Published in 1972 (1977 edition) by Seibundo Shinkosha Stereo Mania Production Handbook Construction articles for a total of 23 amplifiers, including vacuum tube amplifiers (1 transistor amplifier, 1 IC amplifier), and most of them include actual wiring diagrams in addition to circuit diagrams, making them easy to tackle even for amplifier beginners. It's old, so I don't know how available the parts are, but some quite rare parts are being sold on auction sites and elsewhere, so I think you can manage. The book is in poor condition, so the cover has a film cover on it.