Интегральные усилители — Soulnote A-1

The A-1 is an integrated amplifier made in Japan by Soulnote and released as the 10-year anniversary model of the brand, sold in Platinum Silver or Black. It is built on the Soulnote approach of perfectly balanced discrete circuits without negative feedback, and for this model the engineers re-examined every small detail of that topology, from the star wiring of the ground plane to the direct coupling routes. Volume, power supply and mechanical design were all reworked around the same idea of a short and uninterrupted signal path.

Key specs that matter

Maximum output is 80 W x 2 into 8 ohm and 120 W x 2 into 4 ohm. Total harmonic distortion is 0.08 percent measured at 30 W into 8 ohm, and the frequency characteristic runs from 3 Hz to 300 kHz within 1.0 dB. Signal to noise ratio is 110 dB with the IHF A network. There are four line inputs, all rated at 700 mV sensitivity. LINE 1 is the balanced input with an impedance of 16 kohm, while LINE 2 to 4 present 8 kohm. Power draw is 190 W at full output and 90 W at idle, and the export version runs on 220 V AC at 50 Hz. The case measures 456 x 109 x 418 mm and weighs 11.0 kg.

Engineering and use context

Even the supply section is discrete and free of feedback, and it is fed by a newly developed large capacity toroidal transformer with bifilar windings, using independent windings for the positive and negative rails. Soulnote removed every kind of connector from the signal system, so the construction is completely contactless between input and output. Instead of a conventional rotary potentiometer or an electronic volume chip, the A-1 uses a balanced attenuator that switches precision resistors by relay. Spikes are fitted beneath the centre of gravity of the transformer, a direct mechanical grounding method meant to lead harmful vibration straight out of the chassis. The housing is laid out symmetrically with attention to resonance control, and metallic insulators come as standard equipment. Spikes and a power cord are packed with the amplifier.

Pairing

The single balanced input suits a converter or disc player with XLR outputs, such as the Soulnote S-3, while the three unbalanced inputs cover other line sources. The remote control handles volume from the listening seat, and the relay attenuator keeps that adjustment within the balanced circuit.

Alternatives

The Soulnote A-2 sits above it in the Soulnote integrated range, delivering 100 W per channel and offering a bridged mono mode.