Усилители мощности стерео — Rotel RMB-1504

The Rotel RMB-1504 is a four-channel Class AB amplifier delivering 70 W per channel into 8 ohm and 115 W into 4 ohm loads. Rotel positions it for object based overhead speakers in home theatre systems and for custom installation multi-room audio, and it draws on more than 60 years of amplifier design at the company.

Key specs that matter

Rotel gives THD as under 0.03% over 20 Hz to 20 kHz into 8 ohm, and intermodulation distortion is below 0.03% as well. The frequency response stretches from 10 Hz to 100 kHz within 1 dB. The damping factor is greater than 200, while noise is 115 dB down, IHF A weighted. Gain is 26 dB. The inputs need 1 V for full output and present an impedance of 20 kOhm. The chassis measures 431 x 144 x 443 mm with a 3U front panel of 132.6 mm, and the net weight is 14.9 kg. It comes in black.

Engineering and use context

A factory built toroidal transformer, described by Rotel as oversized, works with high efficiency capacitors to feed high current output transistors. Speakers connect through 5-way binding posts. For installation work the amplifier provides a 12 volt trigger input and output, so it can be switched on together with other equipment and pass the command on, and a three-position slide switch at the back chooses between manual power, automatic signal sensing that wakes the amplifier when a signal reaches the inputs and returns it to standby several minutes after the signal stops, and remote 12 volt trigger control. Front panel input level controls set the level of each channel on the amplifier itself. The RCA inputs can be linked, a mono switch is fitted, and signal output link connectors pass the input on to further amplifiers. A circuit breaker and protection circuitry against fault conditions are fitted, with indicators on the front panel. The output devices are discrete. Rack ears are included. Power consumption is 450 W, standby consumption is under 0.5 W, and heat output is listed at 810 BTU per hour. The North American version runs on 120 V at 60 Hz.

Pairing

In a home theatre, the four channels can drive height speakers alongside a surround receiver or processor whose own amplification covers the main channels, with the trigger link turning the RMB-1504 on together with it. In a multi-room system the same four channels can supply two stereo zones, and signal sensing removes the need for a trigger cable where the source cannot provide one.

Alternatives

The Rotel RMB-1506 is the six-channel multi-zone amplifier of the brand, rated at 50 W per channel into 8 ohm and 80 W into 4 ohm with all channels driven.