SW1X Audio Design™ MPA IV “Aurora” Performance Level 3/4/5 2A3 DHT Valve Mono Power Amplifier   MPA IV is a Pure Class A, Zero Negative Feedback, Directly Heated Triode, Fully Valve Rectified, Single Ended, 3 Gain Stage, Interstage Transformer coupled, Mono Power Amplifier. The 2A3 Triodes in combination with 6V6 triode connected driver tubes provide … Continue reading SW1X MPA IV “Aurora” Mono Power Amplifier