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.

David Flinn / Chelsea Grin

A "Chelsea Grin" in soccer hooligan terminology is the act of cutting a rivals mouth with either a credit card or blade and then kicking them in the crotch so their mouth muscles split into a bloody grimace. Chelsea Grin, the band from Utah armed with THREE guitarists, use a foundation of hardcore grit combined with death metal technicality and speed to produce as much aural harm as the back alley jaw split. The band is the premiere artist on Artery Recordings, a new imprint of Razor Tie Entertainment, and have released two full length albums. My Damnation is the newest release from Chelsea Grin and is pushing the band to be the next household name in metal.

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