Try the following page:www.bonavolta.ch/hobby/en/audio/sv811_2.htmI built mine as a stereo amp with outboard power supply and a 6DN7 input/driver, which I liked a little better. Most recently added inexpensive grid chokes. Sweet amp. I was hoping you would change your mind as I am looking for cheap spares for the output and didn't want you to popularize it : )