Addressing some of the shortcomings of the traditional Marantz 7 circuit, Japanese engineer Shigeru Wada made improvements based on the Marantz 7 circuit, and the improved circuit is known as the Wada Shigeru circuit. Its main feature is the replacement of the cathode follower in the Marantz 7 circuit with an SRPP circuit. Since the SRPP output stage does not have any voltage amplification function and is only used as a buffer stage, it has stronger load driving capability compared to ordinary cathode output stages. In terms of sound quality, it retains the sweet and mellow mid-frequency characteristics of the Marantz 7 circuit, with higher analytical power. The low-frequency response is better than that of the Marantz 7, and the signal-to-noise ratio is relatively high. All the electronic tubes used in this circuit can also be replaced with 12AT7.
The product requires no debugging and can be used without installation errors. The PCB is double-sided tinned, and the resistor is Beijing 718. The coupling is either from Siemens or ERO. The kit includes 2*6Z4 rectifier tubes, while 4*amplifier tubes need to be purchased separately.
PCB size: 155X122MM
To clarify, this circuit uses full DC for the filament. The high voltage is also equipped with voltage regulation and filtering, ensuring absolutely quiet noise. However, it is important to note that the input impedance of the electronic tube is high, so the input must be shielded. It is also recommended to ground the chassis to keep noise levels extremely low. If you encounter any manufacturing issues, feel free to communicate with us for resolution.
