Audio input: Stereo /Record player MM () Audio output: Stereo / 3.5mm headphone jack Earphone impedance range: 16-3000 Earphone output power: 250mW@32 Q 100mW@64 Q 60mW@128 Q : Input level: 0.775V RMS Output level: 1.5V RMS Input impedance: 100K ohms SNR: ≥106db Frequency response: 20HZ-20khz (±0.5dB) Record Player: Input level: 0.005V RMS (MM) / 0.0005V RMS () Output level: 0.6V RMS Input impedance: 47K ohm (MM) / 3300ohm () SNR: 80db Frequency response: Reference RIAA±2dB : ≤0. 1% :≤0. 1% The backlight color is adjustable: green/orange/off Working voltage: DC 12V(≥1A) Colour:black Material:Metal Due to different batches, there may be differences in product appearance and printed text, which not affect use Package Contents: 1 * preamplifier 1 * data cable 2 * E2 tubes 2 * A2 tubes Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.