Questyle CMA 600i: who needs a stack of components when CMA600i does it all so well? DSD256, fantastic clarity, plenty of drive. Heck yes, I want it. – Audio Primate
M12 Mobile Hifi DAC/ amplifier - Questyle
Questyle M12 Portable Headphone Amplifier USB DAC, Hi-Res DAC, Low Noise,for Smartphones, PC, Laptops - 3.5mm Jack - Headphone Amps, USB DAC : Amazon.co.uk: Electronics & Photo
Questyle Audio Gold Stack Reference HeadFI System Review | StereoNET United Kingdom
M12 Mobile Hifi DAC/ amplifier - Questyle
THE QUESTYLE FAMILY TREE - Headphone Guru
Questyle M15i Headphone Amplifier Portable DAC USB DAC Amp with Dual-Jack, Portable Headphone Amp - Apple MFi Certified, Hi-Res DAC - Low Noise, for iOS/Android/PC: Amazon.co.uk: Electronics & Photo
Questyle CMA18 Portable – Elise Audio
Questyle CMA Fifteen Review – Bloom Audio
Questyle Audio QP2R/HB2 portable audio player | Hi-Fi News