JDSLABS cMoyBB v2.03 Headphone Amplifier Headphone Amplifier Normal model JDS LABS genuine domestic / 1 year warranty (japan import) Alps RK097 Volume Control and On/Off Switch Bass Boost Toggle Switch/ DC Auxiliary Power Jack/ Decoupling Capacitors on All IC Supply Pins Texas Instruments OPA2227 Opamp in Gold-Plated DIP Socket Automatic On/Off (senses headphone cord)/ Custom 2-Layer PCB: Compact Layout with Ground Plane Texas Instruments TLE2426 Precision Virtual Ground (2x optional)