Our favorite Bluetooth dongle maker just unveiled the hi-res DAC of our dreams

• Wide headphone support plus aptX lossless and LDAC
• Can record analog sources to external storage and PCs
• $899 (so around £675 or AU$1,352)

Questyle is the firm behind the brilliant little QCC Dongle Pro, which is a superb audio upgrade for smartphones: it's a tiny transmitter that adds all the key hi-res and lossless codecs to phones, tablets, gaming handhelds and more. And now Questyle has launched a bigger and much more powerful device, the Sigma Pro portable DAC and headphone amp.

The Sigma Pro is a new version of the firm's flagship DAC, and it promises desktop-class specs and sound quality from the smartphone-sized device. It may be small but it packs four sets of amplifier stages, a dual-mono ESS ES9069 DAC array and a USB interface with support for PCM 768kHz/DSD512 and full MQA unfolding.

Questyle Sigma Pro: key features and pricing

The outside of the Sigma Pro is made from sandblasted aluminium and Kunlun glass, and in a nice touch the majority of the front is transparent so you can see its electronic innards.

The Sigma Pro features dual USB-C ports that enable you to recharge the Sigma Pro while listening to it, and you can expect up to 12 hours of playback in battery mode. There are 3.5mm single-ended, 6.35mm and 4.4mm balanced outputs, SPDIF and optical digital inputs and both 3.5mm and 4.4mm balanced stereo inputs.

Bluetooth is 5.4 with LE Audio, Snapdragon Sound, LDAC, aptX Adaptive and aptX HD lossless audio at up to 24-bit/96kHz quality. Specs to compete with the best headphones DACs we've tested then? You betcha.

The discrete, fully balanced current mode amplifier has a peak output power of 8W, and Questyle promises ultra-low loaded distortion and "exceptional" noise floor control.

One of the interesting features of the Sigma Pro is its recording support. You can connect its 3.5mm or 4.4mm inputs to analogue audio equipment and then turn that audio into a digital file for external storage or to a PC or Mac.

The Sigma Pro has a recommended selling price of $899 (about £675 / AU$1,351) and it's available in the US directly from Questyle, from hi-fi retailers and from Amazon. There's also a more affordable model with a different DAC setup, the $599 Sigma.

The best headphone DACs for all budgets

➡️ Read our full guide to the best headphone DACs
1. Best budget USB-C portable DAC:
iFi GO Link Max
2. Best budget desktop DAC:
iFi Uno
3. Best premium portable DAC:
iFi xDSD Gryphon
4. Best wireless DAC:
Fiio BTR17

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