SoulNote A-1 ver.2: A Purist's Amplifier with Flagship DNA

SoulNote has unveiled the A-1 ver.2, an integrated amplifier that, while building upon the core foundation of the original 1-Series, incorporates key technologies and design philosophies from the development of the company's flagship 3-Series. The result, according to the esteemed Japanese manufacturer, is nothing short of a "dramatic evolution" in sonic performance.

At its heart, the A-1 ver.2 is an integrated amplifier delivering a confident 40 watts per channel into 8 ohms, doubling to 80 watts into 4 ohms. The power stage is a testament to purist design, featuring a single push-pull output stage built around large TO-3P, low-C(ob) high-power transistors. This configuration, realized in a four-stage Darlington arrangement, is engineered to eradicate tonal ambiguity and deliver an authoritative, commanding grip over the loudspeakers.

True to SoulNote's core principles, the A-1 ver.2 employs a fully discrete, zero-feedback (No-NFB) circuit topology. The architecture is elegantly minimalist, mirroring that of the flagship A-3 amplifier by integrating only the source selector and volume control directly with the power amplification stage. This direct-path approach is designed to preserve the utmost freshness and integrity of the original music signal.

Significant advancements have been made in the circuitry. A newly developed bias circuit replaces the previous LED-based design, leading to a substantial improvement in the signal-to-noise ratio. The layout itself is meticulously designed to eliminate CR (capacitor-resistor) resonance. By utilizing ultra-high-quality resistors that maintain stable impedance even at high frequencies, SoulNote achieves a sound that is remarkably transparent and stable, all without artificially limiting the amplifier's bandwidth.

The power supply is anchored by a newly developed, non-potted toroidal transformer. In a strategic design choice, SoulNote has deliberately lowered the secondary output voltage—which defines the amplifier's maximum power ceiling—to enhance its current delivery capability. The company states this allows the A-1 ver.2 to exhibit an "exhilarating and agile drive with astonishing authority," even when faced with the challenging low-impedance loads of modern high-end speakers.

Connectivity is comprehensive, with two sets of balanced XLR inputs and two sets of single-ended RCA inputs. Following the precedent of its predecessor, both input switching and volume attenuation are managed by high-quality relays, with the latter employing a precision resistor-ladder attenuator for pristine level control.

Specifications at a Glance:

• Power Consumption: 130W (J60065 standard), 40W at idle.

• Dimensions (W×D×H): 430 × 418 × 109 mm

• Weight: 10 kg

For audiophiles seeking an entry point into the SoulNote ecosystem, the company also announced a more accessible integrated amplifier, the A-0 ver.2, scheduled for a December release in Japan at an approximate price of ¥181,500 JPY.