GearNuts Essentials Make Your Axe Rock!Just so you know: the Groove Tubes tubes and sets we sell are all "Mediums." That's in the 4 to 7 range on Groove Tubes' scale. Sorry, we cannot take returns on tubes.
Groove Tubes has been manufacturing, importing, and grading quality power tubes for two decades. No stranger to GearNuts, Groove Tubes founder and energy source Aspen Pittman has paid us numerous informative (and always entertaining) visits through the years. His tireless pursuit of perfect tube tone has resulted in Groove Tubes' reputation for consistency and premium quality. Want proof? Fender tube amps now include Groove Tubes as standard gear, and true tube aficianados worldwide swear by the tubes and pro audio products Groove Tubes makes. For premium tube tone, go with Groove Tubes!
The GT-12AT7 preamplifier tube is used widely in most of the U.S.-made amps (Fender amps, in particular). Fender amps with reverb use two 12AT7s: one for the reverb drive stage, and one used as a phase inverter to drive the push/pull out stage. The 12AT7's makeup is totally similar to the 12AX7 and can be substituted for a 12AX7 in a pinch, although it lacks the 12AX7's character. Some players do prefer to use the 12AT7 in the driver stage in a Marshall for a cleaner, brighter tone (Tip: the driver or phase inverter is the 12AX7 located nearest the power tubes). The 12AT7 is rarely used in a tone-generating stage, but rather in function stages, so the GT-12AT7 is selected for durability. This tube will some times bear the number 6201 plus 12AT7. This is a special (and more expensive) production run with a rugged construction. The GT-12AT7 is tested under extreme listening conditions and guaranteed to be free of excess noise and microphonic ring.