Design innovation
Rega Aura is the fully adjustable Reference MC phono stage, with a symmetrical three-stage Class A architecture and RCA and XLR analogue outputs.
Aura is Rega's Reference MC phono stage and is dedicated to low-output moving-coil cartridges. The circuit is entirely symmetrical and arranged in three stages, with adjustments designed to match loading and gain to the cartridge in use. The design avoids unnecessary functions in the signal path and uses a custom chassis developed specifically for this electronics platform.
Key features
- Symmetrical three-stage MC preamplifier
- Compatible with typical low-output MC cartridges
- Fully adjustable
First Class A stage
The first stage uses ultra-low-noise Linear Systems FET transistors connected in parallel and arranged as a compound pair of symmetrical type. The complementary Class A topology avoids bias current in the cartridge coil and reduces the need for coupling components between cartridge output and phono-stage input. The FETs are selected and matched, and drive the passive high-frequency portion of the RIAA equalisation, keeping the first section of the signal path as clean as possible.
Second and third stages
A symmetrical differential Class A amplifier with common-base driver forms the second stage, which also provides active amplification for the low-frequency portion of the RIAA network. The same topology is used by the third stage, which inverts the signal and, combined with what the second stage delivers, creates the balanced output. This architecture therefore provides both RCA outputs and balanced XLR connections while keeping the path consistent with the symmetrical design.
Power supply and adjustment
The power supply is symmetrical, discrete and regulated, with fast diodes and a voltage reference of low-noise type; every stage also has a local supply of its own, with current generators referenced to LEDs. Supply voltage is higher than normally used in a phono stage to increase headroom. Resistive and capacitive loading are adjustable together with gain, while Gain, Mute and Mono functions are switched through high-quality relays.
Components and signal path
Rega uses high-quality polypropylene capacitors throughout the signal path and tightly toleranced components in the RIAA equalisation networks. Keeping the three stages separate and assigning dedicated local supplies reduces interaction between sections. Aura is therefore conceived as a specialised phono stage without functions unrelated to MC playback, while providing enough adjustment to suit numerous low-output cartridges.
