Интегральные усилители — Rega OSIRIS

The Osiris is an integrated amplifier from Rega Research of Southend, England, built as a dual mono design in a custom CNC machined aluminium case. Its circuit follows a minimalist approach - a passive preamplifier stage with passive volume control feeding a single high gain power amplifier stage, so there is only one stage of amplification between the input and the loudspeakers.

Key specs that matter

Rega rates the Osiris at 162 W per channel into 8 ohm and 250 W into 4 ohm, with a gain of 44 dB. Distortion plus noise is below 0.05 percent. Frequency response is 20 Hz to 26 kHz within plus 0 and minus 0.5 dB, reaching minus 1.7 dB at 10 Hz and minus 3 dB at 75 kHz. Connections comprise four line inputs on RCA sockets, a single XLR balanced input, a direct input and a record input and output, with the record output giving 215 mV into 100 kOhm. The amplifier measures 434 x 122 x 350 mm and weighs 25.6 kg. It draws 560 W in operation and 0.0 W when switched off.

Engineering and use context

There is a separate purpose-designed 400 VA toroidal transformer for each channel, wound on high-grade fully bonded core material. Reservoir capacitance amounts to 40,000 microfarads per channel using Rega K-Power capacitors, and fast recovery diodes are used for rectification throughout. The low level stages run from a regulated symmetrical tracking supply. The output stage uses eight Sanken 200 W transistors in a triple high current arrangement. Nichicon audio grade parts handle bypass and decoupling, with polyester bypass capacitors added for high frequency performance. Because the direct input skips the volume control, it lets the Osiris act as a power amplifier under an external preamplifier or processor. A CNC machined Reference remote handset comes in the box, and Rega guarantees the unit for life against defects in manufacture.

Pairing

The balanced input and four line inputs cover several sources, and since no phono section is fitted, records need an outboard phono stage feeding a line input. Rega presented the Osiris alongside its Isis CD player as a matching reference pair. Its power reserve into low impedances lets the Osiris drive demanding floorstanding loudspeakers.

Alternatives

The Rega Aethos is the dual mono integrated amplifier one step below, rated at 125 W per channel into 8 ohm, with four 160 W Sanken output transistors per channel, a 433 x 95 x 360 mm case and a weight of 17.5 kg.