Фонокорректоры — Auris Audio Auris Phonio

The Auris Phonio is a phono preamplifier from Auris Audio that contains two entirely separate phono stages, dedicated respectively to MM and MC pickups. According to the maker, the adjustable gain lets it accept cartridges with very low as well as very high output levels. Each stage has its own input sockets and its own input preamplifier circuit, so the two cartridge types never share a gain path. The unit comes with a dedicated low-noise linear power supply, and Auris lists it at EUR 959 including tax.

Key specs that matter

Gain on the MM input is fixed at 43.2 dB, while the MC input offers 60 dB, 66 dB or 69 dB. Maximum input level at 1 kHz is 60 mV for MM and 4 mV for MC at low gain, and both stages reach a maximum output of 5 V. Unweighted SNR exceeds 88 dB for MM and 68 dB for MC. THD+N is 0.005% at 1 V for MM and 0.025% at 1 V for MC, the latter measured over a 100 Hz to 22 kHz bandwidth at low gain. Frequency response from 20 Hz to 80 kHz holds within 0.3 dB on MM and 0.2 dB on MC, and RIAA accuracy follows the same tolerances.

Engineering and use context

Auris describes the circuit as an ultra low noise, low distortion design. Low-noise MELF resistors and WIMA capacitors were chosen to hit the target RIAA curve, and Sound Plus operational amplifiers are connected in what the company calls an advanced topology for accurate equalisation with suppressed noise. Audio grade electrolytic capacitors are used as well. The aluminium enclosure shields the internal circuit from RFI and keeps the electromagnetic field of the power transformer away from the phono stage. The power supply combines ultra low noise LDO regulators with more than 5,000 uF of filter capacitance, and inside the Phonio further LDO regulators work together with a low-noise BJT supply topology. The external linear supply was built only for this device and is protected against current overload, short circuit and thermal overload.

Pairing

The MM input is loaded at 47 kohm in parallel with 150 pF. For moving coil cartridges, DIP switches set resistance at 400, 150, 100 or 70 ohm for each channel, and capacitance at 1,000, 2,000, 3,200 or 4,200 pF. MC gain is chosen with the same kind of switches, one position for each of the three levels. Switching between the MM and MC stages is done with a selector, and Auris states that the loading options are there to match the stage to a given moving coil cartridge.

Alternatives

Auris Audio also lists the aRIAA as a separate phono stage in its current range.