| Form Factor | Part |
| Signal Path | Analog Hardware |
| Dimensions | 3.8 × 12.1 × 25.4 cm (W × H × D) |
| Weight | 3lbs |
| Power | 6.3VAC 0.6A, 260VDC 10mA |
| Frequency Response | 20Hz-20kHz ±1dB |
| Gain | 40dB |
| Gain (Special Connections) | 34dB |
| Source Impedance | 30/50Ω, 125/150Ω, 250/300Ω 500/600Ω |
| Load Impedance | 3050Ω, 125/150Ω, 250/300Ω, 500/600Ω |
| Output Level | +20dBm |
| THD (50Hz-15kHz) | 0.5% |
| THD (30Hz-15kHz) | 1% |
| Equivalent Input Noise | -120dBm |
| Output Noise | -80dBm |
| Tube Complement | 12AY7 (x2) |
| Links | Altec 250A Console |
| Notes | A-428B with minor revisions and changed model number to fit with revised nomenclature structure.
250A Console plug-in module. Available separately for custom installations. |
