Интегральные усилители — ToneWinner AD-2PRO+

The AD-2PRO+ is an integrated amplifier from Tone Winner, the Chinese manufacturer based in Guangzhou. It is the latest development of the AD-2, refined over some twenty years, and its fully balanced circuit can run in pure Class A, in Class AB, or in an automatic mode that switches between the two, selected from the remote. It also includes a DAC with USB input and an MM/MC phono stage.

Key specs that matter

Output is 240 W per channel into 8 ohms in Class AB, with about 60 W per channel in pure Class A. Frequency response runs from 15 Hz to 95 kHz, signal-to-noise exceeds 100 dB and THD is 0.05% or lower (1 kHz, A-weighted). Analogue inputs are one balanced XLR and three RCA, plus MM/MC phono. Digital inputs comprise two optical, one coaxial and USB, handled by an ESS ES9038 DAC supporting PCM to 32-bit/768 kHz and DSD512. Subwoofer outputs are provided on balanced and unbalanced connectors. The chassis measures 444 x 254 x 460 mm and weighs 35.9 kg.

Engineering and use context

Symmetry runs through the whole signal path, from a differential input through to a bridge-tied load output stage, in which each speaker is driven by two amplifier sections in opposite phase. The left and right channels have independent power supplies built around 860 W toroidal transformers and 120,000 uF of audio-grade filter capacitance, with high-power output transistors in parallel for current capability. Nine Texas Instruments OPA1656 operational amplifiers form the balanced gain stages of the preamplifier and DAC sections. In Class A mode the output transistors conduct over the full signal cycle, which removes crossover distortion but limits output and raises heat, while Class AB mode provides full power. The automatic setting moves between the two according to signal level. A remote-selectable power amplifier mode bypasses the volume control for use with an external preamplifier or AV processor. Large heatsinks and a patented wide-voltage power design complete the build, accepting mains from 110 V to 240 V.

Pairing

The Class AB rating handles low-sensitivity floorstanders in rooms up to about 40 m2, while Class A mode suits efficient speakers of 90 dB or more. The subwoofer outputs support 2.1 systems, and the weight of the chassis calls for a sturdy shelf.

Alternatives

Tone Winner's AD-3PRO+ is the smaller integrated amplifier with 165 W per channel and a DAC section.