Here's a cool proejct by Canadian JCayer, who has blogged the step by step rebuilding of a Riviera 725 tube amp head.
It's a good guide for anyone who wants to attempt this kind of thing.
Le blog de JCayer
I cleaned up my tab for Sonny Boy's Help Me and made it into a short book. There's a Kindle version for 99 cents, and if you buy the paperback you get the Kindle free.
Playing "Help-Me" In the Style of Sonny Boy Williamson II: A step by step, note for note analysis of some of Sonny Boy's Signature Riffs