The THD UniValve 15W Class A Amplifier Head delivers tones from smooth and clear to warm and full to aggressive overdrive. The single-ended Class A circuit design uses the highest-quality parts and hand-built construction for clean and faultless operation. The UniValve is easily capable of driving a 4x12" cabinet, yet is also small and light. Its built-in Hot Plate Power Attenuator lets you experience the indescribable freedom of wailing away with full output distortion at volume levels that are quiet enough to let your neighbors sleep.