Vintage 6P1P-EV (6П1П-ЕВ) tubes from manufacturer SVETLANA, St. Petersburg (RU). A quality long life soviet output tetrodes with improved mechanical strength. Not less than 5000 operating hours when running under prescribed conditions. It is direct replacement of the chinese 6P1 tubes. Tested and measured with the L3-3 tube tester, matched in quads. These tubes are appearing in many amps which are nowadays produced in China. For example: Nobsound MS-10D MKII, Nobsound MS-10D MKIII, Cayin MT-12N, Nobsound 6P1 and many others. 6P1P-EV does not have any direct european or american replacement. It is very close to the EL90/6AQ5, but it has a different pinout (9-pin vs. 7-pin). Year of production: 1985. New old stock, directly from the factory packing.