Matched pair of vintage 6F6M1 (6Ф6М1) tubes from manufacturer Nevz, Novosibirsk (RU). Tubes were tested and measured with professional analogue tester L3-3. We have picked the tubes with the closest characreristics (please look at the samples in the gallery). The 6F6M1 (6Ф6М1) pentode was designed for output stages of low frequency amplifiers. These are the metal base older versions of the 6F6M1 tubes (nominal plate current is around 34 mA and nominal transconductance is 2,5 mA/V). It directly replaces the 6F6S (6Ф6C), 6F6M (6Ф6М) and also the 6F6 and 6F6G pentodes, it has only a different shape as you have probably already noticed (all other important electrical characteristics are basically the same and all these tubes are interchangeable without any additional electrical adjustements). All of the available tubes are new in box, each box has also a label with actual measured parameters attached (plate current and transconductance). Year of production:1953.