A-420
| Brand | Altec, Altec Lansing |
| Manufacturer | Altec Lansing Corporation |
| Function | Amplifier, Pre |
| Produced | 1946 |
| Country | United States |
| Form Factor | 19" Rackmount |
| Signal Path | Analog Hardware |
| Dimensions | 48.3 × 8.9 × 17.8 cm (W × H × D) |
| Weight | 12lbs |
| Power | 6.3VAC 0.5A, 325VDC 6mA |
| Frequency Response | 20Hz-20kHz ±1dB |
| Gain | 42dB |
| Gain (High) | 49dB |
| Power Output (0.001W) | -2dBm |
| Noise Level (0.001W) | -77dB |
| Input Impedance | 30/50Ω, 250/300Ω, 500/600Ω |
| Load Impedance | 62.5/75Ω, 125/150Ω, 250/300Ω, 500/600Ω |
| Tube Complement | 6J7 (x2) |
| MSRP (1947) | $142 |
| Channels | 1 Channel |
| Notes | Designed for operation with Altec A-127-A, A-127-B or A-256-A amplifiers |