Duo 100.3 Dual Mono Class A Power Amplifier
Power and finesse all in one chassis

The Duo 100.3 Power amplifier has benefited from the substantial development that has gone into the ONE Integrated amplifier since its release in 2016. While the Duo 100.3 is based on the power amplifier section of the ONE Integrated amplifier it builds on that with a power supply that is more capable when dealing with demanding loudspeakers. When paired with the Pureaudio Control 2 preamplifier it is able to easily deliver a musical performance that is involving and highly satisfying.

The Duo 100.3 is a true dual mono design with entirely separate power supplies for left and right channels. Being housed in one chassis it is less demanding of installation space. The Duo 100.3 amplifier’s sonic signature is live and transparent with a hint of warmth. It is designed to work with domestic loudspeakers in typical home environments.

The Duo 100.3′s Class A Power rating is perfectly matched to this requirement and limits the energy consumption and the heat generated during operation in a true Class A design. The power rating also allows us to include a fully regulated, high-current power supply (a rare inclusion) providing an optimum low impedance, low noise environment from which the amplifier can deliver its very best.

Each channel of the Duo 100.3 Power Amplifier is biased for around 30 Watts Class A into 8 Ohms with headroom equivalent to 100 Watts. With Class A operation being somewhat inefficient we were conscious of the need to avoid excess energy wastage and so designed the amplifier to fall back automatically to a low power standby mode when not in use.

The amplifier’s Class A operation is automated through both signal sensing and 12V trigger connections. When partnered with our Control 2 Preamplifier via the 12V trigger circuit, Class A is activated when the preamplifier is brought out of standby.

Our universal chassis design, constructed from heavy aluminium, stainless steel mesh, and supported optimally on three custom designed feet, presents a beautiful architectural look and fully supports our musical goals.


Power: 100 Watts continuous into 8 Ohms
Frequency Response: Flat from 10Hz to 100kHz
Input Impedance: 82k Ohms
Distortion: Typically <0.01% under normal operation
Current Output: greater than 50A peak
Hum & Noise: Inaudible
Gain: 28dB
Control Terminals: 12V trigger in
Power Consumption Class A: 450 Watts
Dimensions: 410mm deep, 380mm wide, 155mm high
Weight: 24kg