Introducing the Rega Aethos

Posted by The Sound Organisation on Nov 6th 2019

Rega Research has officially announced their newest integrated amplifier, the Rega Aethos. This long awaited amplifier joins the Osiris Amplifier in Rega's Reference line of equipment. The Aethos improves upon the award-winning Elex-R and Elicit-R amplifiers and comes in an all-new, custom designed case.

From Rega:

We are extremely pleased to announce the official launch of the AETHOS stereo integrated amplifier.The Aethos stereo integrated amplifier is housed in a brand new custom designed case. Employing four 160W 16 Amp output transistors per channel, this delivers 156 W per channel into 6 Ω. Dual mono design using a custom wound toroidal transformer and regulated supplies for the sensitive amplification and driver stages. The pre-amplifier stage uses class-A discrete circuitry throughout. The Aethos is a no compromise product with one goal, to deliver your music as faithfully as possible.

Built to Rega's high standards of reliability and quality to ensure many years of musical enjoyment.Our time, effort & money has been spent on developing the circuit and construction utilizing the highest specification of components throughout. As part of the design we have included useful features such as the switchable direct input and pre-amplifier output, to enable the new Aethos amplifier to be used in a wide combination of systems. The headphone socket has been integrated such that the speaker switching is performed by the output mute relay so as not to obstruct the signal path and degrade the sound quality. We have chosen not to include a phono stage to keep this product true to its no compromise goals. Rega has taken the design concepts underpinning the multi award winning and hugely successful Elex-R and Elicit-R and propelled the performance to the next level with features such as fully discrete FET based line amplifier, polypropylene capacitors throughout the signal path, K-Power reservoir capacitors, power amplifier regulated supply and a high current output stage comprising of four 160w Sanken output transistors per channel.This product has been designed to accompany the Aura MC stage and Planar 10 turntable (with Apheta 3 MC) to create a system delivering performance well beyond anything else at this price point.

Additional Features of the Rega Aethos:

Volume Control and Line Amplifier Technology

The Aethos uses a high performance combined feedback and passive volume control plus line amplifier, which was originally developed for the Elex-R. Improvements have been made to the volume control and line amplifier stages in the Aethos with the use of discrete FET input operational amplifiers using the Linear Systems LSK389 FET and the well-respected RK27 ‘Blue Velvet’ potentiometer. The feedback and input levels are varied to set the required volume level. The level and tracking between the two channels is set by the close tolerance parts in the pre-amplifier circuit and less by the actual potentiometer itself, thus keeping the mismatch of channels due to volume control tracking irregularities to a minimum, further improving on the performance of the RK27 potentiometer. As well as keeping tracking irregularities to a minimum, this method also reduces noise and input overload as the control will only ‘use’ the required gain to amplify the signal. This form of volume control is normally only found in professional broadcast environments where accurate low noise control of levels is required.

Power Amplifier Technology

The power amplifier used in the Aethos is an improved higher power version of the power amplifier used in the Elicit-R and Elex-R. The output amplifier used in the Aethos, was born after extensive research by Rega engineers to develop a low source impedance emitter follower Class-A driver stage. This is based around two complementary pairs of 160w Sanken Darlington output transistors. The technical and sonic improvement gained by the use of low impedance drivers is well known, however, it can feature high standing currents in the driver stage when using standard transistor configurations. By combining the low impedance driver with the Sanken Darlington transistors (with their imbedded thermal bias network running at a lower standing current), this combination forms a complementary emitter follower emulating Class-A conditions with good thermal stability and lower standing currents in the driver stage. Due to the nature of the Rega power amplifier circuit we are able to run two complete output stages in parallel, this includes the output transistors, bias network and pre diver transistor this is instead of paralleling just the output transistors as normally found. This ensures the 125 watt output is achieved with complete ease.

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Technical Specifications:

Power outputs at rated 230/115 V supply voltage:
125 W RMS both channels driven into the rated load of 8 Ω
156 W RMS both channels driven into 6 Ω
Note: Continued high level use into 6 Ω may cause the case to exceed 40 °C above the ambient temperature and activate the thermal shutdown.

Headphone output:
No load
12.5 V
32 Ω 2.7 V
54 Ω 4 V
300 Ω 9 V
Source impedance 109 Ω

Record output:
Record output level (with rated input levels) 219 mV
Record output impedance 560 Ω

Pre-amp output:
Pre-amp output level (with rated input levels) 840 mV
Pre-amp output impedance 100 Ω

Input sensitivities for rated output level:
Input 1-5 and record input sensitivity 224 mV @ 17 kΩ
Maximum input level 11.5 V (record output amplifier overload point)
Direct input sensitivity 840 mV @ 50 kΩ
Power amplifier gain 31.6 dB

Frequency response @ 100 W into 8 Ω:
Line input 1-5 and record 10 Hz (-0.8 dB point) to 30 kHz (-0.5 dB point)
Direct input 10 Hz (-0.8 dB point) to 50 kHz (-0.5 dB point)

THD+Noise @ 100 W into 8 Ω:
Direct input (Power amplifier only)Typically 0.007% @ 1kHz (measurement bandwidth 22 Hz to 30 kHz)

Line input Typically 0.007% @ 1kHz (measurement bandwidth 22Hz to 30KHz)
Power consumption Maximum output: 415 W @ 230 V / 220 V / 115 V / 100 V into the rated load of 124 W RMS into 8 Ω

Fuse ratings T3.15 AL 250 V - 230 V/ 50 Hz and 220 V / 60 Hz
T6.3 AL 250 V - 115 V / 60 Hz and 100 V 50/60 Hz

Dimensions W 17" x H 3.75" x D 14.17" (including speaker terminals)

Weight 38.6 lbs

The  Rega Aethos will arrive in the U.S. stores in early 2020. If you're interested in purchasing one or scheduling a time to listen to an Aethos, click here to find your nearest Rega retailer.