At the heart of the T201 Audio Motherboard are two meticulously matched U.S. Raytheon JAN6418 military-grade NOS miniature vacuum tubes, selected for their musicality, stability, and long-term reliability.

Tube and Solid-State timbre mode switching is available—allowing each listening mode to reveal its own distinctive sonic character: rich, expressive, and unmistakably analog.

Experience warmth, texture, and emotion—reimagined for modern portable audio.

Based on the inherent characteristics of the JAN6418 miniature vacuum pentode, Cayin’s engineering team implemented a selective local negative feedback topology at the anode stage. By varying the anode connection scheme, the circuit delivers clearly differentiated tuning across key parameters, including frequency response, distortion characteristics, and output impedance.

Via the system UI, users can freely switch between modes, allowing the three timbre options to adapt precisely to different headphones, output configurations, and personal listening preferences.

The classic tube mode offers a warm, rich, presentation with smooth textures. The modern tube mode brings a more open and expansive soundstge and an improved extension at both frequency extremes. The solid-state mode has a fast transient response with an increased dynamic range. The tone is neutral and transparent, with precice control and accuracy.

The JAN6418 vacuum tubes are housed in a custom-designed silicone damping sleeve, assembled as an independent module and integrated with the chassis through a suspended mounting structure. This floating architecture provides multi-directional buffering and vibration absorption, delivering comprehensive mechanical protection against microphonic interference.

At the circuit level, Cayin’s engineers applies further in-depth optimization, introducing inter-stage loop negative feedback to precisely control feedback behavior. A multi-stage, ultra-low-noise regulated power supply is employed to ensure stable filament voltage, screen voltage, and grid bias.

The DAC stage is built around AKM’s flagship AK4497S, featuring the upgraded VELVET SOUND™ architecture. It supports high-resolution audio input up to 768kHz PCM and DSD512, delivering precise and faithful reproduction of every musical detail.

Sharing its design lineage with the AK4499EX, the AK4497S incorporates Data Weighted Averaging routing technology, combined with ultra-low distortion and low-noise design, advanced multi-bit digital filtering,
and a high-performance oversampling architecture. 

The INA1620 features 0.004% precision-matched thin-film resistors for exceptional accuracy, with an integrated EMI filter and an ultra-low noise density of just 2.8 nV/√Hz at 1 kHz.

With two internal amplifier channels operating in parallel, current output capability is significantly increased. This design ensures a fully dynamic performance across the entire volume range, delivering a sound that remains powerful, composed, and fatigue-free—regardless of listening level.