A-402 subwoofer amplifier with complete crossover and room equalization

Improvements comparing to the A-401:
1. The 6 large capacitors are of higher value
2. The volume control is more precise
3. The bandwidth of the BASS BOOST and EQUALIZER LEVEL is narrower
4. Chassis and component grounding is now more immune to hum and noise
5. The speaker terminals will now accomodate to 16 mm cables
6. Transformer vibrations are very low