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.

God Forbid

Building up a following in the late 1990s by touring with bands such as GWAR, Nile, Cradle of Filth and Candiria, God Forbid's first full album Reject the Sickness was released by 9 Volt Records in 1999. This album received heavy rotation from WSOU-FM in the New York City area and the band was subsequently signed to Century Media Records, releasing the album Determination in 2001. They played on the MTV2 Headbangers Ball tour with Shadows Fall and Lamb of God. In 2004, they released Gone Forever, which along with a slot on Ozzfest's second-stage, increased their profile considerably. The next year, they released IV: Constitution of Treason, a concept album about the end of the world. It was their first album to enter the Billboard 200, debuting at number 118. In 2005 and 2006, they supported Trivium on their UK tour along with Mendeed and Bloodsimple. In late 2006 and early 2007, they headlined the Chains of Humanity tour.In 2006, God Forbid's "To the Fallen Hero" won the Independent M...

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