The PRB-5500 is a right-handed set of RATIO® Calibrated Machine Heads for BASS that use a 5-in-line configuration.
In order to achieve higher gear ratios, Ratio are the world's first machine heads using a double envelope gear design with a hardened steel gear. Amazingly smooth and super strong.
Headstock Configuration 5-in-line Ratio Tuned Machine Heads: The New Standard In Tuning Technology
Gear ratio: unique for each string position - one turn-one tone
Peg holes diameter required: 35/64" (14mm)
String post diameter: 0.547" (13.9mm)
String post length to string hole: 1.030” (26.1mm)
Weight per single machine head: 1.86oz (53g)
Weight per set of four: 9.3oz (265g)
String diameter up to 0.98 gauge (or larger if taper-wound)
Includes 5 machine heads, mounting screws, and bushings
RATIO® patented gear technology
RATIO® - Calibrated Machine Heads incorporate different string gauges into the tuning equation.
From Low E to G - 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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About GraphTech
From a kitchen table start up in the early 1980’s Graph Tech Labs has become the undeniable #1, an innovative and unique institution, inventing, patenting, and producing an endless selection of essentials to improve and enhance tone, playability, reliability and versatility for all fretted instruments and players.
Famous for nuts, Graph Tech’s proprietary Tusq, NuBone and NuBone XL top nut and saddle materials offer a limitless choice of options for players to “up their tone”. Technological advances such as Ratio Tuners improve tuning speed and accuracy. Graph Tech’s Ghost Acousti-Phonic modular pickup system lets you “Be the Band”, with a studio quality true acoustic tone and Ghost Hexpander MIDI compatible output and unparalleled tracking, at the flick of a switch.
Explore the world of Graph Tech and discover why over 140 of the worlds top guitar brands fit GraphTech as original equipment, and countless guitar builders, repairers and players have chosen Graph Tech nuts, nut lubricants, saddles, bridges, bridge pins, string trees, picks, machine heads, electronics, pickups, and hand treatments to enhance the performance of their instruments and playing.