Ampeg PF-20T Bass Head, Electric Bass Head, All-tube amplifier, Power: 20 W @ 4 or 8 Ohm, Preamp tubes: 2x 12AX7, Power amp tubes: 2x 6V6, Controls: Bass, mid and treble, Input gain controls, Preamp balanced line out, Pre/Post EQ, Ground Lift, Transformer balanced line out, Ideal for studio applications as load resistance (speaker) is not required, Adjustable bias controls, Dimensions: 185 x 330 x 264 mm, Weight: 6.9 kg