The Orpheus Lab A Four I200 is a high-performance integrated stereo amplifier designed and manufactured in Switzerland. Drawing upon amplification technology developed for the company’s Heritage Opus II range, it combines a genuine dual-mono architecture with a sophisticated Class AB output stage delivering 200 watts per channel into 8 ohms. Each channel employs six individually matched high-power MOSFETs, controlled by bipolar transistor circuitry and a carefully implemented multi-point feedback topology. This arrangement provides precise control of the output stage, with instantaneous current delivery reaching 15 amperes and a damping factor exceeding 3,000, making the A Four I200 particularly capable of driving demanding loudspeaker loads.
Power delivery is supported by two independent 880VA toroidal transformers, each accompanied by 48,000µF of dedicated reservoir capacitance. A proprietary bias regulation circuit maintains stable operating conditions across changes in temperature and load, while the 125mA bias current establishes a carefully controlled Class AB operating point. The integrated preamplifier provides six analogue inputs with individually selectable sensitivity settings, allowing the amplifier to accommodate sources with different output levels. Precision volume control is handled by an optimised PGA2320 circuit, complemented by a dedicated low-distortion headphone amplifier. Combining substantial current capability, comprehensive connectivity and carefully engineered signal control, the A Four I200 provides a complete amplification solution for a wide range of high-performance audio systems.
Key Features
High-performance Class AB integrated stereo amplifier
Designed and manufactured in Switzerland
Part of the Orpheus Lab Absolute Series
Incorporates technology developed for the Heritage Opus II range
Rated output power: 200 watts per channel into 8 ohms
Genuine dual-mono amplifier architecture
Six individually hand-matched high-power MOSFETs per channel
Twelve high-power MOSFET output devices in total
Bipolar transistor control stage for each MOSFET
Proprietary multi-point feedback topology
High-current output stage capable of 15A instantaneous current peaks
Instantaneous peak power: 850W for durations below 200ms
Independently regulated output-stage biasing
125mA Class AB bias current
15W thermal idle dissipation per channel
Low-impedance BJT bias regulation circuitry
Stable bias operation across temperature and load variations
Two independent 880VA toroidal power transformers
Separate transformer for each audio channel
48,000µF dedicated reservoir capacitance per channel
Total power supply reservoir capacitance: 96,000µF
Six analogue source inputs
Balanced XLR and unbalanced RCA connectivity
Three selectable input sensitivity settings: High, Medium and Low
PGA2320 precision electronic volume control
Selectable signal grounding for unbalanced inputs
Dedicated headphone amplifier
Headphone compatibility from 32 to 600 ohms
High damping factor exceeding 3,000
Wide-bandwidth amplifier design
Protection against excessive output current
Protection against DC components at the loudspeaker outputs
Automatic muting during mains voltage interruption
The Orpheus Lab A Four I200 is a high-performance integrated stereo amplifier designed and manufactured in Switzerland. Drawing upon amplification technology developed for the company’s Heritage Opus II range, it combines a genuine dual-mono architecture with a sophisticated Class AB output stage delivering 200 watts per channel into 8 ohms. Each channel employs six individually matched high-power MOSFETs, controlled by bipolar transistor circuitry and a carefully implemented multi-point feedback topology. This arrangement provides precise control of the output stage, with instantaneous current delivery reaching 15 amperes and a damping factor exceeding 3,000, making the A Four I200 particularly capable of driving demanding loudspeaker loads.
Power delivery is supported by two independent 880VA toroidal transformers, each accompanied by 48,000µF of dedicated reservoir capacitance. A proprietary bias regulation circuit maintains stable operating conditions across changes in temperature and load, while the 125mA bias current establishes a carefully controlled Class AB operating point. The integrated preamplifier provides six analogue inputs with individually selectable sensitivity settings, allowing the amplifier to accommodate sources with different output levels. Precision volume control is handled by an optimised PGA2320 circuit, complemented by a dedicated low-distortion headphone amplifier. Combining substantial current capability, comprehensive connectivity and carefully engineered signal control, the A Four I200 provides a complete amplification solution for a wide range of high-performance audio systems.
Key Features
High-performance Class AB integrated stereo amplifier
Designed and manufactured in Switzerland
Part of the Orpheus Lab Absolute Series
Incorporates technology developed for the Heritage Opus II range
Rated output power: 200 watts per channel into 8 ohms
Genuine dual-mono amplifier architecture
Six individually hand-matched high-power MOSFETs per channel
Twelve high-power MOSFET output devices in total
Bipolar transistor control stage for each MOSFET
Proprietary multi-point feedback topology
High-current output stage capable of 15A instantaneous current peaks
Instantaneous peak power: 850W for durations below 200ms
Independently regulated output-stage biasing
125mA Class AB bias current
15W thermal idle dissipation per channel
Low-impedance BJT bias regulation circuitry
Stable bias operation across temperature and load variations
Two independent 880VA toroidal power transformers
Separate transformer for each audio channel
48,000µF dedicated reservoir capacitance per channel
Total power supply reservoir capacitance: 96,000µF
Six analogue source inputs
Balanced XLR and unbalanced RCA connectivity
Three selectable input sensitivity settings: High, Medium and Low
PGA2320 precision electronic volume control
Selectable signal grounding for unbalanced inputs
Dedicated headphone amplifier
Headphone compatibility from 32 to 600 ohms
High damping factor exceeding 3,000
Wide-bandwidth amplifier design
Protection against excessive output current
Protection against DC components at the loudspeaker outputs
Automatic muting during mains voltage interruption
