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A power amp.
With a selector attached.

The Soulnote A-2 ver.2 is a completely non-NFB integrated amplifier — four amplifiers in one, built around as little else as possible.

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Nothing in the way

mu — nothing added

Everyone adds.
Soulnote subtracts.

The best producers know the secret: the art is what you leave out. Soulnote engineers the same way — every stage a conventional design adds to the signal path is a chance to blur the original waveform, so Soulnote removes them, one by one, and tunes what remains by ear.

Between input and output: 4 extra stages, each with a fingerprint. Between input and output: almost nothing.

Every stage does a job — and leaves a fingerprint on the waveform as it passes through.

Fewer hands on the signal. What remains was chosen by listening — part by part.

Designed by subtraction

Less circuit.
More music.

80W

into 8 ohms (160 W into 4 ohms) — current-first power for tough loudspeaker loads.

4modes

stereo integrated, bi-amp mono, stereo power, or bi-amp mono power — one amplifier, four roles.

70micron copper

on a four-layer PCB, with connectors eliminated from the signal and power paths.

Technical specifications
TypeIntegrated amplifier, completely non-NFB, fully balanced
Power output80 W × 2 (8 ohms); 160 W × 2 (4 ohms)
Output stageParallel push-pull, hFE-matched high-speed TO-3P transistors
Volume controlRelay-switched balanced attenuator, high-precision resistors
ModesStereo integrated / bi-amp mono integrated / stereo power / bi-amp mono power
THD0.16% (1 W, 8 ohms)
Frequency response3 Hz – 240 kHz (±1.0 dB)
Signal-to-noise ratio110 dB (IHF A)
Dimensions430 × 160 × 423 mm
Weight~20 kg
What are the four modes of the A-2 ver.2?
Stereo integrated, bi-amp monaural integrated, stereo power amplifier and bi-amp monaural power amplifier. In the power-amp modes the microcomputer, selector and volume are bypassed entirely, which is why the signal-to-noise ratio rises.
How much power does it deliver?
80 watts per channel into 8 ohms and 160 into 4. The transformer runs at a deliberately lowered voltage so the amplifier trades a headline 8-ohm figure for the instantaneous current that difficult, low-impedance loudspeakers actually draw.
Why is the top cover loose?
By design. The cover floats and the circuit board is left unsecured so vibration is released instead of stored in the chassis. Leave it as it arrives.
About the Soulnote A-2 ver.2 Integrated Amplifier

Availability: Ships in 10–15 business days.

No Feedback, No Compromise: Soulnote A-2 ver.2

Founded by ex-Marantz engineer and director Norinaga Nakazawa, Soulnote designs "100% based on the actual sense of hearing" — and the Soulnote A-2 ver.2 is that philosophy at full volume. This is a completely non-NFB integrated amplifier: no global feedback loop of any kind, prioritising signal purity above tidy measurements. Nakazawa's team describes it, only half-joking, as "essentially a power amplifier equipped only with a selector and volume control." The result is the vivid, alive, three-dimensional sound that has made Soulnote a cult name among Japanese high-end enthusiasts.

Purist Circuitry, Obsessive Build

The A-2 ver.2 delivers 80 watts per channel into 8 ohms (160 W into 4 ohms) from a parallel push-pull output stage using high-speed TO-3P transistors precisely paired by hFE to eliminate the tonal smearing common to conventional designs. A four-stage Darlington driver gives it exceptional grip, while a non-impregnated large toroidal transformer runs at deliberately lowered voltage — trading maximum 8-ohm wattage for the instantaneous current that really matters into demanding, low-impedance loudspeakers. Everywhere you look, sound quality drives the engineering: a four-layer PCB with 70-micron copper, cables soldered directly to the boards with connectors eliminated from both signal and power paths, a chimney-type heatsink, and even a floating top cover and unsecured circuit board to keep vibration away from the music.

One Box, Four Amplifiers

A relay-switched balanced attenuator with high-precision resistors handles volume, sharpening imaging and low-level detail. And the A-2 ver.2 is really four amplifiers in one: use it as a stereo integrated, a bi-amp monaural integrated, a stereo power amplifier, or a bi-amp monaural power amp. In power-amp mode it bypasses the microcomputer, selector and volume entirely for the highest possible signal-to-noise ratio — a genuine upgrade path as your system grows.

Why You'll Love the Soulnote A-2 ver.2

  • Completely non-NFB design — no global feedback, for vivid, natural, alive sound
  • 80 W into 8 ohms (160 W into 4 ohms) — current-first power supply for tough loads
  • hFE-matched parallel push-pull — high-speed TO-3P output devices, no tonal smearing
  • Relay balanced volume — high-precision attenuator for pristine low-level detail
  • Four amplifier modes — integrated, bi-amp mono, stereo power, bi-amp mono power
  • Sound-first construction — direct-soldered wiring, floating cover, four-layer PCB
  • Hand-built in Japan — Premium Silver or Premium Black, ~20 kg of engineering

Frequently Asked Questions

What does "non-NFB" mean, and why does Soulnote use it?

NFB stands for negative feedback — a technique most amplifiers use to lower measured distortion. Soulnote omits any global feedback loop because founder Norinaga Nakazawa believes it robs music of life and immediacy. The A-2 ver.2 is tuned entirely by ear, prioritising a vivid, three-dimensional sound over textbook numbers.

Can the A-2 ver.2 be used as a power amplifier or in bi-amp mode?

Yes. It offers four modes: stereo integrated, bi-amp monaural integrated, stereo power amplifier, and bi-amp monaural power amplifier. In power-amp mode it bypasses the selector and volume control for the highest signal-to-noise ratio.

Will it drive difficult speakers?

Its power supply is deliberately engineered for instantaneous current into low-impedance loads, and the four-stage Darlington driver gives strong control — so despite its "80 watt" rating it grips demanding speakers with authority.

Soulnote A-2 ver.2 Technical Specifications

Type Integrated amplifier, completely non-NFB, fully balanced
Power output 80 W × 2 (8 ohms); 160 W × 2 (4 ohms)
Output stage Parallel push-pull, hFE-matched high-speed TO-3P transistors
Volume control Relay-switched balanced attenuator, high-precision resistors
Modes Stereo integrated / bi-amp mono integrated / stereo power / bi-amp mono power
THD 0.16% (1 W, 8 ohms)
Frequency response 3 Hz – 240 kHz (±1.0 dB)
Signal-to-noise ratio 110 dB (IHF A)
Power supply Non-impregnated large toroidal transformer
Construction Four-layer 70 µm PCB; direct-soldered wiring; chimney heatsink; floating top cover
Dimensions (W × H × D) 430 × 160 × 423 mm
Weight ~20 kg
Finishes Premium Silver or Premium Black
Made in Japan — Soulnote