Groove Tube Matched 6L6R Medium Duet Power Tube Our Groove Tubes GT6L6RDM power output tubes are Russian made, and a very robust and dependable vacuum tube design. These tubes are interchangeable with Russian made 5881s, but offer better performance when used in matched sets. They are slightly less powerful than some 6L6s, but have a more aggressive edge when pushed to distortion. These tubes are so reliable that Fender uses them in their Hot Rod, Blues DeVille, Pro Tube, and BF Reissue series tube amplifiers. The red markings on the exterior of the tube is Fender's color code, corresponding to an 8-10 on the Groove Tube rating scale (which means they are in the top category). Tubes don’t last forever; they actually wear out with use, and the harder you work them the faster they wear out. When one tube starts to go, it drags the others down with it, decreasing the overall efficiency of the amplifier. In the case of your power stage tubes, most amplifiers use a push/pull, alternating design with an equal number of tubes on each phase. When one tube is off, the other is on; and vice versa. If one tube is weaker, then the stronger tube will have to harder to make up for the weaker tube, and your amp’s performance will be off, and getting progressively worse. Our Groove Tubes GT 6L6RDMs come in matched sets. Matched tube sets dramatically improve sustain by eliminating phase cancellation ,which occurs when dissimilar tones coming from unmatched tubes are combined and cancel out certain frequencies. You will also have improved harmonic balance, meaning all the notes you play will have the same amplitude. No weak or dull spots in your tone. You will also have longer life from your amp, since balanced tube sets reduce stress that occurs when a stronger tube has to work harder to make up for a weaker partner. Your output transformer will actually run cooler, because matched tube sets drive the output transformer evenly. Tubes are a lot like strings, in that they loose their tone and performance when they start to deteriorate. You should change your tubes before they totally burn out, to keep your amp at its peak performance and your tone at its sharpest. After all, you don’t wait for your stings to break before you replace them. Eventually, you will have to replace your tubes. and the best reason to replace them with Groove Tubes is that they will make your amp sound better and last longer. It's also a good idea to plan ahead for the day when you'll need new tubes to save the gig. Get a set of Groove Tubes before you actually need them. Even if you put them in early, you'll feel you're doing the right thing, and you'll like the results and peace of mind. Note: One "duet" of matched tube contains 2 tubes. You get a matched duet, not individual tubes.
