Aurorasound PADA-300B Monoblock Amplifiers
The PADA-300B is Shinobu Karaki’s latest amplifier design, a hybrid push-pull monoblock built around the iconic 300B valve. Combining transistor precision with classic tube output, it delivers 28 watts per channel with a focus on musicality, stability, and long-term reliability.
Key features:
• hybrid push-pull monoblock amplifier
• 28 watts per channel output
• 300B output valves (various options available)
• transistor front-end with tube output stage
• inter-stage transformer coupling
• no negative feedback design
• AC-driven filament supply
• self-biasing circuit (no manual adjustment required)
• independent power regulators (front-end and output stage)
• silicon carbide Schottky diodes
• polypropylene film capacitors throughout
• vintage Japanese NEC and Toshiba transistors
• Lundahl transformers
• solid rosewood chassis with aluminium top plate
Design and performance:
Unlike conventional hybrid amplifiers, the PADA-300B reverses the typical architecture by using transistors in the front-end and valves in the output stage. This allows the amplifier to benefit from the low distortion, high signal-to-noise ratio, and wide bandwidth of transistors, while retaining the natural tonal qualities of 300B tubes.
An inter-stage transformer is used to match signal levels and provide the correct drive for the output tubes, ensuring efficient operation and preserving signal integrity.
The amplifier operates without a negative feedback loop, relying instead on the inherent linearity of the 300B valves and high-quality transformers to achieve a natural and open sound.
Materials and construction:
• vintage NEC and Toshiba transistors from the 1970–80s
• Lundahl transformers for signal integrity
• silicon carbide Schottky diodes for low-noise rectification
• polypropylene film capacitors for stability and longevity
• separate regulated power supplies for front-end and output stage
The use of independent power regulation ensures that demanding musical passages do not affect the stability of the input stage, maintaining control and dynamics under load.
Sound characteristics:
• natural, open and spacious presentation
• strong dynamic control with stable power delivery
• low noise with high clarity
• rich tonal character from 300B output stage
• excellent balance between precision and warmth
The push-pull design allows the amplifier to deliver power with control while maintaining the tonal qualities associated with single-ended 300B designs.
Build and craftsmanship:
The chassis is constructed from 25mm thick solid oiled rosewood, handcrafted in Japan, providing both structural rigidity and resonance control. The top plate is made from 4mm thick solid aluminium, offering a non-magnetic platform for the circuitry.
Each unit reflects Aurorasound’s approach of combining traditional materials with carefully selected components to achieve both performance and durability.
Note:
The PADA-300B is supplied as a pair of monoblock amplifiers. Valve options include Takatsuki 300B or Western Electric 300B, or units can be supplied without valves depending on system requirements.
