Vox NT15H Night Train 15-Watt All-Tube Guitar Amplifier Head Rock-solid, all-tube head that is made to travel. Uncompromising sound with two 12AX7 preamp tubes and two EL84 power tubes. Selectable BRIGHT or THICK mode switch provides EQ and Gain variations for just the right tone. Dual-power tube mode offers 15 watt (Pentode Power) or 7.5 Watt (Triode Tone) operation. Master Volume control preserves your gain settings at any playing level.