SW1X Audio Design™ MPA III “Oracle” Performance Level 3/4/5 45 DHT Mono Power Amplifier   MPA III 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 Directly Heated 45 Triodes at the output are well known for their … Continue reading SW1X MPA III “Oracle” Mono Power Amplifier