在音頻放大器應用領域，DSP （數字信號處理）技術日臻完善， 已經可以 完全取代真空管電路。 內容詳見下麵鏈接：
http://www.mitpressjournals.org/doi/pdf/10.1162/comj.2009.33.2.85
附一個博士論文：
http://cegt201.bradley.edu/projects/proj2003/dtubeamp/
By: James Siegle
Advisor: Dr. Thomas L. Stewart
Abstract
Solid-state technology may dominate the present electronics world, but vacuum tubes continue to hold influence in the guitar amplifier industry. The sound of a guitar playing through a vintage vacuum tube amplifier has become a standard for most guitarists. Unlike solid-state guitar amplifiers, vacuum tube amplifiers produce specific, disorted guitar sounds. The quality and amount of harmonic distortion in overdriven vacuum tube guitar amplifiers has been found to be pleasing to several musicians. This desirable effect has been termed "tube distortion." Even though vacuum tube designs for guitar amplifiers are characterized by their superior sound, their disadvantages include high cost, fragility, limited availability of components, high waste heat generation, and manufacturing inconsistencies in the tubes. The objective of this project is to reproduce the distinct harmonic distortion of a 1961 Fender Champ with a low-cost DSP and thus implement a guitar amplifier with tube distortion without the bulky and awkward features of a tube amplifier. Once the DSP-based design is completed for this small amplifier, the algorithm can be reconfigured for other vintage vacuum tube amplifiers.
