Effectively a fusion of the Orpheus Two preamplifier in its pure stereo configuration and the Orpheus Three S stereo power amplifier, the Orpheus Four integrated amplifier offers special advantages, including a preamplifier bypass function that allows it to be run as a power amplifier without signal attenuation. This convenient feature, for use in a system with a surround processor or source component with built-in volume control, eliminates a superfluous volume potentiometer from the signal path and maintains the integrity of the audio signal.

Operating far below any audible threshold, the exclusive Orpheus Power Loop power amplifier module reacts instantaneously to ensure pristine clarity and control. Based on proprietary Orpheus technology, Power Loop monitors both voltage and current, executing corrections as required at extreme high speeds for rock-solid stability to maintain the purity of the audio signal, regardless of loudspeaker load. In the presence of a resistive load, Orpheus Four acts as a voltage amplifier. In the presence of a reactive load, the load is controlled during transients and current is adjusted to meet the requirements of the loudspeaker.

The ultra-quiet Orpheus amplification stages ensure an exceptionally low noise floor, allowing music to float free and unimpeded before the listener.

The Orpheus Four is able to “track” dynamic passages with all of the subtle ebb and flow of the drama intact. It releases notes quicker, infusing the music with life and vibrancy. The speed and agility of its transient response bring new levels of realism to any style of music.
The result is a scintillating experience of a multi-dimensional soundstage that always retains appropriate focus on individual voices and instruments.

Designed to fit a single rack unit (482 x 370 x 44 mm), each Orpheus component employs an ultra-compact signal path layout for significant gains in audio performance.

The green dot-matrix display features an input naming function that allows the owner to customize names up to ten characters long for each source component.

The display’s five user-selectable levels of illumination from full brightness to OFF.

In conjunction with the front panel display, Orpheus’ specially developed menu navigation system becomes an ingenious communications centre for efficient, intuitive control with minimal fuss.

Features:

• 2 x 40 Watts
  
• Preamplifier bypass (unattenuated throughput) option for use as power amplifier
  
• 1 balanced XLR input, 4 single-ended phono inputs
  
• Low-noise relay input switching
  
• 80-step volume control in precise 0.5 dB increments
  
• 40-step relative level adjustment for each input in 0.5 dB increments
  
• Intuitive menu-based operation
  
• Channel balance control
  
• Efficient heat dissipation via internal chassis-coupled heatsinks
  
• User-selectable input names up to 10 characters
  
• User-adjustable display lighting

This is a 2003 unit (with a green display). It has been used for 4-6 hours only.

To learn more about the brand you might go to www.orpheuslab.com