Single-ended Class A amplifier

Power amplifier single ended class A Orpheus

 This amplifier is designed with zero negative feedback (ZeroNFB),  pure Class-A and definitely single-ended. The amplifier is built around the BUZ-900 N-Channel MOSFET

We use Mundorf Mcap SUPREME SILVER / GOLD or AMPOHM WOUND PRODUCTS – FP-CA-10-AU capacitors

for the input coupling and a large electrolytic on the output with a 10 µF polyester bypass capacitor. The four 20 watt

Mundorf`s amazing M-Resist™ SUPREME or Vishy 30W 1% non-inductive wire-wound resistors act as the load.


Power supply unit

This amplifier is powered with stabilized separate power supply, consisting of 300W transformer, 4 ultra fast shottky diodes MBR4060, low drop voltage regulator LM7824 and high quality electrolytic capacitors (Nichicon). The power is filtered using 40000µF capacitors model NICHICON – LLS1H103MELC

Technical data
  • Frequency response: 10 Hz – 100 kHz
  • Input put impedance: 10 kOhm
  • Output power: 7W continuous  avg. output power into 8 Ohm at VCC +27V ( With sensitive speakers > 92 dB )
  • THD+N:  <0.01 %


© Ratzov Tsenkov - Audio Design