The Groove Tubes GT-12AT7 preamp tube is manufactured to the highest quality JAN spec. NOS, made in Russia for extremely long life. Used widely in most U.S.-made amps and, in particular, Fender amps. ... Read More
The Groove Tubes GT-12AT7 preamp tube is manufactured to the highest quality JAN spec. NOS, made in Russia for extremely long life. Used widely in most U.S.-made amps and, in particular, Fender amps. Fender amps with reverb use 2 - 12AT7s -- one for the reverb drive stage, and one as a phase inverter to drive the push/pull output stage. The makeup of the 12AT7 is very similar to the 12AX7 and it can be substituted for a 12AX7 in a pinch. Some players prefer the 12AT7 in the driver stage of a Marshall for a cleaner, brighter tone. (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 Groove Tubes GT-12AT7 is selected for durability.
Country of origin: Russia
Reviewed by 2 customers
Displaying reviews 1-2
It seems like the previous reviewer did not understand the use of the AT7 tube. It is used in the reverb channel or more importantly in the phase inverter position (the tube before the first power tube). The GT website even states this. It is primarily a functional tube (above) and not a tone tube to be used in V1 of V2. It is roughly 80% the power of an AX7. This tube does contribute more to feel than tone and is brighter and more pick sensitive when used as a PI. You can increase the Master volume and use it to overdrive the power tubes. I'm not a fan of GT but this is one of their best tested Russian tubes (still used as military standard) and durable tubes made to last. So use it correctly and you will get a softer, more articulated playing amp!
I was persuaded into buying these tubes instead of waiting for the JJ tubes I should've waited for. They sound so overly-mellow and flat with no punch. They are not bright like the salesman told me, and you can barely hear the high end in chords. Playing the higher strings is the worst, as they sound bare and empty. Not to mention that everywhere you read about Groove Tubes, it says they're just re-packaged and re-labeled (sometimes cheaper) tubes from other brands. Save yourself the stress and money... don't buy these.
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