Book excerpt: (Book). If you have questions about guitar amplifiers-how to fix them, how to restore them, or how to hot-rod them-this book has the answer. This book is written for the guitarist or collector who desires a common sense approach to understanding the essence of vintage tube amps and vintage tube tone. Not written for engineers, it does not contain engineering formulas, polar mathematic equations, or abbreviations that are assumed you should know. Gerald Weber, a regular columnist for Vintage Guitar magazine, shares the knowledge he has accumulated over the years of repairing and building his line of Kendrick amps.