Boutique HiFi Concierge
For product demonstrations in-studio (by appointment) or in the comfort of your own home, call Greg Chapman on 0333 577 2005 or 07717 477 994 or email to find out how VAL HiFi can help you.
Brand Aurorasound
Aurorasound is a company from Yokohama, Japan. Designer and director Shinobu Karaki has over 28 years of experience working for Texas Instruments Japan Inc. He is also a passionate musician, music teacher and a first-grade audiophile for many years. His love of music, trained ears and extensive know-how in electronics and integrated circuits make Mr. Karaki the ideal person to design high-end audio devices.
Shinobu Karaki-san's developments and designs are state-of-the-art innovative semiconductor technology and, combined with old-world craftsmanship, make his amplifiers very special and highly sought after.
VAL HIFI RECOMMENDS
HFSA-01 is a hybrid pre-main amplifier, cleverly harnessing both vacuum tubes and semiconductor technology to deliver the best of both worlds.
The EL84 tube delivers 14W + 14W power output.
After 10 years on the market Karaki-san released a new, improved version of his outstanding, highly praised phono stage - the Aurorasound VIDA Mk.II.
The exterior design has not changed much. Internal circuit, PCB, PSU, specifications and sonic performance have been refined. Among other things the L/R channel separation improved +6dB, THD+N factor improved from 0.028% to 0.012%, new amp modules (gold-plated, developed for the VIDA Supreme), inputs for 2 MC or 2 MM cartridges at the same time (or 1 each) and the US version now comes standard with a 6 position impedance selector switch for MC on the backside.
State of the art semiconductor technology (LCR-type network) and innovative technology combined with old-world craftmanship makes this phono amplifier outstanding in many respects.
Key features:
Adopted LCR type RIAA device. Unlike conventional NF & CR type for RIAA curve, VIDA uses L (coil) to generate precise RIAA curve, resulting in much fulfilling midranges
With use of the latest semiconductor devices and discrete amplifier circuit, it achieved a complete DC circuit design. As a result, capacitors in the signal path were completely eliminated
High resolution in the low frequencies and reduced distortions, it enables you to enjoy vivid music hall atmospheres coupled with the players positioning on the stage
A large-size MUTE switch together with other functions are aligned in the front panel for improved man-machine interface for user-friendly operation
High S/N ratio was achieved with use of an external power supply unit, having extremely stable and super low-noise and high–speed circuits
Compatible with MC and MM type cartridges. High/Low Impedance Selector switch on the front panel.
Shinobu Karaki-san's latest masterpiece - the PADA-300B hybrid, push-pull, mono block amplifiers utilizing replicas of the original WE300B valves with an output of 28 Watts per channel.
Design Philosophy
Conventional hybrid power amplifiers are constructed using vacuum tubes in the front-end and transistors for the output stage, the transistors doing the power amplification with the tubes just adding a flavor of the classic tube sound.
However, the PADA-300B is designed in the opposite way – the transistors in the front-end and the tubes for the output. The PADA-300B design leverages the transistors to achieve low distortion, high SNR and wide frequency range, and then utilizes an inter-stage transformer to drive the output tubes. The inter-stage transformer matches the signal level and supplies the voltage difference between the transistors and tubes. This construction makes optimum use of both the advantages of transistor performance as well as the warm tube sound.
Noise Prevention and Control
Thanks to the excellent linearity of the 300B tubes and Lundahl transformers the PADA amplifier has no negative feedback loop. The tube filament is driven by AC voltage. In many of today’s conventional amplifiers, DC filaments driven by high-current diode devices is used because of its low cost, which often results in low hum noises. DC-driven filaments have other disadvantages, such as unevenness of electron emission in the filament wire due to its resistance factor, which can damage tubes in long term use. PADA-300B AC drive technique cancels hum noise thanks to its push-pull design and simple center adjustment by its pod trimmer. AC is by far the best method for achieving optimum performance from 300B tubes.
Self-Biasing
The PADA-300B employs self-bias methodology for operating the tubes, providing long-term stability. The user can change to different brands of 300B tubes by simply plugging them in - no need to re-adjust bias current with a monitoring meter. Self-biasing circuits usually use electrolytic capacitors due to need of large capacitance and small footprints. The PADA-300B, however, uses highly reliable precision polypropylene film capacitors, taking advantage of their superior high frequency response and longer lifetime in high temperatures.
Front End Circuitry
The PADA-300B’s frond-end circuit utilizes NEC and Toshiba Japanese transistors that were developed especially for audio applications from 1970-1980, the golden age of analog audio. Those transistors have been discontinued due to lack of demand in the digital era, but have excellent audio performance compared to the current chip-sized transistors made in China. Aurorasound has a large quantity of new-old-stock of those Japanese transistors from the 70’s and utilizes them in all Aurorasound products.
Power Supply
The PADA-300B’s power supply section has independent regulators for both the front-end and output stage. The front-end regulator Is the same high quality regulator as the Aurorasound VIDA’s, which ensures stability and low noise. The output stage regulator uses super-low-noise silicon carbide Schtokky diodes with large size film capacitors instead of common electrolytic capacitors, once again taking advantage of their superior high frequency response and longer lifetime in high temperatures as in the self-biasing components.
Output Stage
In general, when music plays in fortissimo (very loud) or sequential percussive phrases, common output stages consume a large amount of current power, causing the front-end to suffer. However, PADA-300B system of independent regulators prevents this from happening, managing dynamics extremely well.
Chassis
The chassis consists of 25mm thick solid oiled Rosewood, hand made by a woodworking artisan in Japan’s Shizuoka prefecture, home of Mount Fuji. This rosewood is used for finger boards and sides of acoustic guitars, in which it provides a very robust foundation to support the guitar top board and strings. The effect of the rosewood on the PADA-300B’s is the same as that of the guitar construction. The top of the PADA-300B is made of 4mm thick solid aluminum, a completely anti-magnetic material.