The RH-AUDIO USB/BT Portable Amplifiers are designed with overall 70/100-volt and 4/8 ohms(O) loads and featured an industry leading 5 zoned 100 volt load solution. A variety of audio source options have been engineered into these amplifiers including MP3 player of connecting external USB drive,wireless bluetooth receiver,five microphone interfaces and two aux RCA ports. 150/300 watts of amplifier power are available,with provided an audio output to 5 different zones within the venue,each zone has its own separate switch on/off manually operated on front panel,and each zone has its own LED indicator,shall light green for on. Built-in CHIME and SIREN circuitry with push button and volume control on front panel. Microphone input (MIC1) fitted on front panel features muting function by overriding the other inputs of MIC2,MIC3 AUX1,AUX2 with 0~30dB attenuation. Built-in Bluetooth receiver and USB player. 70/100-volt and 4/8 ohms(O) output loads. 5 Zones 100V speaker outputs with separate switch ON/OFF & LED indicator. Powerful amplifier tubes. Five 48V Phantom Power sockets support unbalanced 6.35mm jack or balanced XLR jack. Mic 1 has priority over the inputs with 0~30dB dB attenuation. High-definition display for the working status of playing programme. Built-in Chime and Siren circuitry with push-button and volume control. BASS and TREBLE tone controllers.Master volume control. Complete protection provided for output short circuit, overload, high temperature. Removable rack mounting brackets supplied. Specifications Model RH150MB RH300MB Rated Power 150W 300W Output Mode Low impedance:4/8 ohms (O), Voltage line:70V(81.7ohms),100V(166.7ohms) MIC Input Five 48V Phantom Power sockets support unbalanced 6.35mm jack or balanced XLR jack Line Input Line:10k ohms(O) 300mv,unbalanced Line Output 0.775V(0dB) FrequencyResponse 60Hz-15KHz(±3dB) THD <0.05% at 1kHz,1/3 rated power S/N Line:80dB,MIC:<75dB Tone BASS:100Hz(±10dB),TREBLE:12k Hz(±10dB) Cooling DC12V FAN Fuse AC FUSE×4A AC FUSE×6A Power Cable (3×0.75 mm )×1.5M (standard) Power Supply AC 220V ± 10% 50-60Hz (Optional) Power Consumption 190W 450W Dimension 89(H)*430(W)*340(D)mm Net Weight 9kg 11.5kg