:1, 18:1.
We balanced the gear ratios to each string simplifying the tuning process.
With RATIO, a half-turn is a semi-tone!
Every string reacts the same to any tuning adjustment. Predictable, precise tuning, on every string.

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Graph Tech Guitar Labs

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Graph Tech PRB-5320-B0 Ratio 5-String Bass Tuners Specifications

Graph Tech PRB-5320-B0 Ratio 5-String Bass Tuners Specifications
Product Specifications	Intended Instrument: Bass Configuration: 3+2 Finish: Black Gear Ratio: 48:1, 36:1, 30:1, 20:1, 18:1 Peg Diameter: 0.350" (peg), 0.547" (13.9 mm peg hole)