I decided to do a Dynaco ST-70,as it was my first,got the chassis and transformers on ebay,downloaded the construction manual and schematics, then surfed the web for all of the upgrades.It would have cost over $700 to buy an older stock unit and redo it.I bought used transformers and had around $550 in the whole thing.If you are interested in learning more e-mail me;curtis1@zoomnet.net, my next project will be similiar to the ST-70, but I am going to use SA3's in a triode configuration with a Triode Electronics driver board. After that I am going to tackle the ultimate goal 300B's class A.