Усилители мощности стерео — Rotel RB-1590

The Rotel RB-1590 is a Class AB two-channel amplifier from the main Rotel range that delivers 350 W per channel into 8 ohm with both channels driven and 648 W per channel into 4 ohm. Rotel lays out the circuit as a true monoblock design for each channel, aiming at maximum signal separation, and houses it in a 5U chassis with rack ears included.

Key specs that matter

Harmonic distortion measures below 0.03% across 20 Hz to 20 kHz, and intermodulation distortion, measured at 60 Hz and 7 kHz in a 4 to 1 ratio, is also below 0.03%. The frequency response covers 10 Hz to 100 kHz within 0.5 dB. Signal to noise ratio reaches 120 dB, IHF A weighted, the damping factor is 300 and channel separation exceeds 50 dB. Gain is 27.5 dB through RCA and 23.5 dB through XLR. Input sensitivity is 2.2 V for the RCA sockets and 3.5 V for the XLR sockets, which load the source with 12 kOhm and 100 kOhm. The amplifier measures 431 x 237 x 456 mm and weighs 38.1 kg.

Engineering and use context

Its supply uses twin toroidal transformers that Rotel makes itself, one feeding each channel, and eight BHC capacitors made in Britain and chosen for low loss. This dual supply structure is what allows the monoblock layout inside a single case. In operation the RB-1590 draws 800 W from the mains and 0.5 W in standby, and the rated heat load is 2,100 BTU/h at 1/8 power. The North American model is specified for 120 V at 60 Hz. A rear panel toggle chooses between the RCA and XLR inputs, and a 12 volt trigger input with a matching output lets the amplifier be switched on remotely and pass the signal along. Thermal and over-current protection watches the temperature of the output devices and the current through them, shuts the amplifier down if safe limits are exceeded and signals this by a blinking power indicator. Speakers connect to four pairs of colour coded binding posts, two per channel, which accept bare wire, lugs or dual banana plugs. The 5U height and supplied ears allow it to be mounted in a standard equipment rack instead of on a shelf.

Pairing

Having both XLR and RCA sockets lets the RB-1590 follow either type of preamplifier, and the published sensitivity figures show the drive each input needs for full output. Its high output into low loads is aimed at low impedance loudspeakers that need a large current reserve, and its considerable weight calls for a solid rack or shelf.

Alternatives

The Rotel RB-1582 MkII is the smaller stereo power amplifier of the range, rated at 200 W per channel into 8 ohm and 323 W into 4 ohm in a 3U case.