http://www.freewebs.com/valvewizard/index.htmlThere are several good sites and books. Build your understanding before you play with high voltage. They can be lethal with no second chance.
viewtopic.php?f=2&t=1834 Some stuff there.
Pedals other than being low voltage can be harder to build just because of complexity and small pcb's high parts count.. You get good pratice soldering to a pcb, but not to turrets or eyelets.
An amplifier build on its own is not dangerous. Dannger comes when you apply power. Even unplugged after being energized, there may be some unpleasant surprises in that chassis.
Thats why you learn to work with one hand and eliminate any second point of contact.
If you have ever got a painful static shock when touching a grounded item(doorknob, car handle ),you have experienced a high voltage shock. The difference is the supply behind each. It only takes about 100ma through the heart to kill by causing the heart to go into defibrillation. Without outside aid, you are dead at that point. Thats why you learn to work with one hand and eliminate any second point of contact
Pester your Grandfather for all the help an EE can give.
Read the manual back to front, go through the layout, learn how to read the schematic.
Do the build and get help with the power up. And having a concerned EE in the back pocket is a nice resource to have.