The audio note 300B power amplifier has been reborn with the latest knowledge on traditional circuits.
Input stage is plate follower and direct connection cathode follower by 6072. Classic type phase inverter circuit is chosen for good balance of naturalness. 300B power tubes are fully driven with low impedance by 6CG7 in parallel configuration.
By suppressing overall NFB to only 2 dB, a new level of dynamic and low distortion is achieved. Sound quality is also improved through adding high quality resistors in combination with the VR of hum balancing circuit. 300B output stage is self-biasing circuit. This help owner to replace various kind of vintage 300B without stress.
Smart modular design and shortest wiring set good foundation for Gakuoh II's long durability with good sound.
High sound purity is obtained through independent rectification circuits for both amplification stage and output stage. Decoupling capacitors are installed close to each ripple filters to form clean signal loops. This design strongly reduced the inter-stage interference to minimum.
Using 2 pieces of rectifier tubes in parallel raise instantaneous current performance of the output stage. The rectifier tube is chosen with sound quality as prime concern. Independent power transformers are used to source clean high current to the heaters of the rectifier tubes.
Based on a full copper chassis, all premium grade parts are employed through listening tests. New design silver output transformers using in-house winding technique, Kagura generation silver signal capacitors, silver lead resistors, internal silver wiring materials SSW (silk silver wire), Ls-41 flagship interconnect, low vibration molded power transformer are all applied. All parts, including C and R, are placed at their optimized position.
|Product||300B Push-Pull Monaural PowerAmplifier|
|Rated power||20W @1kHz, 5% THD|
|Frequency response||10Hz ～ 40kHz (+0dB, -3dB @1W)|
|Input / Impedance||RCA, XLR (unbalanced) / 70kΩ|
|Output||4Ω, 8Ω, 16Ω (2 outputs factory preset)|
|Noise||Less than 1mV|
|Vacuum tube||300B x2, 6CG7 x2, 6072 x1, GZ34 x2|
|Dimension||294mm(W) 284mm(H) 485mm(D)