◯ This is a listing for the TEAC HA-501. ◯ I purchased this used in June of this year. It powers on and plays back audio without issue. ◯ I bought this because it's a genuine TEAC headphone amplifier. It lives up to its reputation as a reference for the beyerdynamic T1 1st generation headphones, and its compatibility with the T1 is outstanding. It excels at outputting the sound created by the upstream equipment directly to the headphones without embellishment, producing "clean" music. Although it's a headphone amplifier from a while back, I believe it's still a great piece of equipment that holds its own today. ◯ The only included accessory is the power cable. The box, instruction manual, etc., are not included. ◯ When purchasing, please understand that this is a used item stored by a private individual, and I ask for no returns or exchanges. Manufacturer: TEAC Model Number: HA-501 Country of Manufacture: CHINA Inputs: XLR IN 1 system Connector XLR-3-31 (1: GND, 2: HOT, 3: COLD) Input impedance 20kΩ Input sensitivity 2Vrms LINE IN 2 systems (LINE1, LINE2) Connector RCA Input impedance 10kΩ Input sensitivity 1Vrms AUX IN 1 system Connector 3.5mm stereo mini jack Input impedance 13kΩ Input sensitivity 0.5Vrms Outputs: HEADPHONE OUT: Connector Stereo standard jack Suitable load impedance 16Ω～600Ω Maximum practical output: 32Ω load 1400mW + 1400mW 600Ω load 135mW + 135mW Rated output: 32Ω load 600mW + 600mW 600Ω load 34mW + 34mW Total harmonic distortion 0.01% (1V input, 600mW, 32Ω load) 0.002% (1V input, 1V output, 32Ω load) S/N ratio 110dB (A-Weight, RCA input 2Vrms, 1kHz) Frequency response 2Hz～100kHz (+0dB/-3dB) / 10Hz～100kHz (±3dB) LINE OUT: Connector RCA Output impedance 100Ω Reference output voltage level 316mV Power supply: AC100V, 50-60Hz Power consumption: 22W Maximum external dimensions/weight: 290 (W) x 81.2 (H) x 244 (D) mm (including protrusions), 4.1kg Thank you for looking.