Stereocheck Reviews:

Esoteric C-02X: Next generation high-end preamplifier

The Esoteric C-02X stereo preamp represents the next generation of Esoteric’s line of high-end components that deliver audio excellence. It has advanced circuit design and dual mono topology,...

Esoteric C-02X
Esoteric C-02X

The Esoteric C-02X stereo preamp represents the next generation of Esoteric’s line of high-end components that deliver audio excellence. It has advanced circuit design and dual mono topology, which dramatically improves the transmission of all the power and energy of the music. The Esoteric C-02X preamplifiers are hand-assembled individually at the Esoteric factory in Tokyo and utilize the knowledge and technology gained during the development of the flagship Grandioso line. The Esoteric C-02X power supply features a fully independent dual mono design that completely eliminates crosstalk between channels. As many as five power transformers with generous power reserves for each channel block power supply interference, ensuring that the amplified sound is clear and natural. The technologies of the Grandioso line can be found in the careful routing of the power supply circuit boards, which also contribute to the excellent sound quality of the C-02X.


The input signal first goes to a special buffer amplifier, and then the balanced circuit of each of the stages begins. By eliminating common-mode noise and lowering circuit impedance, the amplification circuitry receives a clean, noise-free signal via the shortest possible path, delivering exceptionally high signal-to-noise ratios. The Quad Volume Control System (QVCS) for the Esoteric C-02X uses four precision resistor assemblies that are synchronously switched when the volume knob is rotated. This ensures complete independence of the left and right channels and their inverted paths, as well as the shortest signal paths. The Esoteric C-02X’s front-panel control section is completely isolated, both physically and galvanically, from the main preamplifier module by means of an optocoupler. To avoid interfering with the audio circuitry, this section is disabled when not needed. The power supply contains as many as five power transformers (for the left, right balanced channels and for the control circuit), as well as high-capacity capacitors with low impedance. Silicon carbide (SiC) Schottky diodes are used in the high-speed rectifier circuit to improve resolution and signal-to-noise ratio. Proprietary ESOTERIC-HCLD (High Current-capacity Line Driver) output buffer circuits feature high current carrying capacity and an incredible slew rate of 2,000 V/µs. Next to the output buffer is a bank of EDLC (Electric Double-Layer Capacitor) super-capacitors, originally developed for the top-end Grandioso C1 model.


In a compact size, it features an extraordinary 100,000uF capacitance per channel and delivers high instantaneous power for consistent bass performance. Esoteric C-02X has its own 3D optimized 2-layer chassis with five insulated 2-mm steel sheet compartments, which dramatically reduces the level of vibrations and mutual interference. The lower level of the chassis is made of 5mm steel, and the front panel is made of thick aluminum. Four proprietary ESOTERIC point supports ensure cabinet stability and absence of resonances. The elegant volume control knob and input selector are machined from solid aluminum billets. Like the Grandioso C1, their drive uses VRDS disc drive mechanics with bearings for precise and smooth rotation. The drive force is specifically fine-tuned to give the owner the luxury of analog control when operating this high-end preamp