Pernyataan menarik kenapa tabung vakum suaranya lebih ‘bagus’ dibandingkan transistor bipolar. Op-amp modern banyak yang menggunakan JFET dan MOSFET. Konon suaranya lebih bagus.
“Many audio experts believe that the sound quality of a high performance FET op amp is superior to that of bipolar op amps. A possible reason for this is that bipolar designs generate greater od-order harmonics than FETs. To the human ear, odd-order harmonics have long been identified as sounding more unpleasant than even-order harmonics. FETs, like vacuum tubes, have a square-law I-V transfer function which is more linear than the exponential transfer function of a bipolar transistor. As a direct result of this square-law characteristic, FETs produce predominantly even-or- der harmonics.”