Many folks who buy our tubes know that we use a special process to categorically rate our tubes so that players can select the tubes that best fit their preferred tones and styles. However, we get a lot of questions about our rating system, and what the numbers actually mean.

IMPORTANT BIAS NOTE: If you're replacing a tube with the SAME TYPE of Groove Tube (tube model and rating), you do not have to rebias your amp. In any other case, you should always have a qualified amp tech reset your amp’s bias whenever changing your tube type or rating number.

low

1-3

Early distortion, wide range, softer attack good for Rock and Blues solos.

Medium

4-7

Normal performance, great dynamic range/attack and best all around rating type for all styles of playing

High

8-10

Most dynamic range, most clean power/less break-up for power players, Jazz and bass amps.

Tony Franklin

The names of few bassists over the past two decades have become more synonymous with the fretless bass guitar than that of Tony Franklin - the Fretless Monster! In January 2006, Fender proudly introduced the Tony Franklin Signature Model Fretless Precision Bass guitar, the design of which the renowned bassist played a prominent and hands-on role in (Franklin juggled his professional music career with his numerous artist relations duties for Fender Musical Instruments Corporation and his role as a clinician for Fender and SWR through mid-2011). It's quite a distinctive instrument Franklin used the original in his work with Jimmy Page, Paul Rodgers, Whitesnake, Blue Murder, numerous sessions and his own successful solo career. A born performer who first took the stage at age 5, Franklin got his big break in 1984 as bassist in stellar supergroup the Firm, with guitar legend Page, vocalist Rodgers and drummer Chris Slade (AC DC, Manfred Mann's Earth Band). Franklin's signature fretless gro...

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