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.

The Devil Wears Prada

Forget everything you knew about The Devil Wears Prada. The technically proficient, guitar-driven American metal that you'll hear on the band's fourth studio album, Dead Throne, is bigger and more balanced than what was contended with on 2009's breakthrough offering, With Roots Above and Branches Below, and 2010's Zombie EP. Dead Throne signals a more evolved, more progressive The Devil Wears Prada that is not only larger sonically, but goes much deeper, lyrically. The album contains more than a dozen cutting-edge, razor-sharp, straight-ahead metal tracks that are utterly brilliant not only in their composition, but also in their flawless delivery. "The songs are inspired by a lot of the things in my heart, per usual," explains frontman Mike Hranica. "A lot of the subject matter was very specific for this record, which is something that has evolved for me. I'd call the album very'lyrically intentional.'rdquo Dead Throne was expertly produced by Killswitch Engage mad genius Adam Dutkiew...

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