The Oktava ML15 is a bi-directional ribbon microphone. This particular example was manufactured by the Oktava plant in Tula in 1960.
The Oktava plant was most well-known for manufacturing dynamic microphones, and their ribbon dynamics were of particularly high quality with the ML15 being one of the finest microphones they produced. There is another version of the ML15 manufactured for/by the MRTP (Ministry of the USSR Radio Engineering Industry) that uses a larger output transformer, a crinkle-coat paint job, and a perforated grill which I'll post about another time.
While I cannot confirm this as fact, I can say from experience that the ML15 sounds very similar to the RCA 44BX - their tone is so similar that when side-by-side you might think you were just listening to two different 44's. This mic works beautifully in every application you might expect - room mics for a drum set, vocals, guitar amp, horns, and piano have all been captured beautifully by this microphone in our studio.
