Riverstone Audio - Tested/Matched Pair (2 Tubes) 7-Pin JAN 5654W Fully-Tested Vacuum Tubes - Upgrade for 6AK5 / 6J1 / 6J1P / EF95 - JAN 5654W Platinum Grade Pair

Riverstone Audio specializes in the testing of vintage US and Russian vacuum tubes used for audio applications. During the past decade, Riverstone Audio has tested over 70,000 vintage vacuum tubes. The proper evaluation of vintage tubes for audio applications requires considerable effort and specialized test equipment. Our workshop has the best available equipment for testing and evaluating the electrical and audio qualities of vacuum tubes, including several state-of-the-art Amplitrex AT1000 tube testers and various vintage and custom-built tube and audio test equipment. The Amplitrex tube testers allow us to determine a vacuum tubes electrical parameters with precision, including plate current, mutual conductance, grid characteristics, gas, life, inter-element leakage and noise. Additional test equipment allow us to evaluate vacuum tubes under different test parameters, including self-bias (cathode bias) test modes. Riverstone Audio personnel are trained professionals, with a detailed understanding of vacuum tube technology and amplifiers. We have the hands-on experience needed to select vintage vacuum tubes that will provide the best possible audio listening experience. Our senior engineers are experienced in running engineering research labs and closely monitor all aspects of testing, matching, and QC procedures and are also available to answer customer questions when they arise.