To address some shortcomings of the traditional Marantz 7 circuit, Japanese engineer Shigeru Wada improved upon the original design, resulting in what is now known as the Wada Shigeru Circuit. The key enhancement involves replacing the Marantz 7's cathode follower with an SRPP circuit. The SRPP output stage does not provide voltage amplification but serves as a buffer, offering superior load-driving capability compared to a standard cathode follower. In terms of sound quality, it retains the sweet and rich midrange characteristic of the Marantz 7 while delivering better resolution, improved high and low-frequency response, and a higher signal-to-noise ratio.
Those familiar with the Wada Shigeru tube preamplifier know its standout feature is the prominent and well-defined midrange, especially for vocals. This is attributed to the even-order harmonic distortion produced during tube operation. Unlike odd-order harmonics, even-order distortion does not degrade the listening experience; instead, it enhances the sound's richness and adds a pleasing texture, making certain details more pronounced—almost as if they have been subtly optimized. When playing vocal tracks, the sound carries an emotionally rich and deeply "tubey" character. This unique tonal quality isn't limited to vocals; it also imparts a distinct style when reproducing intimate musical pieces, such as chamber recordings of violin, saxophone, jazz, and similar genres.
The unit is built with premium materials, featuring a titanium gold stainless steel chassis, a solid North American walnut front panel, solid aluminum knobs, a dynamic VU meter, and a protective cover for the glass tubes.
Power is supplied by dual E-core transformers, with separate high and low voltage circuits to prevent interference and ensure a clean audio output.
Internally, the components are of audiophile grade: a Japanese ALPS (Model 16) volume potentiometer, German WIMA audio capacitors, British AV audio capacitors, Tianji oil-immersed coupling capacitors, Black Gate/Changxing/VENT high-end electrolytic capacitors, high-quality ceramic tube sockets, and gold-plated pure copper RCA connectors.
To guarantee superior sound quality, the unit employs six imported premium tubes and utilizes dual-tube rectification for a warmer, more authentic tube sound. Four imported 6H3N triple-mica tubes provide a solid foundation for exceptional audio performance.
For enhanced user convenience, an optional built-in digital streaming decoder board (valued at over a thousand yuan) is available. It features an imported ESS9038 DAC chip and PCM5101A output mode, Bluetooth 5.0, and supports lossless USB decoding. Compatible file formats include WAV+CUE, WMA+CUE, FLAC+CUE, APE+CUE, MP3, and MP2, with support for FAT16/FAT32 file systems. The unit is controllable via dedicated iOS and Android apps, allowing users to select audio sources (USB/Bluetooth), access local playlists, and choose tracks freely—offering a much more convenient experience than traditional physical buttons for track navigation.
