鳴神 NARUKAMI – Pursuing the Purity of Sound
Named after “NARUKAMI”, this headphone amplifier/pre-amplifier, “HPA-KG NARU” has been carefully crafted to capture the intricate details and emotional depth of sound, offering a unique, refined, and natural listening experience. NARUKAMI intertwines the majesty of nature with human innovation, combining Audio-Technica's expertise - over 60 years of pursuing the purest analog sound – with the transcendent aesthetics of KUROGAKI, an ancient wood treasured by Japanese nobles and literati with a rare, ink wash painting-like pattern.
“HPA-KG NARU” is not just a headphone amplifier; it also serves as a preamplifier with output functionality. It can drive power amplifiers using the signal from the output transformer driven by TA-300B vacuum tubes, making it suitable for use as a preamplifier for speakers.
To accompany the amplifier, a limited-edition NARUKAMI Headphones “AW-KG NARU” has been exclusively designed with the same KUROGAKI wood housing as the amplifier, featuring specially tuned sound characteristics. Each set comes with a custom-made headphone cable, ensuring an exceptional listening experience. The output transformer features a headphone matching circuit with three impedance positions, allowing users to choose the impedance that best suits their headphones' characteristics and desired sound quality.
The amplifier also features a convenient volume balance control knob, allowing users to adjust the volume balance between the left and right channels according to their individual preferences and requirements, and provides a 4.4mm XLR 4-pin balanced headphone socket, as well as a 6.3mm single-ended headphone socket, ensuring true versatility.
Pursuit of Pure Audio | A Decade of Discovery
In a true pursuit of pure audio, Audio-Technica spent ten years developing eleven different prototype iterations for the NARUKAMI amplifier. The team pushed the potential of natural audio reproduction to new limits, testing parameters that couldn't be measured with existing instruments. Experimenting with every element of the amplifier: circuitry, components, and structural variations; they had to rely on their auditory expertise, as they built upon layers of accumulated knowledge to progress further.
The circuit design incorporates the use of the finest components available. This includes:
- Lundahl's LL1532 input transformer.
- Custom-made Lundahl Amorphous Core Silver Wire Output Transformer LL2765AgAM, offering extremely low magnetic hysteresis loss, high saturation magnetic flux density, and excellent frequency response.
- High-quality TAKATSUKI TA-300B vacuum tubes handcrafted in Japan, carefully selected specifically for headphone amplifiers for robust driving power and high-quality sound.
- AmTrans's premium audio aluminum shell resistor with exceptional heat dissipation properties.
- Custom-designed power transformer for independent power supply to L/R channels by Someya Denshi.
- SRPP circuit with rare JJ ECC83S-gold vacuum tubes, providing a rich and flavorful sound.
The circuit design of the NARUKAMI Amplifier features a luxurious configuration with four circuits, each consisting of a balanced arrangement of HOT and COLD sides for the left and right channels. The current supplied to the left and right audio signal circuits is sourced from dedicated power transformers, ensuring stable and pure current delivery. This design achieves high separation and low noise, resulting in transparent and rich sound quality. With such a design, the NARUKAMI Headphone Amplifier achieves exceptional music playback capabilities, aiming to satisfy even the most discerning audio enthusiasts.
All input switching and output transformer switching are achieved through sealed relays, ensuring durability and stability. The use of relays also enables the optimization of signal flow for enhanced performance.
Embodying Japanese Nature and Craftsmanship
This same meticulous approach was applied to the aesthetics of the NARUKAMI amplifier; integrating the art of Japanese rituals and philosophies so that the finished product embodied Japanese nature and craftmanship. The amplifier's name, “NARUKAMI”, derives from the deity of thunder and lightning in traditional culture. This thunder god is often depicted striking drums, replicating the roar of thunder, and symbolizing the power and vitality of sound.
The designers of the amplifier and headphones were inspired by the fusion of two quintessential spaces in Japan – karesansui (landscape gardens) and tatami rooms – symbols of peace, discipline and coexisting in harmony with nature.
The housing features KUROGAKI wood, an elusive natural wonder that has developed a distinctive ink wash painting-like marking over centuries. KUROGAKI must be handled by skilled workers who are familiar with the wood's complex drying process. Intricate ripples adorn the top of the amplifier, these represent “Karesansui”, or traditional Japanese garden landscaping. This pattern cascades down both sides of the amplifier, creating a flowing motion and replicates both the symbol of infinity (∞) and the number 8, which is auspicious in Asian culture.
The metal mesh cover used to protect the vacuum tubes and output transformers features an “Ayasugi” pattern, these represent the needle arrangement from the dark green Japanese cedar tree – a natural phenomenon cherished by Japanese culture and seen in many traditional designs.
Commenting on the new NARUKAMI amplifier President of Audio-Technica, Kazuo Matsushita, said: “Since 1962, analog sound has been at the heart of Audio-Technica. NARUKAMI represents the continued pursual of pure audio. Every exclusive element of this amplifier was selected with consideration and care – from the Lundahl transformers to the KUROGAKI wood – continuing to push the potential of audio reproduction to new heights. This unique listening experience will deepen our emotional connection to sound.”
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Further Information on the Technical Components
The Lundahl output transformers LL2765AgAM are constructed with amorphous alloy cores, which are different from conventional cores, offering extremely low magnetic hysteresis loss, high saturation magnetic flux density, and excellent frequency response. The cores are meticulously wound with high-purity silver wire, providing very low resistance and outstanding conductivity.
This design is used to match the impedance between the output transformers of the vacuum tube amplifier and the headphones, offering optimal impedance matching. This allows the amplifier to deliver greater power to the headphones, adding richness to the sound and maintaining excellent frequency response.
In addition, the output transformer features a headphone matching circuit with three impedance positions, allowing users to choose the impedance that suits their headphones' characteristics and desired sound quality.
The TA-300B vacuum tube is meticulously handcrafted in Japan and known for its exceptional performance and sound quality. It features plates that are pressed with dedicated molds, filaments designed and manufactured using special techniques, and highly precise grids. It offers a rich midrange and natural high frequencies without being overly bright or harsh on the ears. The low frequencies are compact, clear, and exhibit excellent extension and rich details. To prevent hum and other noise from entering the signal, the TA-300B employs a complex DC filament biasing method and undergoes multiple filtering stages to purify the filament power supply, resulting in low noise performance.