For sale is reprint of National NCL-2000 Linear Power Amplifier manual. Manual is 20 pages long, includes 11×17 foldout of Circuit Diagram and 8 pages on RCA-8122 tube.
Manual covers Installation, Operation, Theory and Service Instructions. 2 Page section on troubleshooting, part list and Circuit Diagram. There are 8 pages of information on RCA-8122 tube used in this amplifier (amp uses 2 8122 tubes).