Aura Reference MC Phono Stage

The reference Aura MC stage is the culmination of decades of electronic design development. Raga has created the ultimate, fully adjustable, three-stage, all symmetrical pre-amplifier designed purely to extract the very best performance from your moving coil cartridge and vinyl playback system.

Design Innovation
Built into a completely re-designed custom case, the Aura is dedicated to moving coil cartridges and stays clear of any compromises. Rega has avoided including any superfluous functions as they obstruct the signal path and degrade the sound quality. The Aura phono pre-amp incorporates remarkable and innovative design ideas. If you are a vinyl connoisseur, then the Aura MC is an absolute must for demonstration.

First Stage
The first stage is a symmetrical, complementary class A amplifier, using parallel connected Linear Systems ultra-low noise FET (Field Effect Transistor) transistors configured as a symmetrical compound pair input stage. The use of FET transistors ensures there is no bias current flowing in the cartridge coil so as not to upset the delicate magnetic geometry of the cartridge. The input circuit configuration also alleviates the use of any coupling components between the cartridge output and the input stage FET transistors, which would degrade the sound. The complementary ultra-low noise FET transistors are carefully graded and matched for optimum performance. This stage drives the passive high-frequency part of the RIAA equalisation stage.

Second Stage
The second stage is a symmetrical, class A, differential amplifier with a common base driver stage; this is also used as the active amplifier in the low-frequency part of the RIAA equalisation stage.

Third Stage
The third stage inverts the signal to provide the balanced output along with the output of the second stage; the third stage uses the same circuit topology as used in the second stage. The power supply is a symmetrical, discrete tracking power supply using fast diodes and a low noise voltage reference. Each stage has its own localised power supply and LED referenced current generators. To maximise headroom, the Aura has a power supply voltage, which is 60% higher than normally found in such a pre-amplifier. Very high quality, polypropylene capacitors have been used in the signal path. 1% tolerance polypropylene capacitors are used in the RIAA EQ stages and audio grade capacitors are used in the rest of the circuit. Gain, Mute and Mono switching is implemented using high-quality relays.

• Three stage, all symmetrical pre-amplifier
• Compatible with all typical low output moving coil cartridges
• Fully adjustable
• Lifetime warranty against manufacture defects

General Conditions

• Generator Source Resistance:  20 Ω (Audio Precision Z Out)
• Output Load Resistance 100 kΩ:  (Audio Precision Z In)

Input Sensitivity for 200 mV on Unbalanced Output

• 67 μV - 69.5 dB:  Gain Setting I
• 131 μV - 63.5 dB:  Gain Setting II

Gain Input to Unbalanced Output

• 63.5 dB Minimum
• 69.5 dB Maximum

Input Load

• 50, 100, 150, 300 & 400 Ω

Capacitive Load

• 1000, 2000, 3200, 4300, 5700 pF

Input Overload @ 1 kHz

• 9.6 mV - 63.5 dB:  Gain Setting I
• 4.9 mV - 69.5 dB:  Gain Setting II

Rated Output Level

• Unbalanced 200 mV
• Balanced 400 mV

Maximum Output Level

• Unbalanced 14.5 V RMS
• Balanced 29 V RMS

Balanced Output Connections

• Balanced XLR connectors pin2 positive and pin3 negative.
• The positive pin2 connection on the balanced output is the same connection as the unbalanced output.

Output Resistance

• Unbalanced 100 Ω
• Balanced 200 Ω

Absolute Minimum Output Load Resistance (for a –3 dB roll off @ 20 Hz)

• 500 Ω Unbalanced
• 1000 Ω Unbalanced

Frequency Response

• 13.5 Hz (–3 dB) to 100 kHz (–0.2 dB)
• RIAA Accuracy (Better Than)
  0.2 dB 100 Hz to 50 kHz

THD

• Typically 0.03 % @ 1 V 20 Hz 20 kHz (Bandwidth 100 Hz to 22 kHz)

Output Noise Level (Unbalanced Output, A-Weighted and 15 Ω Input Load)

• -77 dB V (69.5 dB Gain Setting I)
• -82 dB V (63.5 dB Gain Setting II)

AC Supply

• 230 V & 115 V Nominal +/- 10 %

Power Consumption

• 15.3 W

Weight

• 13Kg (28.6 lbs)

Dimensions (H x W x D)

• 435mm x 350mm x 88mm