Riverstone Audio - Matched Quad (4 Tubes) GE JAN 5654W Fully-Tested Vacuum Tubes 6J1 / 5654 / 6AK5 / EF95 / 6AK5W / 6J1P Tube Replacement - 5654W Platinum Grade Quad Closely Matched Quad (4 PCS) of GE 5654W Vacuum Tubes The 5654W vacuum tubes used in our Platinum Grade Matched Quads are carefully matched at Riverstone Audio. We match these tubes for BOTH plate current and mutual conductance. Each tube box is labeled with test results. For our special Platinum Grade Matched Quads, the 5654W tubes will test above 5200 micro-mho and at a plate current of 7.5 mA or higher. Matching is conducted using a state-of-the art Amplitrex AT1000 vacuum tube tester. All vacuum tubes sold by Riverstone Audio must pass an additional array of quality checks, inlcuding shorts/leakage, gas, noise and a specialized life test. Only the best vintage 1988 tubes are selected for Riverstone's Matched Quads. Premium upgrade for the 6J1, 6AK5 and EF95 Tubes used in Little Bear, Little Dot, HIFIMAN, Yaqin, headphone amps and other quality preamps and amplifiers.