W-4M
| Brand | Heathkit |
| Manufacturer | Heath Company |
| Function | Amplifier, Power (Kit) |
| Produced | 1954 |
| Country | United States |
| Model ID | Williamson Type Amplifier W-4 |
| Signal Path | Analog Hardware |
| Dimensions | 38.7 × 17.8 × 22.4 cm (W × H × D) |
| Weight | 28lbs |
| Power | 105-125VAC, 50/60Hz 120W |
| Frequency Response | 10Hz-100kHz ±1dB |
| Output Power | 20W |
| THD (20Hz-20kHz, 5W) | 0.5% |
| IMD (60Hz:3kHz, 5W) | 0.5% |
| Impedance Load | 4/8/16Ω |
| Output Tube | 5881 |
| Tube Complement | 6SN7GT (x2), 5881 (x2), 5V4G |
| Output Transformer | Chicago Transformer Company BO-13 |
| MSRP (1954) | $39.75 |
| Channels | 1 Channel |