Delivery time approx. 2 weeks

The SIGMA Pro is our flagship among portable DAC/amps, developed from Questyle’s pursuit of audiophile perfection. It sets technological standards and proves that performance and portability can coexist to provide a true experience as “portable professional audio equipment”.

• Desktop class: The SIGMA Pro offers desktop-level specifications and sound quality.

• High-quality components: Equipped with four sets of Questyle patented, fully discrete current-mode analog amplifier stages, a dual-mono ESS ES9069 DAC array, and an XMOS XU316 USB interface.

• Master decoding: Supports PCM 768 kHz / DSD512 decoding as well as full MQA unfolding.

• Elegant design: The robust housing is made of sandblasted aerospace aluminum and Kunlun glass.
  
  

Design and dimensions

Functionality meets aesthetics

Guided by the Bauhaus philosophy “Less is more,” the SIGMA Pro impresses with classic industrial design featuring clean lines and geometric shapes, where every detail serves a precise purpose. The transparent design reveals the carefully arranged circuits and chips inside, combining vintage charm with modern technology.

Maximum portability

Built for professional use in various scenarios:

• Size: Similarly compact to an iPhone 16 Pro Max ($(155.7 \times 85\text{ mm})$).

• Weight: Only 330.8 g for desktop performance in a lightweight format.
  
  

Audio performance & technology

Patented current-mode amplifier & TTA architecture

The four sets of patented amplifiers resolve the conflict between compact size, high power, and audio performance:

• Effortless drive for demanding, high-impedance headphones.

• Precise control for low-impedance in-ear monitors (IEMs) for pure, detailed sound.

• Peak output voltage: 25 Vp-p

• Peak output current: 5 A

• Peak output power: >8 W

• THD (total harmonic distortion): 0,0002 %

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

ESS flagship stereo DAC in dual-mono operation

By combining two ESS ES9069 DAC chips in a dual-mono configuration with Questyle’s three-tier TTA decoding architecture (Three-Tier Architecture), desktop-level conversion performance is achieved.

Connections and operation

Front (outputs & control)

• Headphone outputs: 3.5 mm standard, 4.4 mm balanced (BAL), and 6.35 mm standard.

• Display: Display of current settings such as sample rate, decoding format, battery level, and input/output.

• Buttons:

  • SOURCE: Source switching (USB / Bluetooth / OPT / S/PDIF / SE Analog / BAL Analog).

  • GAIN: Three-level gain setting (Studio / High / Low).

  • OUTPUT: Output switching (Line Out / HP Out / IEM Mode).

  • POWER: Power switch.

• Volume control: 360-degree rotary encoder (rotate for volume, press for mute).

Rear (inputs)

• Digital inputs: SPDIF coaxial, OPT optical and Type-C USB (UAC 2.0).

• Analog inputs: 4.4 mm balanced stereo input and 3.5 mm single-ended stereo input.

• Charging port: Separate USB-C charging port (5V/2A), supports charging while listening.
  
  

Features & functions

Professional stereo recording function

The SIGMA Pro allows recording of analog signals (e.g., from turntables or mixers) via the analog inputs while simultaneously monitoring losslessly (synchronous monitoring). After connecting to a host device (smartphone, tablet or PC), the DAC acts as a high-quality external stereo recording system and replaces the device’s internal microphone – without any special software requirements.

Smart battery system

• Battery life: Up to 12 hours on a single charge.

• Two USB-C ports: Separation of data transmission and power supply. The audio port transmits data only while power is supplied by its own battery. In Bluetooth mode, only the battery is used to preserve the smartphone’s battery.

• Battery specifications: Rechargeable lithium-ion battery with 4300 mAh / 3.7 V (15.91 Wh).

Premium wireless audio quality

• Certified for Qualcomm Snapdragon Sound and Sony LDAC.

• Equipped with Bluetooth version 5.4.

• Supports Qualcomm aptX Adaptive (offers CD quality with 16-bit/44.1 kHz lossless as well as 24-bit/48 kHz and 24-bit/96 kHz high-definition audio) as well as aptX HD, SBC and LE Audio.

Comprehensive compatibility

• Apple MFi certified: Guaranteed seamless support and stability in the Apple ecosystem (iPhone/iPad).

• Plug-and-play: Driver-free on iOS, HarmonyOS, Android (from version 5.1), macOS as well as Windows 10 (version 1803 or newer) and Windows 11.
  
  

Technical specifications 

Packaging & accessories

• Questyle SIGMA Pro

• Type-C to Type-C cable (120 cm)

• Type-A to Type-C adapter

• Warranty card & user manual

(Optional protective cases available separately: Standard Edition in Black or Alcantara Special Edition in Blue).