it is called TRPA.
All amplifiers composed of semiconductor in no use of vacuum tube. 'Recent TRPA is FET.

The vacuum tube is being used in various places in the world of the broadcasting technology to show high power now.

it did about the amplifier of making to the solid etc.
to distinguish from the amplifier that was able to be done with the vacuum tube ..saying.., and most amplifiers (audio amplifier) that used the present transistor were vacuum tubes in all old times why. Still, the audio amplifier of the vacuum tube is extolled among the manias.

Will it be a fluid? Might say the solid with what however and the vacuum tube are mysterious.

The large vacuum tube with the thing that consists of the can of the metal, too is a bucket though the vacuum tube has the image of the glass.