Two and four channel amplifiers for 100V, 70V and 4 Ωsound system lines. Switching power supply, input gain control, 100 V amplifiers with a selectable output power configuration. Fan cooling system, Phoenix output connectors, dual or single input mode, output configuration selector, HP filter, phoenix output connectors. Fan powered cooling balanced XLR input and link output connectors with ground lift; 24V DC power supply. These amplifiers are system, rack mount. The iA amplifiers are made for operation under hard conditions and require minimum maintenance designed to work under hard conditions and require the minimum maintenance after installation.  These amplifiers are used in a medium and large public address and voice evacuation systems.