This headphone amplifier module is based on the use of an Electro Harmonix 12AU7A/ECC82-EH tube, as well as three MJE15034 transistors and two MOSFET IRF610. The card has two outputs in 6.35mm and 3.5mm jack format. It is also possible to add to the module a 10K potentiometer (not supplied) to allow a volume control. The power supply is made in 40V AC and 6V AC. The power supply stage includes 6 capacitors 63V of 3300µF each.