Rega AURA Manual De Instrucciones página 5

05
Introduction and design innovation
The function of a phono pre-amplifier is to match the output from a pickup cartridge to the input of a line level amplifier. It is required to
amplify the very low signals produced by the cartridge and 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 13kg, 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.