Some time ago, a friend gave me his tube amplifier to test and compare against my solid-state amplifier. At the beginning, I was skeptical. However, I was immediately struck by the purity and clarity of the music it fed to my speakers. The more I used it, the more I realized that technology used fifty years ago was competing and even beating more recent technology.
I was even more surprised when my friend told me that his amplifier was a “Do It Yourself” project. I was impressed by the fact that it was possible to build at home an audio amplifier offering a comparable, or even better, audio quality than a branded, and supposedly good quality, amplifier.
Well, I took the challenge. For sure, on the internet I should have found plenty of good schemas and projects. I just needed to choose the best one to build my own first vacuum tube amplifier. I started searching and after a few clicks I collected a good number of options. It was very easy. At that point, I just needed to choose the best one. Here the problems started. Looking at the reviews of the various projects, both from supposed technical experts and audiophiles, I found conflicting opinions. The same project and solution was at the same time exceptional according to some and nonsense according to others.
In order to be able to discriminate I needed to learn about vacuum tube amplifier design and develop the needed skills to be able to judge. So, I started studying, simulating, prototyping, and measuring. Eventually, I was not only able to read and interpret projects. I was also able to design and build my first integrated push-pull vacuum tube amplifier.
Writing this book was motivated by the need to synthetize, in a simple and consistent form, all pieces of information that I collected. At the beginning, it was just for my own use. I wanted to avoid searching for information from scratch and draw conclusions I already figured out months before. I needed to preserve the information and knowledge I acquired for future use.
After a while I realized that this, with a small additional effort, could become a book for the general public, … well, … hopefully, … at least for the possibly interested public. This is how this book was born.