Delivery time approx. 2 weeks

A new generation of mobile HiFi listening pleasure  

• Presentation at CES 2024: Questyle introduced the M15i, a second-generation mobile dongle DAC, at the Consumer Electronics Show 2024.

• The shift to the mainstream: In today’s 5G era, users place extremely high value on the portability of smart devices. As more music streaming apps offer lossless audio formats, mobile high-resolution audio has long since entered the mainstream.

• The portable solution: Traditional HiFi audio products are difficult to use daily with smartphones due to their enormous size and high power consumption. The M15i combines Questyle’s technological achievements from the past decade in a compact housing. It enables audiophiles to enjoy lossless music anytime and anywhere and harmonizes perfectly with classic HiFi headphones.

Physical Tuning – Experience authentic sound texture and depth layering

• True Physical Tuning: The M15i Special Edition relies on a purely physical tuning approach. We avoid simple frequency corrections via software equalizers. Instead, we focus on the targeted selection of component materials, precise structural tuning, and long-term system optimization to refine the listening experience on a purely perceptible level. This tuning enhances subjective sound qualities such as texture, depth layering, density, and spatial imaging without altering conventional, objective audio measurements.

Blues Blue (Blues Blue)

• Color Inspiration: Inspired by the atmosphere of nighttime jazz clubs.

• Custom Tuning: Specifically tailored for Jazz & Blues.

• Sound Character: Delivers warm sound stages and genuine live atmosphere (optimized for noticeable warmth in the midrange and harmonic details in the high frequencies).

Electro Purple (Electro Violet)

• Color Inspiration: Inspired by neon-lit EDM parties.

• Custom Tuning: Specifically tailored for EDM & ACG (Anime, Comic and Games).

• Sound character: Captures energetic rhythms and immersive depth (optimized for extremely fast attack behavior / transient resonance).

Apple MFi certification

• Guaranteed compatibility: The “i” in the name M15i stands for official certification through Apple’s MFi program.

• Perfect interaction: The certification guarantees smooth compatibility with iPhone, iPad, and the entire Apple ecosystem.

• Safety in focus: The device meets Apple’s strict requirements regarding power consumption and system compatibility. This minimizes the risk of damage to the smartphone or operating system caused by arbitrary USB connections.

Wide system compatibility

Questyle Labs has extensively optimized and tested the M15i for compatibility with common smartphones, tablets, and PCs:

• Mobile operating systems: Full support for iOS, HarmonyOS, and Android (version 5.1 and higher).

• PC & Mac: Driverless operation (plug and play) on Windows 10 (version 18.3 and higher) as well as on macOS.

• Streaming platforms: Compatible with popular services like Spotify, TIDAL, QQMusic, and Apple Music.

Patented amplifier technology & power management

• Current mode amplification: The M15i uses two groundbreaking, Questyle-patented SiP modules that operate in current mode. A total of four of these amplifier engines are used.

• Outstanding measurements: Due to the low impedance of the power circuit, the system achieves an enormous bandwidth of up to 1 MHz and an extremely low distortion of only 0.0003%. This makes even the tiniest, hidden details in the audio tracks audible.

• No overheating: Thanks to efficient amplifier technology combined with a precision power management system from TOREX, the M15i operates extremely energy-efficiently. The risk of overheating or connection interruptions during long listening sessions is minimal.

• Patent notice: Global PCT patent no. US 9,614,483 B2.

Connections and gain adjustment

• Dual-port design: The M15i features both a 3.5 mm jack connector (Single-Ended) as well as via a 4.4 mm jack connector (fully balanced).

• Manual gain adjustment: The gain can be manually adjusted via a physical switch (High Gain / Low Gain). This allows flexible tuning to the sensitivity of the headphones or audio system.

Ultra-low noise floor

• Pure sound: Just as a deep black background makes colors shine more intensely, only an extremely low noise floor reveals the finest details in music.

• Measurement results: In Questyle’s test environments (measured with Audio Precision AP2722), the M15i achieves a noise level below -130 dB in one measurement

Status and LED indicators

The device features smart indicators to show the current operating status:

• Data and sampling rate indicator:

  • 1 red LED: PCM data with a sampling rate up to 48 kHz.

  • 2 red LEDs: High-sampling-rate PCM data (over 48 kHz) or DSD audio data.

• Gain indicator:

  • H (High Gain): Both LEDs light up.

  • L (Low Gain): Only one LED lights up.

Partnership with ESS Technology

• Global collaboration: Questyle works closely with the research teams of ESS in the USA, China, and Canada.

• Flagship chip: The heart of the updated ESS flagship DAC chip beats in the M15i ES9281AC. It supports digital-to-analog conversion up to PCM 768 kHz and DSD512 (for comparison: the previous M15 model supported up to PCM 384 kHz and DSD256). Output power and distortion values have also been noticeably improved compared to the previous generation.

Technical data 

Scope of delivery 

• Questyle M15i Mobile Headphone Amplifier with DAC

• Type-C to Type-C cable

• Type-C to USB-A cable

• Warranty card

• User manual  

Optional leather case

Optional accessories: For connection to older Apple devices with Lightning port, the officially MFi-certified adapter Questyle LTC02 (Lightning to Type-C) sold separately.