Préampli phono MC Rega AOS MC

A new phono preamplifier from Rega is always an event. The manufacturer’s catalog lacked a more ambitious product than the Aria, and for this purpose Rega designed the AOS, which is dedicated exclusively to low-output MC cartridges.

Rega AOS: Settings

This RIAA preamplifier has the particularity of being compatible only with low-output MC cartridges.

Designed to adapt to a wide range of MC cartridges, the AOS offers several resistive loading options (70, 100, 150 and 400 ohms) and capacitive options (1000, 4300 pF), as well as gain adjustment of 63.5 or 69.3 dB. This flexibility makes it possible to optimize the cartridge/system matching and ensure coherent, balanced and dynamic reproduction depending on the installed configuration.
The internal layout and short signal path guarantee stable transmission while limiting losses and disturbances.

Rega AOS: Chassis

The Rega AOS comes in a “shoebox-style” enclosure typical of Rega, also found on the Brio and Aria. This aluminum chassis helps reduce electromagnetic interference and preserve signal integrity.
On the front panel, the power button is located on the right and the REGA logo is backlit in red at the center.

On the rear panel, there is an RCA input dedicated to MC cartridges and a stereo RCA line output for easy integration with any amplifier or preamplifier. The different adjustments are accessible via 2 x 4 switches. There is also a ground connection and a switch that allows the device to be set to “auto-standby” or not. This function activates after approximately 1 hour without signal present at the input.

Rega AOS: Electronics

The AOS MC is based on a two-stage analog design using very low-noise FET transistors. Its symmetrical circuit and architecture use only top-quality components. The MC input uses FETs (field-effect transistors) connected in parallel and configured in pairs.

FET transistors prevent current from flowing into the cartridge coil, thus preserving its delicate magnetic balance. Each channel is powered individually and separately by two power supplies. Nichicon FC electrolytic capacitors are used at strategic positions in the power supplies.

In the signal path and RIAA correction, only ICEL and WIMA polypropylene capacitors and discrete components are used. Each technical choice aims to extract with precision the micro-information contained in the groove.

Rega AOS: Test and Listening

Listening with an MC cartridge is unsurprising. All the qualities of tone, dynamics and articulation typical of REGA preamplifiers are present. The remarkable dynamics deliver an engaging and communicative rhythm. The bass is deep and highly articulated, offering strong presence and excellent speaker control.

It is also noticeable that the AOS offers a very low noise level, allowing a wide dynamic range and surprising transparency, making it possible to hear reverberations on voices and the harmonics of each instrument. The AOS MC also excels in the separation of different sections and registers.

The Rega AOS is an extremely balanced phono preamplifier that reveals the quality of the cartridge and, of course, the recordings. It highlights the timbre of an instrument and its harmonic richness.

This natural, neutral reproduction, without any aggressiveness while remaining dynamic and lively, gives the music remarkable swing, fluidity and realism.

Highly recommended +++.