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.

Bruno Mars

It's better if you don't understand just listen and have a good time. That's the response Bruno Mars will give you with a smile when asked to describe his sound and music. He would much rather sing, perform, and write his songs than talk about them, but that is becoming more and more unavoidable these days. It might seem that Mars appeared out of nowhere, co-writing, producing and performing on B.o.B's 1 "Nothin' On You" followed by Travie McCoy's chart-climbing "Billionaire", but he makes one thing clear: "It's not an overnight success".Mars is a multitalented singer, songwriter, producer and musician who feels most at home when he's performing. Born to a musical family in Honolulu, Hawaii, he was practically raised on the stage. His father, a Latin percussionist from Brooklyn, organized a Vegas-style revue that featured the entire family, including his mother, a talented vocalist. When a four-year-old Mars observed his family performing Motown hits, doo-wop medleys and impersonations...

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