Rega AOS Moving Coil Phono Stage – Premium Adjustable MC Pre-Amplifier Exceptional Moving Coil Phono Amplification for Audiophiles The Rega AOS is a dedicated, no-compromise moving coil (MC) phono stage engineered to deliver outstanding vinyl playback performance. Drawing heavily from the acclaimed circuit design of Rega's award-winning Aura reference MC phono stage, the AOS offers remarkable clarity, exceptional detail retrieval, and a highly realistic listening experience that brings every record collection to life. Housed in a bespoke half-width aluminium chassis, the AOS is designed for discerning vinyl enthusiasts seeking the ultimate performance from their moving coil cartridges. Designed for Maximum Cartridge Compatibility The AOS has been developed to work seamlessly with a wide range of moving coil cartridges. With ample gain for low-output MC cartridges and extensive loading adjustment options, it provides precise cartridge matching and optimal sonic performance regardless of the cartridge selected. Factory pre-configured for all Rega moving coil cartridges, the AOS also offers comprehensive user-adjustable settings for audiophiles who wish to fine-tune their system. Pure Analogue Signal Path Built as a true two-stage analogue amplifier, the AOS contains no digital control circuitry. Every aspect of the design focuses on preserving signal integrity and minimising unwanted interference. The custom-machined aluminium enclosure provides effective shielding against radio frequency interference (RFI), while the carefully optimised signal path eliminates unnecessary components that could compromise audio quality. An innovative self-adjusting servo control system automatically compensates for temperature variations, ensuring consistent performance in all operating conditions. Advanced Low-Noise FET Technology At the heart of the AOS are parallel-connected ultra-low-noise Field Effect Transistors (FETs) arranged in a sophisticated compound-pair configuration. Unlike conventional transistor designs, the FET architecture ensures that no bias current flows through the cartridge coils, preserving the delicate magnetic structure of the cartridge and maintaining exceptional signal purity. The MC input stage provides adjustable resistive loading from 70Ω to 400Ω and capacitive loading from 1000pF to 4300pF, allowing precise optimisation for a broad range of moving coil cartridges. Input sensitivity can also be increased by 6dB via the rear panel for ultra-low-output cartridges. For energy efficiency, an automatic standby function places the unit into sleep mode after periods of inactivity, with the option to disable this feature through rear-panel DIP switches. Key Features Dedicated moving coil (MC) phono stage Fully adjustable cartridge loading settings Factory preset for all Rega MC cartridges Circuit topology derived from the Rega Aura reference phono stage Ultra-low-noise Class A analogue design Custom half-width aluminium chassis Adjustable gain for low-output MC cartridges Automatic standby mode with user override Precision-matched FET input stage Lifetime warranty against manufacturing defects First Stage: Ultra-Low Noise Class A Input Amplifier The first amplification stage employs a symmetrical complementary Class A circuit using carefully selected and matched Linear Systems ultra-low-noise FET transistors. This advanced topology ensures there is no bias current flowing through the cartridge coils, preventing any disruption to the cartridge's magnetic geometry. The direct-coupled input design also eliminates the need for signal-degrading coupling components between the cartridge and amplifier stage. The precisely matched FET devices provide exceptional noise performance and drive the passive high-frequency section of the RIAA equalisation network with remarkable accuracy and transparency. Second Stage: Precision Differential Class A Amplification The second stage utilises a symmetrical Class A differential amplifier with a common-base driver configuration. This stage performs dual functions: providing high-gain signal amplification while simultaneously serving as the active amplification section for the low-frequency portion of the RIAA equalisation circuit. The result is exceptional tonal accuracy, precise bass reproduction, and a natural, engaging musical presentation that faithfully reproduces the original recording. Specification Value Input Load 70, 100, 150, & 400 Ω Capacitive Load 1000, 4300 pF RIAA Accuracy (100 kΩ output load) Better than ±0.2 dB (65 Hz – 70 kHz) 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 (Standby) 0.4 W Power Consumption 20 W Dimensions (W × H × D) 220 × 80 × 330 mm Weight 2.9 kg
