Tube microphones

 

— such models work on the same principle as “ordinary” condenser microphones: the membrane plays the role of one of the capacitor plates, and when it oscillates, the capacitance of the capacitor also changes. The key difference is that the amplifying circuit of the microphone is assembled on the basis of tubes, not transistors. By itself, the capacitor principle provides high quality sound transmission at all frequencies, and due to the operation of the amplifying circuit at the microphone output, the same “warm tube sound”, appreciated by many audiophiles, is obtained. This is cheaper than using tube amplifiers, although the microphones still turn out to be expensive — much more expensive than standard condenser ones.