Фонокорректоры — Rega AOS MC

The Aos MC is an MC-only phono preamplifier from the English maker Rega Research, and its circuit is based heavily on the Aura MC. It is a two-stage all-analogue amplifier free of digital control circuitry, built into a half-width aluminium enclosure of Rega's own design that also screens the circuit against stray RFI.

Key specs that matter

There is a single stereo input. Resistive loading is selectable at 70, 100, 150 or 400 ohm, and capacitive loading at 1000 or 4300 pF, and the unit leaves the factory set to 100 ohm and 1000 pF for Rega MC cartridges. Two gain settings are offered, a high one and a low one 6 dB below it, with maximum input levels of 5.1 mV and 10 mV at 1 kHz respectively. RIAA accuracy is better than plus or minus 0.2 dB from 65 Hz to 70 kHz into a 100 kohm output load. Rated output is 200 mV, maximum output 13 V RMS, and output resistance 100 ohm. Signal to noise ratio is -67 dB, and noise with a 15 ohm terminator at the low gain setting is typically -75 dBV unweighted from 85 Hz to 40 kHz. Net weight is 2.9 kg, or 3.9 kg packed. Power draw is 20 W in operation and 0.4 W in standby, from a 230, 220, 120 or 100 V supply, and the rated ambient operating range is 5 to 35 degrees C.

Engineering and use context

In the first stage, Rega uses a complementary, symmetrical class A circuit whose Linear Systems ultra-low noise FETs are graded and matched and wired as a compound pair. These FETs keep the cartridge coil free of any bias current, so its magnetic geometry is not upset, and the layout avoids coupling components between cartridge and input. It feeds the passive treble section of the RIAA equalisation. Stage two, a class A differential amplifier of symmetrical layout with a common base driver, also provides active gain for the bass portion of the RIAA network. A self-adjusting servo control keeps the input at its intended operating point as temperature changes. An automatic standby function is built in and can be adjusted through dip switches on the rear panel. A lifetime limited warranty from Rega applies to confirmed defects in manufacture.

Pairing

The Aos MC sits between a turntable carrying a moving coil cartridge and a line-level amplifier or preamp input. Rega states that it offers ample gain for low output MC cartridges. Because there are no moving magnet inputs, owners of MM cartridges need a different phono stage.

Alternatives

The Rega Aura MC is a three-stage phono stage for moving coil cartridges with five resistive loading values and a fully balanced signal path.