Cayin Spark C6 WM8741 DAC Portable Headphone Amplifier for Apple iPhon – Extreme Audio
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Khadas Introduces Magnetic Snap-On Ultraslim Hi-Res Headphone Amplifier | audioXpress
ES·PRO AUDIO DSD256 DAC 384Khz 32Bit Headphone Amp DAC For iPhone To 3.5MM #om9 | eBay
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EarMen TR-Amp Portable USB DAC/Amp/Preamp
Maktar Spectra X2 Hi-Res DAC - 3.5mm to Lightning 32-bit DAC Headphone Amp for iPhone/iPad | Reverb