Audio T Verdict
The Rega Mercury is a reference pre-amplifier for customers building a high-performance separates system around a dedicated power amplifier, carefully selected analogue sources and modern digital playback.
Its fully discrete symmetrical circuitry, substantial linear power supply and exceptionally low noise floor are complemented by a high-performance DAC, powerful discrete headphone amplifier, balanced and unbalanced outputs, record loop, AV bypass and comprehensive system control.
The Mercury is the natural partner for the Rega Solis Reference Stereo Power Amplifier, but it can also be used with other compatible power amplifiers or active loudspeakers. At this level, we strongly recommend an in-store or home demonstration using source components and speakers similar to your own.
Rega Mercury Reference Pre-Amplifier
The Rega Mercury represents the culmination of almost four decades of Rega solid-state amplifier development.
Its primary design objective is to preserve the smallest musical details by maintaining an exceptionally low noise floor and minimising distortion throughout the signal path.
The Mercury combines a fully discrete analogue pre-amplifier with a high-performance digital-to-analogue converter, discrete headphone amplifier, record loop, AV bypass, balanced and unbalanced connections, full-colour display and extensive system control.
It is housed within a custom-designed CNC-machined aluminium enclosure and is Rega's most complex electronic product by component count.
What Does a Pre-Amplifier Do?
A pre-amplifier selects the source, controls listening volume and provides the correctly regulated signal required by a separate power amplifier.
Keeping the pre-amplifier and power amplifier in separate enclosures allows sensitive low-level circuitry to be positioned away from the transformers, output devices and high-current power supply of the power amplifier.
This separation can reduce electrical and magnetic interference while providing greater flexibility when selecting and upgrading individual system components.
The Mercury does not drive passive loudspeakers directly. It must be connected to a compatible power amplifier, such as the Rega Solis, or to suitable active loudspeakers with their own internal amplification.
Fully Discrete Symmetrical Circuitry
The Mercury uses discrete, differentially driven and fully symmetrical circuitry throughout the core signal path.
Its common-base voltage amplifier stages are designed to provide high linearity, wide bandwidth and strong voltage and current drive while keeping distortion to a minimum.
Complementary Class A output stages are used within the pre-amplifier circuitry, while critical amplification sections employ Linear Systems ultra-low-noise FET transistors arranged as differential quad pairs.
This circuit topology is related to technology used within the second stage of Rega's Aura Reference moving coil phono stage.
- Fully discrete core signal path
- Differentially driven symmetrical amplifier circuitry
- Common-base voltage amplifier stages
- Complementary Class A output stages
- Linear Systems ultra-low-noise FET transistors
- DC-coupled main unbalanced output
- DC protection for the main and headphone outputs
Alps Blue Velvet Volume Control
The Mercury uses an Alps Blue Velvet RK27 motorised volume control based on the topology developed for Rega's Osiris reference integrated amplifier.
The potentiometer is partnered with symmetrical common-base driver stages rather than being used as a simple passive level control.
Volume can be adjusted from the front panel or with the supplied Orbit remote control. The physical control rotates automatically when volume is changed remotely.
The balanced and unbalanced preamplifier outputs and the headphone output follow the Mercury volume control. The fixed-level record output does not.
Substantial Linear Power Supply
A generously rated toroidal transformer feeds a discrete symmetrical tracking power supply.
Fast rectifier diodes, low-noise voltage references, localised capacitance and multiplier power supplies are used throughout the design.
Individual stages have their own local regulation and LED-referenced current generators, helping isolate sensitive circuits from one another.
The Mercury operates with a power supply voltage around 60 per cent higher than would normally be found in a conventional pre-amplifier. This provides additional headroom for demanding signal peaks.
Analogue Input Connectivity
The Mercury provides five main analogue inputs, comprising one balanced XLR input and four unbalanced RCA inputs.
Balanced Input 1
Input 1 uses balanced XLR connections for compatible phono stages, CD players, DACs and streamers.
It operates at standard consumer line level and is useful where balanced equipment or longer cable runs are required.
Unbalanced Inputs 2 to 5
Inputs 2 to 5 use conventional stereo RCA connections.
They can accommodate phono stages, CD players, streamers, external DACs, tuners and other line-level analogue sources.
Record Input
A separate unbalanced Record input is provided for the monitor output of a cassette deck, recorder, sound card or other compatible recording device.
The supplied remote control allows the Record function to be selected independently.
Balanced or Unbalanced Connections?
The Mercury provides both balanced XLR and unbalanced RCA connections, but Rega recommends using unbalanced connections between the Mercury and Solis for optimum sound quality in most domestic systems.
The core circuits of both products are unbalanced. Additional circuitry is therefore required to create their balanced inputs and outputs.
Balanced connections are particularly useful for professional installations and systems using long cable runs, where their ability to reject externally induced noise can provide a practical advantage.
In a normal domestic system with short interconnects, balanced operation does not automatically provide better sound. Your Audio T store can advise which connection is most appropriate for your equipment and installation.
Balanced and Unbalanced Preamplifier Outputs
The Mercury includes both balanced XLR and unbalanced RCA preamplifier outputs.
Both outputs follow the Mercury volume control and can be used with compatible power amplifiers or active loudspeakers.
The balanced and unbalanced outputs can also provide flexibility where more than one compatible power amplifier or system zone needs to be connected.
Designed for the Rega Solis
The
Rega Solis Reference Stereo Power Amplifier
was developed as the Mercury's ideal partner.
The Solis delivers 168W per channel into 8 ohms and 305W per channel into 4 ohms, giving the combination the power and current delivery required for a wide range of high-performance loudspeakers.
Separating the sensitive Mercury circuitry from the transformers and high-current output stages inside the Solis also allows each product to concentrate on its own role within the system.
A Rega Couple 3 interconnect and two trigger cables are supplied with the Mercury to assist with system installation.
High-Performance Digital-to-Analogue Converter
The Mercury contains a high-performance Rega digital-to-analogue converter using two parallel-connected Wolfson DACs.
The recovered digital data feeds the DACs before passing through a fully symmetrical post-conversion analogue filter and amplifier stage.
Linear Systems ultra-low-noise FET devices are used within the analogue filter input stage, while the circuit topology draws on Rega's experience with its reference products and Saturn CD player.
Five selectable digital filters allow the conversion response to be adjusted according to the incoming PCM sample rate and personal preference.
Two Coaxial Digital Inputs
Two galvanically isolated coaxial S/PDIF inputs are provided for compatible digital sources.
These inputs support two-channel PCM audio from 16 to 24 bit at sampling rates from 32kHz to 192kHz.
Suitable sources may include network streamers, CD transports, televisions, media players and other equipment with an RCA coaxial digital output.
Two Optical Digital Inputs
Two Toslink optical inputs provide additional connectivity for televisions, streamers, games consoles and other compatible digital sources.
Optical connections support two-channel PCM from 16 to 24 bit at sampling rates from 32kHz to 192kHz.
Dolby Digital, DTS and other compressed surround formats are not supported. A connected television or AV product should be configured to output two-channel PCM or LPCM.
Galvanically Isolated Asynchronous USB
The USB 2.0 Type-B input can connect to a compatible computer, mobile device or digital source.
It is galvanically isolated from the rest of the Mercury and uses its own dedicated power supply.
Re-clocking is applied to the recovered PCM and DSD data, with two high-stability oscillator modules providing low-jitter clocks for domestic and professional sample-rate families.
- Asynchronous USB operation
- USB 2.0 Type-B connection
- PCM from 16 to 32 bit
- PCM sampling rates from 44.1kHz to 192kHz
- DSD64 supported through DoP
- Dedicated isolated USB power supply
- No power drawn from the connected USB host
PCM and DSD Playback
The coaxial and optical inputs support two-channel PCM audio only.
The USB input supports PCM up to 32-bit/192kHz and DSD64 through DoP, or DSD over PCM.
The connected computer or source must support DoP output for DSD playback.
Two DSD operating modes are available. DSD Direct minimises processing, while DSD Plus applies additional filtering to reduce ultrasonic noise created during DSD encoding.
Connecting a Music Streamer
The Mercury does not include network streaming, but it can be connected to a wide range of dedicated music streamers.
A streamer can connect digitally so that the Mercury performs the digital-to-analogue conversion, or by analogue output if you prefer to use the DAC inside the streamer.
Bluesound Node Icon
The
Bluesound Node Icon
can connect through a coaxial, optical, balanced or unbalanced connection.
Using a digital output allows the Mercury DAC to perform conversion, while an analogue connection uses the Node Icon's internal DAC.
Set the streamer to fixed output when using the Mercury as the system volume control.
WiiM Ultra
The
WiiM Ultra
provides an accessible way to add app-controlled streaming, multiroom playback and music services.
It can connect digitally through its coaxial or optical output, allowing the Mercury's dual-Wolfson DAC arrangement to handle conversion.
Its output should be fixed when the Mercury is controlling volume.
Other Digital Sources
Other streamers and digital transports can be used provided they offer a compatible coaxial, optical or USB output.
Audio T can arrange comparative demonstrations between digital and analogue connection methods.
Reference Vinyl Playback
The Mercury does not contain an internal phono stage. A turntable must be connected through a suitable external moving magnet or moving coil phono stage.
Rega Aura Reference MC
The
Rega Aura Reference MC
is the natural choice for a reference Rega moving coil vinyl system.
It can connect to the Mercury using balanced XLR or unbalanced RCA connections.
Rega Aos MC
The
Rega Aos MC
offers adjustable gain and loading for a wide range of moving coil cartridges.
It connects through one of the Mercury's unbalanced RCA line inputs.
Rega Naia
The
Rega Naia
with Aphelion 2 cartridge and Aura phono stage forms Rega's reference vinyl source system.
Audio T can demonstrate the complete combination with the Mercury and Solis.
Rega Isis CD Player
The
Rega Isis CD player
is a natural digital source for a complete Rega reference system.
It can connect through its analogue output, allowing the Isis to perform conversion, or by digital connection where appropriate.
Comparing connection methods during a demonstration can help establish which DAC and analogue output stage best suits the wider system.
Discrete Headphone Amplifier
The Mercury includes a dedicated discrete headphone amplifier based on the same symmetrical common-base driver-stage principles used within the Solis power amplifier.
Its high voltage and current capability allows it to drive both low and high-impedance Hi-Fi headphones.
Connecting headphones automatically mutes the balanced and unbalanced preamplifier outputs.
Rega recommends reducing the volume before inserting or removing headphones to protect both the headphones and the listener.
- Up to 2.5W into a 33-ohm load
- Up to 0.5W into a 240-ohm load
- High-voltage and high-current discrete design
- Automatic preamplifier-output muting
- DC and over-current protection
Full-Colour IPS Display
The front-panel IPS display provides clear information about the selected input, digital sample rate, DAC filter, DSD mode, volume, mute state, record function and protection status.
The backlight uses a linear DC supply to reduce the possibility of display-related noise entering the audio circuitry.
Display behaviour can be set to Always On, 30 seconds or 5 seconds. Backlight level can also be adjusted through the menu.
Orbit Reference Remote Control
The custom Orbit reference remote control is supplied with the Mercury.
Its backlit controls provide access to:
- Volume adjustment
- Input selection
- Mute
- On and standby
- Mercury and Solis system power
- Record monitoring
- DAC filter selection
- Display settings
- Automatic standby settings
- AV bypass settings
- DSD mode
- 12V trigger settings
- Display backlight adjustment
A screwdriver and two AAA batteries are supplied for the Orbit handset.
Standby and 12V Trigger Control
The Mercury includes front-panel and remote-controlled standby operation.
Automatic standby can be set to activate after 20 minutes, one hour or disabled entirely.
A 12V trigger input and output allow the Mercury to control or follow the power state of compatible equipment, including the Rega Solis.
Two trigger cables are included and compatible products can be connected in a daisy chain where required.
AV Bypass on Input 5
Input 5 can be configured as an AV bypass connection for integration with a home cinema receiver, processor or other product that provides its own controlled preamplifier output.
When bypass is active, the Mercury volume control is removed from the signal path and the incoming signal is sent directly to its preamplifier outputs.
The bypass function must be enabled through both the rear-panel switch and the Mercury menu. This dual-stage system helps prevent accidental activation.
Important AV Bypass Warning
Only connect a source with its own working volume control to Input 5 when AV bypass is enabled.
Connecting a fixed-level CD player, streamer or DAC while bypass is active could send maximum output directly to the power amplifier, potentially damaging the loudspeakers and the listener's hearing.
Record Input and Output
A dedicated record loop allows compatible cassette decks, digital recorders, sound cards and other recording equipment to be connected.
The Record output provides a buffered copy of the currently selected source. It remains at full level and is not affected by the Mercury volume control.
When Record monitoring is activated, the selected source continues to feed the Record output while the connected recorder's monitor signal is heard through the main preamplifier outputs.
Important Record Output Warning
Never connect the fixed-level Record output directly to a power amplifier or active loudspeaker without its own volume control.
The output is not controlled by the Mercury volume adjustment and could drive connected equipment at maximum level.
Protection and Supervisory Circuits
The Mercury includes comprehensive protection for its main outputs and headphone amplifier.
DC output levels are monitored continuously. If excessive direct current is detected, the outputs are muted within milliseconds and a protection warning appears on the display.
The headphone amplifier also includes over-current protection for unsuitable loads and abnormal operating conditions.
Slow-start and supervisory circuits manage the toroidal transformer during power-up, reducing initial inrush current.
The protection circuits, display, microcontroller and supervisory system have their own power supply, helping to isolate them from the audio stages.
Installation and Positioning
The Mercury weighs 14kg and must be placed on a strong, level equipment support rated to carry its weight.
Adequate airflow should be maintained around the case, particularly beneath the unit where some heat is dispersed.
Do not place another component directly above or below the Mercury. An equipment rack with separate shelves is recommended.
To reduce the possibility of magnetic interference or hum, position the Mercury away from turntables, phono stages and large power amplifier transformers as far as the available cables reasonably allow.
Rega recommends arranging components beside one another rather than stacking them.
What the Mercury Does Not Include
No Power Amplifier
- Cannot drive passive loudspeakers directly
- Requires a separate power amplifier
- Rega Solis is the intended partner
No Phono Stage
- No moving magnet phono input
- No moving coil phono input
- Requires an external phono stage for turntables
No Network Streaming
- No Wi-Fi
- No Ethernet connection
- No streaming-service apps
- No Bluetooth
- Requires a separate network streamer
No HDMI Connection
- No HDMI ARC or eARC
- Televisions connect through optical audio
- TV output must be set to two-channel PCM
Who Is the Rega Mercury For?
A Good Choice If You:
- Are building a reference separate preamplifier and power amplifier system
- Want Rega's matching Solis power amplifier
- Use several analogue and digital sources
- Want balanced and unbalanced connectivity
- Need coaxial, optical and asynchronous USB inputs
- Want DSD64 playback through USB
- Use high-quality low or high-impedance headphones
- Need AV bypass and a record loop
- Want a full-colour display and comprehensive remote control
- Value long-term system flexibility and upgrade potential
Consider Another Option If You:
- Need an integrated power amplifier for passive speakers
- Want a built-in moving magnet or moving coil phono stage
- Need built-in network streaming
- Want Bluetooth or wireless multiroom playback without another source
- Need HDMI ARC or eARC
- Want a compact or lightweight pre-amplifier
- Do not have suitable space for separate preamplifier and power amplifier components
- Cannot provide a strong equipment rack and adequate ventilation
Key Features
- Reference-level analogue pre-amplifier
- Fully discrete symmetrical core signal path
- Common-base voltage amplifier circuitry
- Complementary Class A output stages
- Linear Systems ultra-low-noise FET transistors
- Alps Blue Velvet RK27 motorised volume control
- Generously rated toroidal transformer
- Discrete symmetrical tracking power supply
- One balanced XLR analogue input
- Four unbalanced RCA analogue inputs
- Separate Record input and fixed-level output
- Balanced XLR preamplifier output
- Unbalanced RCA preamplifier output
- AV bypass available through Input 5
- Two coaxial S/PDIF digital inputs
- Two optical Toslink digital inputs
- Galvanically isolated asynchronous USB input
- PCM support up to 32-bit/192kHz through USB
- PCM support up to 24-bit/192kHz through S/PDIF
- DSD64 playback through USB using DoP
- Two parallel-connected Wolfson DACs
- Five selectable PCM digital filters
- DSD Direct and DSD Plus modes
- High-current discrete headphone amplifier
- Full-colour IPS display
- Adjustable display duration and backlight
- Custom backlit Orbit reference remote control
- 20-minute, one-hour or disabled auto standby
- 12V trigger input and output
- DC, over-current and output protection
- Custom CNC-machined aluminium case
- Rega Couple 3 interconnect supplied
- Two trigger cables supplied
- Rega Reference mains lead supplied
- Lifetime limited warranty against confirmed manufacturing defects
Included Accessories
- Rega Mercury Reference Pre-Amplifier
- Custom backlit Orbit reference remote control
- Two AAA remote-control batteries
- Remote-control battery-compartment screwdriver
- Rega Couple 3 interconnect
- Two 12V trigger cables
- Rega Reference mains lead
- User documentation
Frequently Asked Questions
Is the Rega Mercury an integrated amplifier?
No. It is a pre-amplifier and cannot drive passive loudspeakers directly. A separate power amplifier, such as the Rega Solis, is required.
Which power amplifier is designed for the Mercury?
The Rega Solis Reference Stereo Power Amplifier was developed as the Mercury's matching power amplifier.
Is a power amplifier cable supplied?
Yes. A Rega Couple 3 interconnect is supplied along with two 12V trigger cables.
Does the Mercury have a built-in DAC?
Yes. It uses two parallel-connected Wolfson DACs and includes two coaxial, two optical and one asynchronous USB input.
What digital resolutions are supported?
The coaxial and optical inputs support PCM up to 24-bit/192kHz. USB supports PCM up to 32-bit/192kHz and DSD64 through DoP.
Does it support DSD?
Yes. DSD64 is supported through the asynchronous USB input using DoP. DSD is not supported through the coaxial or optical inputs.
Does the Mercury include USB-C?
No. It uses a USB 2.0 Type-B input. A suitable cable or adaptor may be required depending on the connected computer or mobile device.
Can I connect a television?
Yes. A compatible television can connect through an optical input. Set the television to output two-channel PCM or LPCM rather than Dolby Digital or DTS.
Does it have HDMI ARC or eARC?
No. Television sound is connected through optical or coaxial digital audio.
Does it include network streaming?
No. A separate network streamer such as a WiiM Ultra, Bluesound Node Icon or another compatible source is required.
Can I connect a WiiM streamer?
Yes. Connect a compatible WiiM model through its coaxial, optical or analogue output. Use a fixed output setting when the Mercury is controlling system volume.
Can I connect a Bluesound streamer?
Yes. A Bluesound Node or Node Icon can connect digitally or through its analogue outputs. Set the streamer to fixed output when using the Mercury volume control.
Does the Mercury include a phono stage?
No. A turntable requires a separate moving magnet or moving coil phono stage connected to one of the analogue line inputs.
Can I connect the Rega Aura?
Yes. The Aura Reference MC can connect through the balanced XLR input or one of the unbalanced RCA inputs.
How many analogue inputs are provided?
There is one balanced XLR input and four unbalanced RCA line inputs, plus a separate Record input.
Should I use balanced or unbalanced connections?
Rega recommends unbalanced RCA connections between the Mercury and Solis for optimum sound quality in most domestic installations. Balanced connections may be useful with compatible equipment or long cable runs.
Does it include a headphone amplifier?
Yes. The Mercury includes a powerful discrete headphone amplifier designed for both low and high-impedance Hi-Fi headphones.
What happens when headphones are connected?
The balanced and unbalanced preamplifier outputs are automatically muted.
What is AV bypass?
AV bypass allows Input 5 to accept a volume-controlled signal from an AV receiver or processor while bypassing the Mercury volume control.
Can I connect a CD player to Input 5 in bypass mode?
No. A fixed-level source connected while bypass is active could drive the power amplifier and speakers at maximum output.
Does it have a record output?
Yes. The fixed-level Record output provides a buffered copy of the selected source and is unaffected by the Mercury volume control.
Can the Record output connect directly to the Solis?
No. The Record output is fixed at full level and must never be connected directly to a power amplifier.
Does it have automatic standby?
Yes. Automatic standby can be set to 20 minutes, one hour or disabled.
Can it switch the Solis on and off?
Yes. The supplied 12V trigger cables and Orbit remote allow compatible Mercury and Solis system-power operation.
How much ventilation does it require?
Leave open space around the case and do not stack other equipment directly above or below it. The supporting shelf must also be strong enough for its 14kg weight.
Can I arrange a demonstration?
Yes. Contact your local Audio T store to arrange a demonstration of the Mercury with the Solis and suitable reference source components and loudspeakers.
Why Buy From Audio T?
- Specialist advice from experienced in-store teams
- Demonstrations with the matching Rega Solis power amplifier
- Help matching the Mercury and Solis with suitable loudspeakers
- Reference turntable, cartridge and phono-stage advice
- Streamer, CD player and digital-source comparison
- Balanced and unbalanced connection guidance
- AV bypass, record loop and 12V trigger setup support
- Headphone matching advice
- Home demonstrations may be available depending on location and system requirements
- Part exchange available on suitable equipment
- Ongoing support from the UK's oldest independent specialist Hi-Fi retailer
Contact your local Audio T store
to arrange a demonstration or discuss whether the Rega Mercury Reference Pre-Amplifier is right for your system.