The Sigma DAC/Amp Embodies Questyle's Endless Pursuit of Audio Excellence and Innovation

• AKM AK4493 DAC
• Features Questyle's TTA decoding architecture 
  
• Equipped with latest generation of Qualcomm Snapdragon technology
• Supports dedicated IEM mode

Sigma

Sigma was born from Questyle's uncompromising pursuit of excellence, featuring an innovative decoding architecture and supporting up to PCM768 and DSD512 decoding capabilities. The patented CMA technology combined with a fully-discrete, fully balanced design delivers professional-grade performance in a portable form factor. 

Retro-Inspired LED Accents

The Sigma features a precision-crafted chassis that embodies both aesthetic refinement and technical excellence. Its CNC-machined, ultra-fine sandblasted aerospace aluminum body is paired with custom optical-grade transparent glass, creating a striking visual contrast. Gradient dot-matrix detailing adds depth and sophistication, while the RF signal suppression coating ensures clean, stable performance.

Patented Current Mode Amplifier

Sigma incorporates four sets of patented, fully discrete, fully balanced CMA headphone/output amplifiers. Balancing size, power consumption, and sonic performance is the core challenge in portable audio devices. Questyle's patented Current Mode Amplifier achieves both powerful drive capability and refined sonic character. The fully discrete CMA delivers peak power up to >5W, peak current up to 3A, enabling exceptional dynamic drive capability. 

Desktop-Level Performance

To exceed customer expectations for decoding performance, Sigma uses the highly acclaimed AK4493 DAC from AKM. Additionally, it is engineered with Questyle's TTA architecture to deliver desktop-class audio performance. 

Just as only a pure black background reveals the richness of colors, only a sufficiently low noise floor allows the capture of sonic details, enabling true Hi-Fi audio. Sigma's high resolution grants it an ultra-low noise floor, achieving -130dB in Questyle's lab test environment. 

Comprehensive Compatibility

Sigma supports high-speed USB connections with smartphones and PCs, as well as lossless Bluetooth audio. Output modes can be switched between headphone amplifier and line-out for professional monitors or Hi-Fi systems. It can also enhance PC audio quality in settlings like live concerts. Questyle Lab conducted extensive compatibility testing, ensuring full compatibility with iOS, HarmonyOS, and Android 5.1+. For PC, it supports Windows 10 1803+ (driverless) and macOS. 

Apple MFi Certification

Sigma is officially MFi-certified by Apple, ensuring flawless compatibility with iPhone, iPad, and the broader Apple ecosystem. This certification reflects full compliance with Apple’s strict standards for power efficiency and external device performance, while safeguarding against potential risks posed by uncertified USB accessories. 

Qualcomm Snapdragon and LDAC Certification

Sigma integrates Qualcomm’s latest-generation Snapdragon Sound™ platform with Bluetooth 5.4, earning full certification for both Snapdragon Sound and Sony LDAC. Leveraging Qualcomm’s advanced aptX Adaptive technology, Snapdragon Sound enables support for aptX HD lossless audio, delivering CD-quality 16-bit/44.1kHz lossless streaming and high-resolution 24-bit/48kHz–96kHz audio over Bluetooth.

Additional Features

3.5mm + 4.4mm Outputs
Sigma features both 3.5mm SE and 4.4mm BAL outputs. Combined with manual gain selection and output mode settings, it perfectly drives sensitive IEMs, high-impedance headphones, and Hi-Fi audio systems. 

IEM Signal Processing Path
Sigma supports a dedicated IEM mode. In this mode, the signal path is minimized, and ultra-fine 64-step volume control is enabled. This ensures an optimal listening experience with sensitive in-ear monitors. 

Dual USB-C Ports
Dual USB-C ports allow the separation of data transfer and charging/power.

Professional-Grade Monitoring
Using a 3.5mm-to-RCA or 4.4mm-to-XLR balanced cable, music professionals can use Sigma anywhere as a high-quality interface. Connect mobile devices, PCs, or desktops to Hi-Fi equipment. 

Specifications

• USB Playback
  • PCM up to 768kHz/32bit
  • DSD Native: DSD64, DSD128, DSD256, DSD512
  • DSD Dop: DSD64, DSD128, DSD256
  • UAC 2.0 supported
  • Compatible with WinXP/Vista/Win7/Win8/Win10/Win11/
    Linux/Android/HarmonyOS/macOS and iOS
• Bluetooth Decoding: SBC / LE Audio / aptX / aptx HD/ LDAC
• Headphone Max. Output Power: >1200mW @32ohms balanced
• THD+N: 0.0002% @300ohms
• SNR: 120dB
• Playback Battery Life: 12hrs
• Max Charging Current: 2A
• Charging Time: -3.5hrs

In the Box

• Questyle Sigma DAC/Amp
• Type-C to C 12cm cable
• Type-C to C 120cm cable
• USB-A to Type-C adapter
• Warranty card + user manual