This DAC costs as much as a flagship smartphone. It plays like stationary equipment

Questyle Sigma Pro is a portable DAC and headphone amplifier that is designed to provide sound quality from high-end stationary systems in a mobile device. At the same time, it will allow you to drive the most demanding audiophile headphones.

The device uses two ESS ES9069Q systems operating in a dual-mono configuration, where each channel is operated by a separate transducer. This improves channel separation and minimizes crosstalk between them.

A special feature of the Sigma Pro model is the CMA (Current Mode Amplification) technology, which distinguishes this DAC from others on the market. Instead of classic voltage amplification, the system works directly on the current signal, which is to ensure a wider bandwidth, faster signal growth and very low distortion – the manufacturer declares THD at the level of 0.0002%.

Sigma Pro reaches a peak power of over 8 W – a value rarely seen in portable devices. At the 4.4 mm output, it offers 1200 mW at 32 Ω and 160 mW at 300 Ω, which allows you to power both sensitive IEMs and demanding planars.

Sigma Pro is distinguished by a set of connectors rarely found in portable devices. There are three formats available for the headphone output: 3.5 mm (unbalanced), 4.4 mm (balanced) and 6.35 mm. The gain switch offers three levels (Low, High, Studio) in headphone mode and two levels in IEM mode.

Digital inputs include USB-C (UAC 2.0), as well as Toslink and coaxial S/PDIF (both up to 192 kHz/24-bit). Bluetooth 5.4 supports SBC, LE Audio, aptX, aptX HD, aptX Adaptive and LDAC codecs, and the device is Snapdragon Sound and Sony LDAC certified. Apple MFi certification guarantees full compatibility with iPhones and iPads.

A unique element are the analog inputs: 3.5 mm and 4.4 mm, enabling the connection of analog sources, e.g. a turntable with a preamplifier or a microphone preamplifier. These inputs also allow recording – the signal is converted to 48 kHz/24-bit and sent via USB to a computer or smartphone, with the possibility of real-time monitoring.

The Sigma Pro housing is made of sandblasted aircraft-grade aluminum. The front and rear panels are protected by Kunlun optical glass with a coating to reduce RF interference. The transparency of the glass reveals the internal components.

Sigma Pro has a total of two USB-C ports: one only for audio transmission, the other for charging. Separating the power supply from the signal eliminates interference and allows you to use the device while charging without burdening the smartphone’s battery. The 4300 mAh battery provides up to 12 hours of operation.

Questyle Sigma Pro is now available for sale in Poland for PLN 3,999. The manufacturer is also introducing the basic Sigma model, which costs PLN 2,699.