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 NTX-30 Radio Transmitter Manual $9.99 Read more National NCL-2000 NCL 2000 Linear Amplifier Manual $10.49 Read more National NC-44 NC44 Radio Receiver Manual $5.99 Read more National NCX-3 NCX3 HAM Transceiver Manual $9.99 Read more