KS-4T-3FT HiFi 2.5mm Balanced Male to 3.5mm Stereo Female Audio Connection Adapter Cable for Astell&Kern AK100II, AK120II, AK240, AK380, AK320, DP-X1, DP-X1A, FIIO X5III, XDP-300R etc.

ONKYO Hi-Res Digital Audio Player DP-X1A

AudioQuest - Dragonfly Cobalt USB DAC/Headphone Amplifier

FiiO M11 Android High Resolution Lossless Music Player with aptX, aptX HD, LDAC HiFi Bluetooth, USB Audio/DAC,DSD256 Support and WiFi Play Full Touch Screen

DL-DH 2.5mm Trrs Balanced Male to 4.4MM Balanced Female Cable, Headphone Audio Adapter for Astell&Kern AK100II, AK120II, AK240, AK380, AK320, DP-X1A, KANN etc. DL-DH

EarStudio ES100-24bit Portable High-Resolution Bluetooth Receiver/USB DAC/Headphone Amp with LDAC, aptX HD, aptX, AAC (3.5mm Unbalanced & 2.5mm Balanced Output)

Astell&Kern A&Norma SR15 Portable High Resolution Audio Player, Dark Gray

FiiO FH7 5-Drive (1DD + 4BAs) Hybrid in-Ear Earphones/Headphones with DIY Sound Filters,High Fidelity for Smartphones/PC/Tablet (Black)

Pioneer hi-res digital audio player XDP-300R (S) (Silver)

FiiO Q1 Mark II Native DSD DAC & Amplifier for iPhone, iPod, iPad and Computers