R-390A Tube Complement
| Ref. | Tube | Function |
| V201 | 6DC6 | RF amplifier |
| V205 | 5814A | Calibrator oscillator, 100 KHz cathode follower |
| V206 | 5814A | 100KHz multivibrator |
| V202 | 6C4 | First mixer |
| V207 | 6AK5W | First crystal oscillator |
| V203 | 6C4 | Second mixer |
| V401 | 6AK5W | Second crystal oscillator |
| V204 | 6C4 | Third mixer |
| V701 | 6BA6W | VFO |
| V501 | 6BA6W | First IF amplifier |
| V502 | 6BA6W | Second IF amplifier |
| V503 | 6BA6W | Third IF amplifier |
| V504 | 6AK6 | Fourth IF amplifier |
| V506 | 5814A | Detector, AGC time |
| V509 | 5814A | IF cathode follower, AGC rectifier |
| V508 | 6BA6W | AGC amplifier |
| V505 | 6BA6W | BFO |
| V507 | 5814A | Limiter |
| V601 | 5814A | First AF amplifier, cathode follower |
| V602 | 5814A | Second AF amplifier (line and local) |
| V603 | 6AK6 | AF out local |
| V604 | 6AK6 | AF out line |
| V801 | 26Z5W | Rectifier |
| V802 | 26Z5W | Rectifier |
| V605 | 0A2 | Voltage regulator |
| RT510 | 3TF7 | Current regulator |