Just ask any guitar player. Tubes, while a hassle and expensive as all get out, Nothing else gives you that mellow sound. They tend to enhance the even harmonic overtones, whereas solid state circuits accent the odd ones. The odd harmonics sound shrill and cold comparitively.
Deram, you are certainly correct in your statement that we cannot do such things. But I will add the word YET. Our present level of technology is not yet advanced enough. But any one or thing that could travel here from another planet, no matter where that planet may be, could indeed possess such a level of technology to permit such things. I feel, IMHO, that we are the aliens we have always sought to find, and simply never knew it.