Audio T Verdict
The Rega Solis is a reference stereo power amplifier designed for systems that require substantial power, strong current delivery and the additional separation provided by dedicated pre-amplifier and power-amplifier components.
It delivers 168W per channel into 8 ohms and 305W per channel into 4 ohms, supported by two custom 330VA toroidal transformers, 40,000µF of smoothing capacitance per channel and twelve high-current Sanken output transistors.
The Rega Mercury is its ideal partner, although the Solis can also be used with the variable preamplifier output of the Rega Aethos or another suitable pre-amplifier. At this level, careful loudspeaker matching and a proper demonstration are essential.
Rega Solis Reference Stereo Power Amplifier
The Rega Solis is a dedicated stereo power amplifier and the culmination of almost four decades of Rega solid-state amplifier development.
It was developed alongside the Mercury Reference Pre-Amplifier, allowing sensitive low-voltage pre-amplifier circuitry and high-current power-amplifier circuitry to operate within separate enclosures.
This physical separation can reduce electrical and magnetic interaction between the two sections while allowing each product to use a dedicated power supply and internal layout.
The Solis contains no input selector or volume control. Its purpose is to take the controlled output from a compatible pre-amplifier and provide the current and voltage required to drive passive loudspeakers.
What Does a Power Amplifier Do?
A power amplifier receives a volume-controlled signal from a pre-amplifier and increases it to the level required by passive loudspeakers.
The pre-amplifier handles source selection and listening volume, while the power amplifier supplies the energy required to control the loudspeaker drive units.
The Solis must therefore be partnered with a compatible pre-amplifier or another product with a properly controlled variable preamplifier output.
Important Connection Warning
Never connect a CD player, streamer, DAC, phono stage or other conventional fixed-level source directly to the Solis.
The Solis has no internal volume control. A fixed-level source would drive the amplifier at or close to maximum output, potentially causing loudspeaker damage and hearing damage.
168W Per Channel into 8 Ohms
The Solis delivers 168W RMS per channel into an 8-ohm loudspeaker load.
Output rises to 305W RMS per channel into 4 ohms, demonstrating the substantial current reserves provided by the amplifier and its dual power supplies.
This makes the Solis suitable for consideration with a wide range of high-performance standmount and floorstanding loudspeakers, including designs with more demanding impedance behaviour.
- 168W RMS per channel into 8 ohms
- 305W RMS per channel into 4 ohms
- Both channels driven
- Power amplifier gain of 33.3dB
- Speaker compatibility from 4 to 16 ohms
- Substantial current delivery for demanding musical peaks
Fully Symmetrical Discrete Amplifier Circuit
The Solis uses fully symmetrical discrete circuitry throughout the main power-amplifier signal path.
A differentially driven common-base voltage-amplifier stage provides high linearity, wide bandwidth and the voltage swing required by the output section.
The cascoded differential input amplifier uses two low-noise LED-referenced current generators.
Rega has carefully selected the open-loop and closed-loop feedback levels and gain-bandwidth components to maintain stability, control and low distortion.
- Fully discrete power-amplifier circuit
- Fully symmetrical internal topology
- Differentially driven common-base voltage amplifier
- Cascoded differential input stage
- Low-noise LED-referenced current generators
- Optimised open-loop and closed-loop feedback
- DC-coupled loudspeaker outputs
Twelve High-Current Sanken Output Transistors
Twelve Sanken 130W, 15A high-frequency multi-emitter output transistors are used within the Solis.
Six devices are allocated to each channel in a triple high-current output-stage arrangement.
This provides the output section with the current capability required to maintain control during demanding musical passages and when loudspeaker impedance falls.
HTR non-inductive resistors are used within the output stage to minimise unwanted inductive behaviour.
Carefully Selected Signal-Path Components
Rega has selected components according to their electrical and sonic properties rather than relying on specification figures alone.
ICEL polypropylene capacitors, HTR non-inductive resistors and high-quality relays are used within the signal path.
Nichicon audio-grade capacitors are used in critical bypass and decoupling positions.
Electrolytic capacitors are bypassed with polyester capacitors where appropriate to improve high-frequency behaviour.
- ICEL polypropylene signal capacitors
- HTR non-inductive output-stage resistors
- Nichicon audio-grade capacitors
- High-quality signal relays
- Polyester bypass capacitors where required
- Surface-mount technology developed through Rega amplifier production
Two Custom 330VA Toroidal Transformers
The Solis uses two low-noise, custom-designed 330VA toroidal transformers.
Each channel is supported by its own transformer, contributing to the amplifier's dual-mono power-supply arrangement.
High-grade fully bonded core material is used to reduce mechanical transformer noise under difficult mains conditions.
Microcontroller-controlled slow-start circuitry manages the initial inrush current when the two transformers are powered.
80,000µF Total Smoothing Capacitance
Each amplifier channel has 40,000µF of Rega K-Power smoothing capacitance, providing 80,000µF across the complete stereo amplifier.
This stored energy supports the output stage during sudden dynamic peaks and contributes to the Solis ability to increase its output substantially into a 4-ohm load.
Fast-recovery rectifier diodes are used throughout the power supplies to reduce high-frequency switching noise and provide a cleaner DC supply.
Regulated Low-Noise Driver Supplies
The input and low-level driver stages are supplied by regulated symmetrical tracking power supplies.
Low-noise voltage references provide stable supply rails for the sensitive amplification stages.
Dedicated audio power supplies feed only the audio circuits, while the control, protection and supervisory electronics use a separate galvanically isolated supply.
This separation helps prevent the microcontroller, standby system and protection circuits from introducing noise into the main audio path.
Designed for the Rega Mercury
The
Rega Mercury Reference Pre-Amplifier
is the Solis ideal system partner.
The Mercury provides analogue and digital source selection, volume control, a high-performance DAC, discrete headphone amplifier, AV bypass, record loop and balanced and unbalanced preamplifier outputs.
Separating the Mercury low-level circuitry from the transformers and high-current output stages inside the Solis allows both products to concentrate on their individual roles.
The included Couple 3 interconnect and trigger cables allow the two products to be connected and controlled as a coordinated system.
Using the Rega Aethos as a Pre-Amplifier
The
Rega Aethos
can also be used as a pre-amplifier for the Solis.
The Aethos variable RCA preamplifier output connects to the Solis unbalanced input, with source selection and volume controlled by the Aethos.
This provides an upgrade route for existing Aethos owners who require additional power or want to explore separate power amplification without immediately replacing their source-control component.
The loudspeakers should be connected to the Solis rather than to the Aethos when the Solis is being used as the main power amplifier.
Compatible with Other Preamplifiers
The Solis can be used with another suitably designed pre-amplifier provided its output level, impedance and connection type are compatible.
The pre-amplifier must provide a reliable variable output controlled by its volume adjustment.
Audio T can check electrical compatibility and arrange a demonstration where the Solis is being considered for an existing system.
Balanced and Unbalanced Inputs
The Solis provides one balanced stereo XLR input and one unbalanced stereo RCA input.
A rear-panel switch selects which connection is active, with an indicator confirming balanced or unbalanced operation.
Although connecting cables to both inputs simultaneously will not damage the amplifier, Rega does not recommend doing so.
Unbalanced RCA Input
The unbalanced input has a sensitivity of 820mV and an input impedance of 35 kilohms.
Rega recommends this connection between the Mercury and Solis for optimum sound quality in most domestic systems.
Balanced XLR Input
The balanced input has a sensitivity of 1.64V and an input impedance of 26 kilohms.
It may be useful with a compatible pre-amplifier, professional equipment or installations requiring longer interconnects.
Symmetrical Circuitry and Balanced Connections
The term symmetrical describes the internal amplifier circuit and should not be confused with a fully balanced input-to-output signal topology.
The core Mercury and Solis audio circuits are unbalanced. Additional circuitry is therefore required to convert the balanced XLR input signal.
Balanced connections can reject noise picked up over long cable runs, which is why they are common in recording studios and professional sound systems.
In a typical domestic system using short interconnects, this noise-rejection advantage may not be required. Rega therefore recommends the unbalanced connection between the Mercury and Solis under normal domestic conditions.
Audio T can arrange a balanced and unbalanced comparison where the partnering pre-amplifier supports both connection methods.
Independent Mute Control
A front-panel Mute button temporarily disables the loudspeaker outputs without switching the amplifier into standby.
The Mute function can also be controlled using the Rega Orbit reference remote, which is supplied with the Mercury and available separately.
A front-panel indicator confirms when mute is active.
Standby and Automatic Standby
The Solis includes a standby mode that can be controlled from its front panel, through a compatible 12V trigger connection or with the Orbit reference system remote.
When automatic standby is enabled, the amplifier enters standby after approximately one hour without an input signal.
Automatic standby can be disabled where required, although doing so increases energy consumption.
Power consumption in standby is approximately 0.4W.
12V Trigger Input and Output
A 12V trigger input allows the Solis to follow the power state of a compatible pre-amplifier or system controller.
The trigger output can pass the control signal to another compatible product, allowing several components to be linked in a daisy chain.
For complete Mercury and Solis system control, Rega recommends connecting both the trigger input and output.
Two compatible trigger cables are supplied with the Solis.
Warm-Up and Playback Optimisation
After leaving standby, the Solis reaches its optimum idle operating condition after approximately 60 minutes.
This warm-up period can be shortened by playing music through the amplifier.
The amplifier can still be used immediately after completing its startup and protection checks.
Speaker Matching
The Solis loudspeaker outputs are intended for passive speakers with an impedance between 4 and 16 ohms.
Its 168W output into 8 ohms and 305W into 4 ohms provide considerable headroom for a wide range of standmount and floorstanding designs.
Power output alone does not guarantee an ideal match. Loudspeaker sensitivity, minimum impedance, electrical phase, room size and preferred listening level should also be considered.
Sustained high-level use with loudspeakers below 6 ohms may cause the Solis to run considerably warmer and could activate its thermal protection.
At this system level, we strongly recommend hearing the amplifier with your intended loudspeakers and familiar recordings.
Reference Vinyl System
The Solis can form part of a complete Rega reference vinyl system when partnered with the Mercury, an external phono stage and a suitably capable turntable.
Rega Naia and Aura
The
Rega Naia
with Aphelion 2 cartridge and
Rega Aura Reference MC
creates Rega's flagship production vinyl source.
The Aura connects to the Mercury, which then controls the signal sent to the Solis.
Rega Planar 10
The
Rega Planar 10
with Apheta 3 or Aphelion 2 is another natural source for a Mercury and Solis system.
A compatible moving coil phono stage is required between the turntable and Mercury.
Adding Reference Network Streaming
The Solis does not contain a DAC or network streamer. Streaming sources connect to the Mercury or another compatible pre-amplifier rather than directly to the power amplifier.
In a reference-level Mercury and Solis system, a high-performance streamer such as the Naim NSS 333, Innuos Stream1 or Innuos Stream3 provides a more appropriately matched digital source.
Naim NSS 333
The
Naim NSS 333
is a high-performance network streamer and digital-to-analogue converter designed for premium separates systems.
Its analogue output can connect to the Mercury through a suitable RCA or balanced XLR input, allowing the NSS 333 to operate as a complete streaming source alongside the Mercury and Solis.
Where both connection types are available, Audio T can arrange a comparison between the RCA and balanced outputs.
Innuos Stream1
The
Innuos Stream1
is a modular music streamer and server that can be configured around the requirements of the wider system.
Depending on the selected output module, it can operate as a digital transport feeding the Mercury DAC or provide an analogue output for connection to one of the Mercury line inputs.
Optional internal storage also allows the Stream1 to manage a locally stored music library alongside online streaming services.
Innuos Stream3
The
Innuos Stream3
is the higher-performance model in the Innuos Stream range and is designed as the foundation of a reference digital source.
Its modular architecture allows it to be configured as a high-quality streaming transport and music server or as a complete analogue source with a suitable DAC output module.
It can therefore feed the Mercury digitally or connect through an analogue line input, depending on the chosen configuration.
When an analogue streamer output is connected to the Mercury and the Mercury is controlling system volume, the streamer should normally be configured for fixed output.
The best streamer, output module and connection method will depend on the complete system. Audio T can arrange comparative demonstrations and advise on the most appropriate Naim or Innuos configuration.
Protection Systems
The Solis includes comprehensive protection for both the amplifier and connected loudspeakers.
Thermal Protection
If the internal temperature becomes potentially damaging, the amplifier first mutes the loudspeaker outputs.
If the unit does not cool sufficiently within approximately five minutes, it switches itself off.
The amplifier should then be left off for at least ten minutes before restarting.
DC Protection
The loudspeaker outputs are DC coupled to reduce the number of capacitors within the signal path.
If excessive direct current is detected, the protection circuit disables the outputs within milliseconds.
Short-Circuit Protection
Foldback protection limits excessive current if the speaker cables are accidentally shorted.
Rega positions this protection outside the principal audio signal path.
Installation and Ventilation
The Solis weighs 24.8kg and requires a strong, stable and level equipment support.
Heat is dissipated through the substantial heatsinks positioned along both side panels.
Both side sections must remain exposed with sufficient open space for air to circulate.
The heatsinks can become very hot and should not be touched during or shortly after extended operation.
Never place the amplifier on carpet, rugs, fabric or bedding, and do not stack other Hi-Fi equipment directly on top.
The recommended ambient operating temperature is between 5 and 35 degrees Celsius.
Position turntables and sensitive phono stages as far away from the Solis transformers as the available interconnects reasonably allow.
Solis, Osiris or Aethos?
Rega Aethos
The
Rega Aethos
is an integrated amplifier delivering 125W per channel into 8 ohms.
It includes source selection, volume control, headphone output and a variable preamplifier output within one case.
It is the more compact and affordable choice when a separate Mercury pre-amplifier is not required.
Rega Osiris
The
Rega Osiris
is Rega's traditional flagship integrated amplifier.
It delivers 162W per channel into 8 ohms and includes passive volume control, source selection, one balanced input and four RCA inputs.
It is the choice for customers who want a high-power reference amplifier within one enclosure.
Rega Mercury and Solis
The Mercury and Solis divide the low-level pre-amplifier and high-current power-amplifier sections into separate enclosures.
The combination adds the Mercury DAC, headphone amplifier, display, AV bypass, record loop, extensive digital connectivity and system control.
It also provides slightly higher rated power than the Osiris, particularly into a 4-ohm load.
What the Rega Solis Does Not Include
No Volume Control
- Requires a compatible pre-amplifier
- Cannot accept a fixed-level source directly
- No source-selection controls
No Phono Stage
- No moving magnet phono input
- No moving coil phono input
- Turntables connect through a phono stage and pre-amplifier
No Digital or Streaming Features
- No built-in DAC
- No optical or coaxial input
- No USB input
- No network streaming
- No Bluetooth
- No HDMI
No Headphone or Subwoofer Output
- No headphone socket
- No preamplifier output
- No dedicated subwoofer output
- Subwoofers connect through the pre-amplifier or suitable high-level connections
Who Is the Rega Solis For?
A Good Choice If You:
- Want a reference stereo power amplifier
- Already own or plan to buy the Rega Mercury
- Own a Rega Aethos and want a higher-powered external amplifier
- Use high-performance passive loudspeakers
- Need substantial current delivery into 4-ohm loads
- Want balanced and unbalanced input options
- Want standby, automatic standby and 12V trigger control
- Value separate pre-amplifier and power-amplifier construction
- Have a strong equipment rack and suitable ventilation
Consider Another Option If You:
- Need an integrated amplifier with volume control
- Want to connect a streamer or CD player directly
- Need a built-in moving magnet or moving coil phono stage
- Need built-in digital inputs or streaming
- Want a headphone output
- Need a compact or lightweight amplifier
- Cannot leave both side heatsinks exposed
- Use active loudspeakers that do not require external power amplification
Key Features
- 168W RMS per channel into 8 ohms
- 305W RMS per channel into 4 ohms
- Dedicated reference stereo power amplifier
- Fully symmetrical discrete power-amplifier circuitry
- Differentially driven common-base voltage amplifier
- Cascoded differential input stage
- Twelve Sanken 130W, 15A output transistors
- Six output transistors per channel
- Triple high-current output-stage arrangement
- Two custom-designed 330VA toroidal transformers
- 40,000µF of Rega K-Power smoothing capacitance per channel
- Fast-recovery rectifier diodes
- Regulated symmetrical low-noise driver-stage supplies
- ICEL polypropylene signal capacitors
- Nichicon audio-grade capacitors
- HTR non-inductive output-stage resistors
- Balanced XLR input
- Unbalanced RCA input
- Rear-panel balanced and unbalanced selector
- Independent front-panel mute function
- User-selectable automatic standby
- 12V trigger input and output
- Microcontroller-controlled slow start
- Thermal protection
- DC protection
- Foldback short-circuit protection
- Custom aluminium case and side heatsinks
- Reference mains lead supplied
- Rega Couple 3 interconnect supplied
- Two 12V trigger cables supplied
- Lifetime limited warranty against confirmed manufacturing defects
Included Accessories
- Rega Solis Reference Stereo Power Amplifier
- Rega Reference mains lead
- Rega Couple 3 interconnect
- Two 12V trigger cables
- User documentation
Frequently Asked Questions
Is the Rega Solis an integrated amplifier?
No. It is a dedicated power amplifier and requires a compatible pre-amplifier to select sources and control volume.
How powerful is the Rega Solis?
The Solis delivers 168W RMS per channel into 8 ohms and 305W RMS per channel into 4 ohms.
Which pre-amplifier is designed for the Solis?
The Rega Mercury Reference Pre-Amplifier is the matching pre-amplifier and was developed alongside the Solis.
Can I use another pre-amplifier?
Yes, provided it has a compatible variable preamplifier output and suitable electrical characteristics. Audio T can check compatibility before connection.
Can the Rega Aethos control the Solis?
Yes. The variable RCA preamplifier output on the Aethos can connect to the Solis unbalanced input.
Can I connect a streamer directly to the Solis?
No. The Solis has no volume control, so a conventional fixed-level streamer could drive the amplifier at maximum level. A Naim NSS 333, Innuos Stream1, Innuos Stream3 or another streaming source must connect through the Mercury or another suitable pre-amplifier.
Can I connect a CD player directly?
No. A CD player must connect to a compatible pre-amplifier unless it has a properly configured variable output and is specifically suitable for direct power-amplifier connection.
Does the Solis have a built-in DAC?
No. Digital sources connect through the DAC inside the Mercury, a streamer, CD player or separate digital-to-analogue converter.
Does it include network streaming or Bluetooth?
No. Streaming functionality must be provided by a separate source connected to the pre-amplifier.
Which streamers are suitable for a Mercury and Solis system?
Suitable reference-level options include the Naim NSS 333 and the modular Innuos Stream1 and Stream3. The best choice depends on whether you want a complete streamer and DAC, a digital transport, local music storage or a modular upgrade path.
Can I connect a Naim NSS 333 to the Mercury?
Yes. The NSS 333 can connect to a suitable analogue input on the Mercury. Use fixed output when the Mercury is controlling system volume.
Can I use an Innuos Stream1 or Stream3?
Yes. Depending on the selected output module, an Innuos Stream1 or Stream3 can connect digitally to the Mercury DAC or through an analogue line input.
Does it include a phono stage?
No. A turntable requires a separate phono stage connected to the Mercury or another suitable pre-amplifier.
Should I use balanced or unbalanced connections?
Rega recommends the unbalanced RCA connection between the Mercury and Solis for most domestic systems. Balanced XLR may be useful with other compatible equipment or longer cable runs.
Can both input types remain connected?
Connecting both will not normally damage the amplifier, but Rega does not recommend it. Use the rear-panel switch to select the required input.
Does the Solis have a volume control?
No. Listening volume is controlled by the connected pre-amplifier.
Does it have a headphone socket?
No. The matching Mercury includes a dedicated discrete headphone amplifier.
Can I connect an active subwoofer?
A subwoofer should normally connect to the pre-amplifier or use suitable high-level connections. The Solis does not include a dedicated subwoofer output.
What speaker impedance is supported?
Rega specifies passive loudspeakers between 4 and 16 ohms.
Can it drive 4-ohm loudspeakers?
Yes. The Solis is rated at 305W per channel into 4 ohms. Extended high-level use with loads below 6 ohms may make the amplifier considerably warmer.
Does the Solis have automatic standby?
Yes. When enabled, it enters standby after approximately one hour without an input signal. The feature can be disabled.
Can the Mercury switch the Solis on and off?
Yes. The supplied 12V trigger cables allow coordinated power control between compatible Mercury and Solis components.
Is a remote control included?
A remote is not included specifically with the Solis. The compatible Orbit reference remote is supplied with the Mercury and can control Solis system power and mute.
How long does it take to warm up?
Rega states that the amplifier reaches its optimum idle operating condition after approximately 60 minutes. Playing music can shorten the warm-up period.
Does the Solis run hot?
The side heatsinks can become very hot, particularly during extended high-level use. Both sides must remain exposed with sufficient ventilation.
Can other equipment be stacked on top?
No. Stacking can obstruct cooling and place sensitive components too close to the power transformers.
How strong must the equipment rack be?
The support must safely carry the Solis 24.8kg weight and remain stable once the mains lead, interconnects and speaker cables are attached.
Can I arrange a demonstration?
Yes. Contact your local Audio T store to arrange a demonstration with the Mercury and suitable reference sources and loudspeakers.
Why Buy From Audio T?
- Specialist advice from experienced in-store teams
- Demonstrations with the matching Rega Mercury pre-amplifier
- Help matching the Solis with suitable loudspeakers
- Reference turntable, cartridge and phono-stage advice
- Reference streamer, DAC and CD-player system comparisons
- Help integrating Naim NSS 333 and Innuos Stream1 or Stream3 sources
- Guidance on Innuos output modules, storage and connection options
- Balanced and unbalanced connection guidance
- 12V trigger and system-control setup support
- Advice on ventilation, equipment supports and installation
- 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 Solis Reference Stereo Power Amplifier is right for your system.