AA-91
| Brand | Heathkit |
| Manufacturer | Heath Company, Daystrom, Incorporated |
| Function | Amplifier, Power (Kit) |
| Produced | 1960 |
| Country | United States |
| Signal Path | Analog Hardware |
| Dimensions | 38.1 × 15.5 × 20.3 cm (W × H × D) |
| Weight | 26lbs (Shipped) |
| Power | 117VAC, 50/60Hz, 90W 160W (Max) |
| Frequency Response | 20Hz-20kHz ±1dB |
| Output Power | 55W |
| IHFM Music Power Output (0.7% THD, 1kHz) | 67W |
| Impedance Load | 4/8/16Ω/70.7V |
| Input Sensitivity | 2V |
| THD (20Hz-20kHz, 55W) | 2% |
| IMD (4:1, 60Hz:6kHz, 62W) | 1% |
| SNR | 80dB |
| Damping Factor | Unity or 20 (User Selectable) |
| Output Tube | EL34 |
| Tube Complement | EL34 (x2), 6AN8 |
| MSRP (1961) | $59.95 |
| Channels | 1 Channel |
| Links | Predecessor: W-7A |
| Notes | Updated W-7A |