Audio
Questyle M15i Portable USB DAC & Headphone Amplifier — MFi Certified
Product description
Patented Current Mode Amplification — This compact DAC/amplifier uses Questyle’s Current Mode topology rather than a conventional voltage output stage. The design aims for extremely low distortion and very fast transient response, producing a warm, natural presentation and high fidelity output that is suited to lossless and high-resolution sources.
Wide device compatibility — The unit works with computers, smartphones and tablets. Officially compatible with iOS, HarmonyOS, Android 5.1+ and Windows 10+ systems, it supports plug-and-play operation with many modern devices. If you encounter a compatibility problem, Questyle offers customer support to help resolve connection issues.
Dual headphone outputs — The M15i provides a 3.5mm single-ended output and a 4.4mm balanced output. A manual gain switch lets you reduce hiss with sensitive IEMs or increase drive for power-hungry full-size headphones. The balanced 4.4mm output delivers the greatest dynamics and channel separation.
Flagship ESS DAC and hi-res decoding — Inside sits the ESS ES9281AC DAC chip, with hardware decoding for PCM up to 768kHz/32-bit and DSD512 playback. Streaming services or local high-resolution files will reveal more micro-detail, wider imaging and improved dynamic control compared with basic dongles.
Official MFi certification — The M15i carries MFi approval for seamless connections with recent iPhone models (including iPhone 16/17 series), iPad and Mac devices, helping avoid connection errors and excessive battery drain that can occur with uncertified adapters.
What’s in the box — The package includes: one M15i USB DAC/headphone amplifier, one USB-C to USB-C cable, one USB-C to USB-A adapter, and a user manual. Questyle also provides customer service for setup or troubleshooting questions.
Optional Lightning adapter — For Lightning-only iPhone models, Questyle offers an MFi-certified LTC02 Lightning-to-Type-C adapter sold separately to enable connection without compatibility concerns.
Pros
- Current Mode Amplification for low distortion and quick transients
- Dual 3.5mm and 4.4mm outputs with manual gain control
- Hardware ESS ES9281AC DAC with PCM768k/DSD512 support
Cons
- Supplied USB-C cable can feel stiff and stresses the port
- Balanced output is clearly superior to single-ended
- Some users report intermittent reliability issues
VerdictThe M15i brings desktop-style Current Mode Amplification and an ESS ES9281AC chip into a pocket-sized dongle. It excels with balanced output and handles high-resolution PCM and DSD files with clarity and muscular drive, while offering wide device compatibility and MFi support for iPhone users. Cable quality and occasional reliability concerns are the main negatives, but for critical listeners who
Reviews
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Mark 5/5
Great match for EDM
Works well for electronic music. Paired with TSMR Amor and Eloit Velvet IEMs, it smoothed the highs and tightened the presentation. Solid value for lively, punchy genres.
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Jerry C 5/5
Needs warm-up, then expansive soundstage
Give it roughly ten minutes of playtime and the sound opens up. Some suggest longer burn-in for Class A circuitry. Through the 4.4mm balanced output it produces a lovely, wide soundstage — better headphones reveal more benefit.
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KatH 5/5
Stunning when used balanced
I've used this for months with an iPhone and Grado cans. The two outputs differ a lot — the balanced 4.4mm is where it truly shines. The 3.5mm is acceptable but lacks the imaging and depth of the balanced feed. Once I switched to balanced, I was hooked and listen nonstop.
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kk 5/5
Big upgrade for iPhone 17 listeners
This tiny DAC noticeably improves sound from my iPhone 17 with Hifiman Sundara and Meze Alba. No internal battery to charge and minimal impact on phone battery life. It elevates clarity and dynamics without adding another device to recharge.
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Sou Lee 3/5
Stopped working after a few months
Received mine in March 2026; it failed in August. It appeared as a generic ESS USB Audio device on multiple computers and produced no audio. Website firmware tools didn’t help and there was no clear RMA path, so I bought a second unit to see if it lasts.
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Argamas 4/5
Strong overall sound but cable attachment is weak
Upgraded from an entry-level unit and the audio is excellent with my Focal Azurys and Android player. Bit-perfect playback works fine. However, the supplied USB-C cable is stiff and flexing stresses the soldered connector, causing disconnects while mobile. It’s fine at a desk but problematic on the move, so I purchased a more flexible OTG cable.
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Gary 5/5
Noticeable improvement over cheap dongles
Yes — this external DAC delivers a fuller, richer sound than a basic $10 dongle. Bass and mids are more present, staging and imaging improve. If you’re a critical listener it’s worth considering; casual background listeners may not find the gain worth the upgrade.
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Ink-Stroke 3/5
Interference present
Produced too much interference; I could hear noise in my headphones.
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Susan 5/5
Compact unit with plenty of power
Drives my Focal Clear MG very well. Compared to four other DACs I've tried, this has the necessary power, detailed sound and a spacious presentation. I love it.
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EDVALDO DA SILVA LIMA 5/5
Very happy with my purchase
High-quality product. Extremely satisfied.
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gavin 1/5
Recurring static issues across units
Owned four units. The first had a flaky USB-C connection. The remaining three produced intermittent quiet static/sputtering noises. With an iPhone 14 Plus and a MacBook Air, the M15i sounds excellent, but the persistent noise problems undermine the experience.
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Gilman Wong 5/5
Beautiful sound, but mine failed early
I loved the neutral, clean sound and it drove a range of IEMs and headphones effortlessly—especially from the 4.4mm output. Questyle’s short USB-C→Lightning cable (sold separately) is one of the few that didn’t wiggle in my phone. Unfortunately my unit died on day six and wouldn’t power on; I requested a replacement rather than a refund.
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