The Questyle M18i Max is a portable USB and Bluetooth DAC/headphone amp built on two ESS ES9219Q chips with current-mode amplification, 3.5mm single-ended and 4.4mm balanced outputs, and an 1800mAh battery rated up to 12 hours on Bluetooth. It suits IEM and headphone listeners who want one box for wired USB playback and LDAC or aptX Adaptive Bluetooth from a phone.
Who the Questyle M18i Max is for
iPhone, Android and computer listening: Apple MFi certification and a 16-core XMOS XU316 USB controller let it work as a driver-free USB DAC with iPhone, iPad, Android phones, Macs and Windows 10 PCs.
Wireless listening from your phone: Bluetooth 5.4 with Snapdragon Sound and LDAC certification supports AAC, SBC, aptX, aptX HD, aptX Adaptive, LDAC at 24-bit/96kHz and LE Audio, so the phone can stay in a pocket.
Balanced IEMs and harder-to-drive headphones: It has 3.5mm single-ended and 4.4mm balanced jacks, two gain settings and four current-mode amplifier circuits with 1.5A peak output current; Questyle says it can drive everything from IEMs to high-impedance and planar headphones.
Long days away from a charger: The 1800mAh battery is rated for 12 hours over Bluetooth or 7 hours as a USB DAC, and a separate USB-C charging port lets you charge while you listen.
Calls and desk setups: A built-in Infineon microphone with Qualcomm cVc 8.0 handles hands-free calls, and Questyle notes it can feed powered speakers through 3.5mm-to-RCA or 4.4mm-to-XLR cables (not included).
Skip it if: you want a stick-sized dongle or need files beyond PCM 384kHz and DSD256 — the M18i Max is an 86 × 55 × 15mm unit with its own battery, and Lightning iPhones need Questyle's LTC02 Lightning to USB-C cable, sold separately.
Questyle M18i Max key specs
DAC: Dual ESS ES9219Q in a dual-mono layout with Questyle TTA three-tier decoding
USB input: USB-C with XMOS XU316; PCM 44.1–384kHz (16/24/32-bit), DSD64/128/256
Bluetooth: 5.4, Snapdragon Sound and LDAC certified; AAC, SBC, aptX, aptX HD, aptX Adaptive, LDAC (24-bit/96kHz), LE Audio
Outputs: 3.5mm single-ended, 4.4mm balanced
Amplifier: Two SiP modules with four current-mode circuits; 1.5A peak output current; High and Standard gain
Measurements: THD+N 0.0002%; frequency response ±0.1dB (20Hz–20kHz), ±2dB (20Hz–80kHz)
Battery: 1800mAh; up to 12 h on Bluetooth, 7 h as a USB DAC; separate USB-C charging port
Display and build: OLED display; CNC-machined anodized aluminum in Tech Black; 86 × 55 × 15mm
Compatibility: iOS and iPadOS (Apple MFi), Android, macOS, Windows 10; Lightning devices need the LTC02 cable (sold separately)
In the box: M18i Max, USB-C to USB-C cable, USB-C to USB-A adapter, user manual
Genuine Questyle stock. Free shipping on every order, 45-day returns.
Questyle M18i Max vs similar options
vs Questyle M18i: Costs less and also takes wired USB and Bluetooth input with current-mode amplification; pick the M18i Max for its 1800mAh battery, rated 12 h on Bluetooth and 7 h as a USB DAC.
vs Questyle SIGMA: Adds PCM up to 768kHz, DSD512 and a 4300mAh battery; pick the M18i Max if PCM 384kHz and DSD256 cover your files and you want to spend less.
Yes. Every unit we sell is genuine and brand-new, shipped in its original packaging, and backed by our 1-year TonePier warranty and 45-day returns.
Where does my order ship from, and how long does it take?
Every order ships from our warehouse in China, with full tracking, and most orders ship within 3 business days. Shipping is free on every order; most US orders arrive within 7–15 business days and most orders to other countries within 7–20 business days — see our shipping policy for details.
What if it isn't for me?
You get 45 days to decide. Keep the packaging, keep it in like-new condition, and send it back for a refund. Ear tips unsealed for hygiene reasons are fine — we expect you to actually listen.
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