Apple MFI Certification Ensures High Performance and Compatibility

"i" in M15i indicates that it has been certified by Apple's MFi program. MFi certification ensures perfect compatibility with the iPhone/iPad and the Apple ecosystem. It meets Apple's strict requirements for external devices in terms of power consumption and compatibility, avoiding the risk of damage to phones and systems caused by arbitrary connections of USB devices.

Equipped with Dual Current Mode Patent Amplification Modules, Ultra-Large Dynamics, Capable of Working at High Volume for Extended Periods Without Interruption

The M15i contains two groundbreaking "current mode" patent amplification SiP modules developed by Questyle Technology. Overall, it totals four current mode amplification engines, delivering powerful and clear sound. Given that it operates in the current domain, the low impedance characteristics of the current-mode circuit result in a bandwidth of up to 1MHz and distortion as low as 0.0003%, capturing details hidden in the soundtracks. (as an option This development makes it possible to discern even a tiny detail when listening to music.)
As a result, the risk of overheating or interruptions during long listening sessions is extremely low thanks to the patented current mode amplification, TOREX 's efficient power management system, as well as the M15i's high performance and low power consumption.

• Ultra-Low Distortion: 0.0003%
• Current Mode Amplifiers: 4

Ultra-Low Noise Floor, Pure Background, Enjoy Real Sound Anytime, Anywhere

Just as a pure black background can highlight the richness of colors, only a low enough noise floor can capture the details in the soundtracks, appreciating true high-fidelity. The high resolution of the M15i contributes to a lower noise floor, achieving an ultra-low noise floor of -130dB in the Questyle Lab's testing environment.

Full Compatibility for True Lossless Enjoyment

During the development, Questyle Labs conducted extensive testing and targeted optimization of M15i's compatibility with mainstream smartphones and tablets. Developers managed to achieve high compatibility with iOS, HarmonyOS, Android versions 5.1, etc. As for PC, it supports Windows 10 version 18.3 and above (driver-free) as well as Mac OS systems. Hence, all Hi-Fi headphone users can enjoy lossless audio on streaming platforms anytime, anywhere.

Supporting Dynamic Sampling Rate Display,
High Resolution, True Lossless, No Pygmalion Effect.

Gain Indicator Light

• H high gain (dual lights)
• L low gain (single lamp)

When playing music, the data status indicator will light up.

• A single red indicator means PCM data with a sampling rate not exceeding 48kHz.
• Dual red indicators represent high-sampling-rate PCM data or DSD audio data.

3.5mm and 4.4mm Dual Ports, Manual Gain Adjustment Adaptable to More Headphones and Devices

The M15i, equipped with four current mode amplification engines, supports 3.5mm single-ended and 4.4mm fully balanced output modes. It also features manual gain adjustment, allowing users to choose the gain mode according to personal preferences, headphone characteristics, or the audio system, making it suitable for a wide range of apps and devices.

Equipped with Dual Current Mode Patent Amplification Modules, Ultra-Large Dynamics, Capable of Working at High Volume for Extended Periods Without Interruption

The M15i contains two groundbreaking "current mode" patent amplification SiP modules developed by Questyle Technology. Overall, it totals four current mode amplification engines, delivering powerful and clear sound. Given that it operates in the current domain, the low impedance characteristics of the current-mode circuit result in a bandwidth of up to 1MHz and distortion as low as 0.0003%, capturing details hidden in the soundtracks. ( as an option This development makes it possible to discern even a tiny detail when listening to music.)
As a result, the risk of overheating or interruptions during long listening sessions is extremely low thanks to the patented current mode amplification, TOREX 's efficient power management system, as well as the M15i's high performance and low-power consumption.

• Ultra-Low Distortion: 0.0003%
• Current Mode Amplifiers: 4 Groups

Technology Knows No Boundaries, ESS Flagship USB DAC Jointly Developed

Questyle and ESS along with research teams in the United States, China, and Canada, maintain a continuous and fruitful collaboration to exceed customer expectations in mobile decoding headphone amplifiers. The M15i uses the updated ESS flagship USB DAC chip ES9281AC, supporting D/A converting up to PCM768 and DSD512 (M15 supports up to PCM384 and DSD256). Audio distortion performance and output power have also been upgraded compared to the previous generation.

IN THE BOX

• M15i
• Type-C to Type-C Cable
• Type-C to USB-A Cable
• Warranty Card
• User Manual

SPECIFICATIONS

Compatible Operating Systems

• Android Phones and Tablets: Supports devices running Android 5.0 and above
• PC Systems: Compatible with devices running Windows 10 version 1803 and above Apple Phones: Supports iOS systems
• (Requires additional purchase of the Questyle LTC02 Lightning to Type-C adapter when connecting to devices with a Lightning interface.)
• Apple Computers: Compatible with macOS systems

D/A converting

• PCM: 44.1kHz - 768kHz (16/24/32Bit)
• DSD: DSD64(1Bit 2.8MHz), DSD128(1Bit 5.6MHz), DSD256(1Bit 11.2MHz) DSD512(1Bit 22.4MHz)

Output Interfaces

• 3.5mm single-ended headphone jack
• 4.4mm balanced headphone jack

Output

• 3.5mm: RL=3000, Po=11.97mW, Vout(Max)=1.895Vrms, THD+N=0.0003%
• 4.4mm: RL=3000,Po=22.60mW, Vout(Max)=2.624Vrms, THD+N=0.0003%
• Frequency Response: ±0.1dB (20Hz-20kHz); ±2dB (20Hz - 80kHz) - THD + N: 0.0003%
• DAC: ESS Flagship USB DAC Chip ES9281AC
• Exterior Material: CNC Anodized Aluminum Alloy
• Color: Black
• Dimensions: 61.9[L] X 27.9[W] X 12[D](mm)