Analog amplification vacuum tube

An analog amplification vacuum tube comprising:

• a filament tensioned linearly and emitting thermalelectrons;
• and
• two sets of a grid and an anode, wherein
• both of the anodes are formed on a same surface on a planar substrate,
• the filament is disposed parallel to the planar substrate at a position facing both of the anodes,
• each of the grids is disposed between the anode and the filament so as to face a same set of the anodes at a first predetermined distance and so as to have a second predetermined distance from the filament,
• the analog amplification vacuum tube comprises:
• an intermediate filament fixing part that fixes the filament at a position corresponding to an intermediate point between the anodes of the two sets;
• and
• two vibration-proof parts comprising a thin film usable in a vacuum environment,
• the thin film of one of the vibration-proof parts is in contact with the filament between the intermediate filament fixing part and a part facing one of the anodes, and
• the thin film of another of the vibration-proof parts is in contact with the filament between the intermediate filament fixing part and a part facing another of the anodes.