The HA243 is a high powered headphone amplifier with four 1/4 and 1/8 (3.5mm) headphone outs. The HA243 features an A-B switch for each channel to monitor either the A or B input with the flick of a switch! 4: 1/4 TRS Headphone Outputs with Level Control. With the new JRC3414 I.C.s it has plenty of gain. 1/4 3.5mm and RCA A and B Inputs. Switchable mono or stereo for both A and B inputs. Specifications: Input Impedance: 10 K Ohms. Maximum Input Level: +26 dBV. Max Gain: 20 dB per channel. Output Power: 326 mW per side 652 mW per channel (@ 62 Ohms). S/N Ratio: 92 dB. THD: <.008%. Power: 15 VDC (Adapter included). Size: 6.75 x 1.75 x 4.75.