Real class-AB discrete transistor amplifiers made small. 45 watts into 4 Ω; 25 watts into 8 Ω. With rugged 15 amp 200 watt output transistors the Proprius drives even the most difficult of speakers.
With volume controls that go all the way, these power amps can be driven by a separate preamp (for example: the excellent Majestic pre-DAC in the picture above) by parking the volume at full — or their own volume controls can be used in a minimalst system driven by a fixed output source.