National Horizon 20 HiFi Amplifier Manual Sorry, this product cannot be purchased. $8.99 Category: National Description Description For sale is reprint of National Horizon 20 HiFi Amplifier Manual. Manual is 8 pages Includes Part List and Circuit Diagram. Manual also includes 2 Service Bulletins Hi-Fi-8 and Hi-Fi-9 Related products National NC-173 NC173 Radio Receiver Manual $10.49 Read more National NC-183 NC183 Radio Receiver Manual $11.99 Read more National NCL-2000 NCL 2000 Linear Amplifier Manual $10.49 Read more National NC-57 NC57 Radio Receiver Manual $10.49 Read more