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.

Matias Cugat / Timmy O'Tool/ Sr. Flavio

ldquo The best equipment I've ever played with or heard used Groove tubes valves. Using them gives me the certainty of quality and sound that I'm looking for and need for my shows and rehearsals" - Matias C. Mat as Cugat, better known as Mono Tot. musician, guitarist, producer and Audio Engineer. Singer and guitarist from TIMMY O'TOOL band, as well as guitarist for SR.FLAVIO's solo project (LOS FABULOSOS CADILLACS ). Since 2000 , with his band TIMMY O'TOOL he has been performing all around America, playing in Chile, Uruguay, Paraguay, Colombia, Mexico, USA and Argentina. With many albums and 5 music videos, the group is well known in America by its explosive and unique live shows. As a producer and recording Engineer, Matias has worked in over 100 albums in the last 10 years with his own production company NO RULES REC. Matias has been working not only like a Room Engineer for the South American Rocker Scene, but also with international artists during their visits to Argentina, such as...

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