Rega Aos MC MK4 Phono Stage Pre-Amplifier

• Pure Analogue
• The AOS is a two stage “all analogue amplifier” with no digital control circuitry. The fully aluminium case screens the internal circuit from any stray RFI signals. Our designers have avoided including any unnecessary components or circuits that may degrade the signal path. The AOS incorporates many innovative design ideas including a self-adjusting servo control which compensates for any variations in ambient or operating temperature.
• The AOS utilises parallel connected, low noise FETs (Field Effect Transistors) configured as a compound pair. 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 MC input has the provision for selecting resistive input loading of 70 Ω to 400 Ω and capacitive loading of 1000 pF to 4300 pF. The input sensitivity can be changed by 6 dB via the back panel. An automatic standby feature has also been added which puts the unit to sleep after a period of no signal. This can be deactivated via dip switches located on the rear panel.
• Key Features
• Dedicated moving coil phono stage
• Fully adjustable for loading
• Factory pre-set for use with all Rega MC cartridges
• Circuit design based on the Reference Aura MC
• Custom aluminium design half width case
• Automatic standby function
• Lifetime warranty against manufacture defects
• First Stage: The first stage is a symmetrical, complementary class A amplifier, using Linear Systems ultra-low noise FET (Field Effect Transistor) transistors. 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 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.

• Technical Specifications
• Input Load
  70, 100, 150, & 400Ω
• Capacitive Load
  1000, 4300pF
• RIAA Accuracy (100kΩ output load)
  Better than ±0.2dB 65Hz to 70kHz
• Frequency Response
  17.5 Hz (-3 dB) to 100 kHz (-0.2 dB)
• THD
  0.03%
• Input Sensitivity
  69.3 dB (Gain Setting I), 63.5 dB (Gain Setting II)
• Power consumption in Standby
  0.4W
• Power Consumption
  20W
• Dimensions (WxHxD)
  220 x 80 x 330 mm
• Weight
  2.9Kg
• Load settings for adjustable MC stages
  Gain (0dB high gain setting)69.3dB at 1kHzGain (-6dB low gain setting)63.5dB at 1kHz
  
  

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