Questyle M15i | Balanced Portable DAC and Amp

M15i is the MFi Certified Update to Questyle’s Beloved Ultra-portable Powerhouse

• M15i boasts near universal compatibility with any mobile device or computer
• 3.5mm and 4.4mm output with selectable gain, provides higher level of power for a wider range of headphones
• Can handle up to PCM768kHz/32bit and DSD512
• Optimizes power consumption to prevent premature phone battery drainage
• Ultra-low noise floor of -130dB for a pure background and real sound

Technology Without Boundaries

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 (1st Gen M15 supports up to PCM384 and DSD256). Audio distortion performance and output power have also been upgraded compared to the previous generation.

The original M15 was a best seller at Bloom and never actually experienced a slowdown in sales during its lifecycle. With the M15i, Questyle looks to expand its predecessor’s popularity and bring and even higher tier of premium audio enjoyment in a portable form factor.

Hardcore Technological Aesthetics

The design of the Kunlun glass window coupled with the exquisite craftsmanship of the PCD, presents the critical elements of signal processing and technological aesthetics.

Apple MFi Certified for Guaranteed Performance and Compatbility

The “i” in M15i indicates that it has been certified by Apple’s MFi. MFi certification ensures perfect support for iPhone/iPad and seamless integration into the Apple ecosystem. It complies with Apple’s stringent requirements for external devices in terms of power consumption and compatibility, avoiding the risk of damage to phones and systems from arbitrary device pairings.

Patented SiP Current Mode Amplifier

The M15i contains two groundbreaking “current mode” patented 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 hidden details in songs.

As a result, the risk of overheating or interruptions during long listening sessions is extremely low thanks to the patented current mode amplification (TOREX precision power management technology) as well as the M15i’s high performance and low power consumption.

Full Compatibility for True Lossless Enjoyment

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

3.5mm and 4.4mm Dual Ports with Gain Adjustment

The M15i, equipped with (x4) current mode 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, rendering the M15i suitable for a wide range of apps and devices.

Dynamic Sampling Rate Display

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

Specifications

Appearance

• Material: CNC machined aluminum
• Color: Black
• Size: 61.9mm x 27.9mm x 12mm

Compatible Operating Systems

• Android phones and tablets: Android 5.0 and above
• PC: Win10 1803 and above
• Apple cellphone: iOS (You need to buy an OTG cable for Lightning to USB-C)
• Apple computer: Mac OS

DAC Capability

• PCM: 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 Power

• 3.5mm:
• RL=300Ω | Po=11.97mW
• Vout (Max)=1.895Vrms
• 4.4mm:
• RL=300Ω | Po=22.6mW
• Vout (Max)=2.624Vrms

Frequency Response & THD

• Frequency Response: ±0.1dB (20Hz-20kHz) | ±2dB (20Hz-80kHz)
• THD+N: 0.0003%
• DAC: ESS flagship USB DAC chip ES9281AC

In the Box

• M15i Mobile Headphone Amplifier with DAC
• USB Type-C to Type-C Cable
• USB Type-C to Type-A Cable
• Warranty Card
• User Manual