BUGERA VALVE BASS AMPLIFIER BVP5500 Powerful 550-Watt valve bass amplifier head for classic sound and performance 4 x 12AX7 valves give you the ultimate sound and feel only valves can provide Valve Gain controls the dynamics and tonal response of the power amp to deliver anything from punchy to thick and compressed sounds Ultra-musical 9-band graphic EQ for total frequency control Dedicated Bass, Mid, Treble and additional Mid frequency control enable ultimate sound shaping