Earth Grounding; Installation - Rega Aura Manual

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Introduction and Design Innovation
1 Earth Grounding and Installation
2 Connections and Supplied Cables
2 Cartridge Selection and Powering Up
2 Gain and Capacitance
3 Load Settings, Mute and Mono
4 Specifications
9 Warranty and Warnings
Introduction and Design Innovation
The function of a phono pre-amplifier is to match the output from a pick up cartridge to the input of a line level amplifier. It is
required to amplify the very low signals produced by the cartridge and also to equalise the sound in accordance with the RIAA
record cutting standard. Rega believes that moving coil and moving magnet cartridges require different types of phono pre-
amplifiers to achieve optimum performance. The Aura is therefore dedicated to moving coil cartridges and stays clear of any
compromises. We have 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. For those interested in the technical details, these
innovations are described more fully in the next section of this manual. Alternatively, you can simply switch on, sit back and let the
Aura speak for itself.
The Rega Aura is a three stage, all symmetrical pre-amplifier. 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.
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. 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.

Earth Grounding

The Aura uses a Class I earth system, where the case metalwork is connected to the line safety earth, by means of the mains lead.
The internal signal earth is linked to this earth by the use of a network to eliminate the risk of earth/ground loops. This earth method
provides a safe and efficient discharge path for any static charge generated by the cartridge.

Installation

The Aura will work well on most surfaces, such as a shelf or a table, provided there is sufficient air around it to prevent overheating.
To avoid any possible magnetic interference and increased hum levels, position the Aura as far away from the turntable as the
tonearm lead will allow. If possible, try to place the Aura to the left of the turntable. Ideally equipment should be placed next to one
another in a line. This keeps the most delicate electronics away from other transformers. Try not to stack other hi-fi components,
on top of, or directly beneath the Aura. If this is unavoidable, use an equipment stand. The heat produced by the amplifier, although
minimal, is dispersed to the air by the case, particularly the underside. Ensure that the case has an uninterrupted air passage
around it.
The Aura weighs 13 kg, so take great care when lifting and please ensure the shelf or stand you are using can safely support this
weight. Please refer to your stand manufacturer's manual for maximum load capacity.
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