| A. G. Tannenbaum's Homepage | Manuals, Test Equipment |
| Audio Oasis.com | Retailer, Tubes |
| Bill's Ham Radio | Tube Database, Manuals |
| Dredge | Schematics, Manuals |
| Electron tubes and-or Vacuum tubes | Tubes, Manuals for old RCA Radios |
| Electronics | Service and Owner Manuals |
| Hickok | Tube Tester Manual |
| Infotronix | Manuals, Schematics |
| ManualMan | Service Manuals |
| Marshall Transformer Codes | Information about Tube Audio - Articles, Schematics, Manuals |
| Mauritron Technical Services | Service and Repair Manuals |
| Nostalgia Air | Vintage Radio References |
| RCA PG5 | Manual |
| StereoManuals.com | Manuals |
| Treasure Chest Corp. | Manuals |
| Vacuum Tubes, Electron Tubes, Tubes, Tube Testers and Electronic Parts | Tubes, Parts, Testers, Manuals |
| Vacuum Tubes, Inc., Electron Tubes | Tubes, Sockets, Manuals, Schematics, Information, Radios |