Rotel RMB-1504

Four Class AB channels for home cinema and multi-zone installations Rotel RMB-1504 is a Class AB multichannel power amplifier rated at 70 W per channel into 8 ohms and 115 W per channel into 4 ohms with all channels driven, designed for home cinema systems and distributed audio. The power supply is sized to support several loudspeakers at the same time, a more demanding condition than testing one channel alone. A large in-house toroidal transformer, high-efficiency capacitors and high-current output transistors provide the required reserve, while discrete circuits and trigger functions simplify installation in racks and dedicated cinema rooms. Key features Four channels of Class AB amplification. 70 W per channel into 8 ohms with all channels driven. 115 W per channel into 4 ohms with all channels driven. THD below 0.03%. Large in-house toroidal transformer. High-efficiency capacitors and high-current output transistors. RCA inputs with link outputs. Damping factor above 200. Power with all channels driven RMB-1504 delivers 70 W per channel into 8 ohms and 115 W per channel into 4 ohms with all four channels active. The all-channels-driven figure is important in a multichannel system because it describes supply capability when several loudspeakers demand current simultaneously during a dynamic soundtrack. High-current power supply A large in-house toroidal transformer supports the power section. Its reserve is sized for simultaneous channel use and reduces the risk that peaks on one loudspeaker take energy from the others, maintaining more stable behaviour across the system. Capacitors and transients High-efficiency capacitors and high-current output transistors support transients and bass when effects involve several channels. Low internal resistance helps transfer energy rapidly to the output stages without introducing a slow response under load. Class AB and response Declared THD is below 0.03% and frequency response runs from 10 Hz to 100 kHz within ±1 dB. A damping factor above 200 contributes to woofer control, particularly useful when several large loudspeakers are driven in the same room. Inputs and AV processor RCA inputs with link outputs connect surround processors and preamplifiers with different outputs. Front attenuation controls, automatic signal sensing and 12 V triggers are designed for distributed installations; the model is offered in a single finish. The power amplifier remains independent of decoding and can be retained when the upstream processor changes. Trigger and installation The 12 V trigger allows the power amplifier to switch on with the processor or a control system. Installation functions reduce the need for manual intervention when the unit is placed in a technical rack or dedicated cinema room. Chassis and thermal management The chassis measures 431 x 144 x 443 mm and weighs 14.9 kg. Heatsinks, power supply and amplification modules occupy most of the structure and are distributed to encourage cooling while keeping input sections away from the main sources of heat and magnetic field.