BADA PH12. (headphone amp) There is plenty on the internet about these. Great headphone amp but is even better If you change the tubes to good NOS tubes. This was my demonstrator and has less than 10 hours use.

Frequency response: 30Hz-30kHz (-0.5dB) Harmonic distortion: <0.08% (1V OUT) SNR:> 86dB Gain: 21dB (AUX IN) Recommended Headphone Impedance: 40-600 (Ohm) Output power (A Class): 300mW (300O) Power Maximum power: <40W Separation:> 55dB (10kHz) Size: Width 180X depth 330X high 150 (mm) Weight: 5.2kg Gross weight: 6.5kg