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.



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



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



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


Knoxville, Tenn., deathcore sextet Whitechapel is named for the infamous section of London where the Jack the Ripper murders were committed. The band formed in 2006 and currently consists of vocalist Phil Bozeman guitarists Ben Savage, Zach Householder and Alex Wade bassist Gabe Crisp and drummer Kevin Lane. Whitechapel recorded demos almost immediately after forming debut discThe Somatic Defilement was released in June 2007. The group signed that fall to Metal Blade Records. Second album This is Exile appeared in 2008 and reached number 118 on the Billboard Top 200 chart. The band toured extensively in 2008, including its first-ever headlining tour, and appeared on the summer 2009 Rockstar Energy Mayhem Festival.

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