A Desktop Reference of Hip Vintage Guitar Amps is the perfect book for someone learning how to service and modify their existing amplifier.  This book covers all the information about real vintage amplifiers you will need.  This book emphasizes Fender and also has Ampeg schematics (over 100 pages).  Author, Gerald Webber is also owner of Kendrick Amplifiers, makes of some of the finest Fender reproductions with their own touch.  This book is worth every penny.