Cayin R202 Replaceable Audio Motherboard Module for Cayin N6iii

Fully Discrete Fully Balanced Dual DAC Architecture

Incorporates 320 ultra-precision thin-film resistors rated at 0.1% (1/1000) accuracy.

Discrete R-2R PCM DAC is built with 192 pieces of 0.1% high-precision thin-film resistors in a balanced 24-bit DAC configuration, supporting native PCM decoding up to 384kHz.

Discrete 1-Bit DSD DAC is built with 128 pieces of 0.1% high-precision thin-film resistors in a balanced 1-bit DAC architecture, supporting native DSD256 decoding.

Dual Digital Audio Processor: Equipped with powerful algorithmic processing, the R202 supports decoding up to PCM 768kHz and DSD512, with sample rate and format conversion.

Triple Decoding Modes: Auto, R-2R and 1-Bit

Auto Mode – Intelligent Format Matching. In Auto Mode, the system intelligently selects the optimal DAC architecture based on the source format—PCM signals are decoded by the R-2R DAC, while DSD signals are processed by the 1-Bit DAC. This seamless switching ensures each decoding performs at its peak, delivering authentic, true-to-source sound reproduction that preserves the full character and nuance of the original recording.

R-2R Mode: Delivers a rich, smooth, and emotionally engaging sound with an expansive, relaxed presentation.

1-Bit Mode: Offers a more natural rendering of high-frequency overtones, with a clear soundstage and precise imaging.

Quad-Channel Fully Balanced Headphone Amplifier Circuit

Built on a fully balanced DAC architecture, the amplifier section uses six pieces OPA1612 and OPA1662 operational amplifiers to form a fully symmetrical differential signal chain.

Four INA1620 op-amps forms the quad-channel balanced headphone amplifier, with dual internal channels paralleled per chip and four-chip balanced drive. This enables full differential amplification of analog audio signals, ensuring precise detail reproduction and exceptional dynamic response.

Matrix-Structured Clean Power Supply Design

The headphone amplifier is powered by an LT8582-based high-performance dual-polarity boost supply, delivering ultra-clean power with microvolt-level ripple suppression through LC filtering — significantly enhancing dynamic load response.

The DAC and op-amps are powered by a matrix formed from TPS61087 and TPS61240 converters, followed by 7 ultra-low-noise LDOs that independently power the digital, analog, and clock sections. This minimizes noise density and lays a robust foundation for high-fidelity audio output.

Quad-Channel Precision Analog Volume Control

Utilizes the JRC NJW1195 full-balanced volume control chip, offering 256-step adjustments in 0.5dB increments. Through rigorous parameter analysis and acoustic matching, 100 core levels are carefully selected to ensure low distortion and excellent channel balance throughout the adjustment range — delivering pure sound quality with precise and efficient volume control.

Phone Output Only: Pure and Purposeful

Within the limited PCB space, a dedicated audio circuit architecture is meticulously optimized for direct load-driving using fully balanced signal transmission and
amplification. The R202 features a PO (Phone Out) output only, with no LO (Line Out) function — a design choice made to maintain purity and focus in audio output performance.