d&b A1 Mainframe with two power amplifiers Maximum output power 1200 W and 350 W into 4 Ohms d&b audiotechnik A1 mainframe houses in a 3 rack unit high, 19″ rack mount enclosure. The A1 incorporates: two power amplifiers (1200 W and 400 W), softstart power supplies, monitoring and protection circuits with the associated display elements and all connectors. All functions enable remote interrogation and alteration via the d&b Remote Interface Bridge (RIB). The mainframe accepts a single exchangeable controller module. Such module determines both the type and number of loudspeakers which d&b A1 can drive. d&b SenseDrive electronics maintain maximum damping factor with complex loads. It also improves low frequency transient performance when using long speaker cables. The d&b A1 amplifier has a comprehensive protection against overheating and connection to inappropriate or faulty loads. It has a high peak output current capability and a low feedback internal gain structure. Speaker ID protects wrongly connected speakers from possible damage. The A1 is also available as a dual voltage (115 V / 230 V) autosensing version.