У вашего броузера проблема в совместимости с HTML5
Testing a 12AX7 Dual-Triode on a B&K 650 with 610 Panel as well as a B&K 707 and a Hickok 600A Tube Tester. Analysis uncludes the bias level and settings that overcome the test anomaly mntioned in a previous video on Testing Newer Tubes with a B&K 650