Усилители мощности стерео — Audio Analogue AA100DM

The AA100DM is a fully balanced stereo power amplifier without global feedback from Audio Analogue, the Italian brand made by AF Group Srl in Monsummano Terme, which also owns Airtech. It is the latest addition to the PureAA line, and its power stage is derived from the Puccini Anniversary, with higher output. The amplifier can also be bridged into a mono amplifier with a dedicated connection kit.

Key specs that matter

With one channel driven at 1% THD, output is 100 W into 8 ohm, 200 W into 4 ohm and 320 W into 2 ohm. In bridged mono it delivers 400 W into 8 ohm and 700 W into 4 ohm. Signals enter through RCA or XLR sockets, both presenting 47 kOhm, and gain is 26 dB, with 1.4 V RMS needed for full output into 8 ohm. Bandwidth reaches 95 kHz at -3 dB, output resistance is 0.25 ohm, input noise is about 3 µV A-weighted and signal to noise ratio exceeds 110 dB A-weighted. Standby consumption is 0.5 W. The amplifier measures 445 x 120 x 390 mm and weighs 15.5 kg, in natural aluminium or satin black.

Engineering and use context

The circuit is dual mono and built from discrete components, with oversized through-hole military-standard resistors, chosen to limit thermally induced distortion, and polypropylene capacitors. A 760 VA transformer powers both channels, and each channel uses three pairs of On Semiconductor output transistors. Internal wiring is solid 7N OCC copper, and the output terminals are gold-plated. Audio Analogue works without global feedback and states that this makes the amplifier less sensitive to the load, with no oscillation, no high-frequency resonance peaks and no saturation of the input stage. Being fully balanced, the amplifier handles each channel as a differential pair of signals all the way from the XLR socket to the speaker terminals, and single-ended RCA signals are converted at the input. Output rising as the impedance falls shows that the supply keeps up as the load impedance falls. The low output resistance corresponds to a damping factor of about 32 into 8 ohm. Overtemperature protection for each channel shuts the amplifier down automatically, and the number of blinks of a front LED identifies the fault. Audio Analogue asks for at least 30 cm of free space around and above the unit for ventilation.

Pairing

The AA100DM suits most passive loudspeakers, low-impedance designs included, and a pair bridged to mono, with the kit bought together with the second unit, serves demanding loads. Audio Analogue's ABsolute line preamplifier and other balanced preamplifiers connect through XLR, and the gain matches standard preamplifier output levels.

Alternatives

The Audio Analogue Donizetti is the power amplifier of the brand's Anniversary line.