A Class T amplifier[1] is the closest you can get to a tube. One of the amplifiers, the TA2020 (1998), was named one of the twenty-five chips that 'shook the world" by the IEEE Spectrum magazine.[2]

[1] http://en.wikipedia.org/wiki/Class_T_amplifier

[2] http://spectrum.ieee.org/semiconductors/processors/25-microc...