Rega Isis Reference CD Player

The Rega Isis is the flagship CD player within Rega's Reference range.

Its substantial custom-designed enclosure is machined from solid aluminium and finished with a black chrome front fascia and manual top-loading lid.

The standard solid-state version weighs 19kg, while the Valve Isis weighs 19.5kg. Both require a strong equipment support and sufficient space above the case for the lid to open fully.

Rather than relying on a conventional off-the-shelf CD control system, Rega developed its own disc operating technology, servo control, digital signal processing and error-correction system.

The Isis is also equipped with RCA and balanced XLR analogue outputs, coaxial and optical digital outputs and a USB input that allows its internal DAC to be used with a compatible computer.

Choose Your Rega Isis Version

The Rega Isis is available with either a solid-state or valve-based analogue output stage.

Select your preferred version from the available product options. Audio T can arrange a comparison between the solid-state Isis and Valve Isis where demonstration stock is available.

Solid-State Isis Analogue Stage

The solid-state Isis uses two Burr Brown PCM1794 DACs operating in parallel dual-mono mode.

The current output from each converter is passed to a high-performance discrete Class A current-to-voltage amplifier rather than a conventional integrated operational amplifier.

This approach allowed Rega to optimise the conversion and analogue filtering circuits specifically for the player rather than accepting the fixed characteristics of a standard integrated output stage.

The signal then passes through an enhanced discrete Class A output amplifier.

The circuit is fully balanced from the outputs of the DACs to the balanced XLR connections.

• Two Burr Brown PCM1794 DACs
• Parallel dual-mono conversion
• Discrete Class A current-to-voltage amplification
• Discrete Class A output amplification
• Fully balanced path to the XLR outputs
• Wide dynamic range and low distortion

Valve Isis Analogue Stage

The Valve Isis was developed to use valves as an integral part of a carefully engineered analogue circuit rather than simply placing a valve buffer after a conventional solid-state CD player.

The differential outputs from the twin Wolfson DACs drive two military-specification triple-mica 5814A valves.

A solid-state current generator is used within the differential amplifier to stabilise its operating conditions while maintaining a relatively modest amount of feedback.

The signal then passes through a passive second-order Butterworth LC filter before reaching two low-anode-resistance ECC88 valves used as output buffers and transformer drivers.

Rega specifies typical total harmonic distortion of approximately 0.06 per cent, with predominantly even-order harmonic content.

• Two military-specification 5814A valves
• Two ECC88 output-buffer valves
• Solid-state differential-stage current generator
• Passive second-order Butterworth LC filter
• Transformer-driven balanced output
• Fully regulated high-voltage and low-voltage valve supplies

Valve Isis Digital Filters

A three-position switch on the rear panel of the Valve Isis provides a choice of digital-filter responses.

There is no universally correct filter setting. The preferred option may depend on the recording, partnering system and personal listening preference.

Valve Warm-Up and Power-On Delay

The Valve Isis mutes its analogue outputs for approximately 30 seconds after switch-on while the valves begin warming and the signal capacitors stabilise.

A disc can be loaded and initialised during this period, but no analogue output will be available until the mute relay activates.

Rega advises that the valves take approximately five minutes to reach their normal operating temperature.

Rega Disc Operating Technology

Rega developed a dedicated disc operating system rather than relying entirely on a standard third-party CD chipset.

Its control architecture includes substantial onboard memory and 32-bit digital signal processing to manage data retrieval, servo control and error correction.

Rega's own phase-locked-loop arrangement controls the digital clocking and is intended to improve the quality and stability of the data delivered to the DAC section.

Separate attention has been paid to the optical amplifier, master clock, motor supplies, digital processing and user-interface circuitry.

Individual Disc Analysis

The Isis analyses each disc during initialisation and adjusts its reading system to suit the physical characteristics of that particular CD.

This can improve the player's ability to read discs with minor marks or scratches that may cause difficulties for some conventional players.

The system cannot compensate for every damaged or incorrectly manufactured disc. Discs that do not meet the correct Red Book standard, including some poor-quality copied discs, may still fail to play.

Graded and Matched Laser Mechanism

The CD mechanism is graded and matched to its servo circuitry during production.

Rega individually selects, measures and optimises the laser assembly to help the optical and servo amplifiers operate within their intended range.

A three-point ball-chuck system holds the disc in place while keeping the rotating mass of the puck relatively low.

The mechanism is manually top loaded, avoiding the additional motors, belts and moving components required by a conventional disc drawer.

Archived Replacement Laser Mechanisms

During production, Rega matches three laser mechanisms to each Isis.

One mechanism is installed in the player, while two additional matched assemblies are marked with the product serial number and archived at the Rega factory.

If the original mechanism later requires replacement, an archived assembly can be supplied through an authorised Rega retailer or distributor.

Rega states that it takes reasonable steps to store these assemblies safely, although storage remains subject to circumstances outside the manufacturer's control.

Separate Analogue and Digital Power Supplies

The Isis uses separate power transformers for its analogue and digital sections.

In the solid-state version, the analogue stage has a dedicated 50VA transformer and ten separate power-supply regulators.

The digital section has another dedicated 50VA transformer and a further ten regulators.

The motor, display and user-interface processor also receive dedicated supplies, helping to isolate them from the more sensitive conversion and analogue circuits.

The Valve Isis retains separate analogue and digital supply arrangements while adding fully regulated high-voltage and heater supplies for its valve stage.

Custom Rega Power-Supply Components

Rega K-Power smoothing capacitors and fast-recovery rectifier diodes are used throughout the power supplies.

Solid-polymer capacitors help maintain low power-supply impedance around the digital-to-analogue converters.

Critical electrolytic capacitors are bypassed with polypropylene or polyester film capacitors where appropriate.

Large-value electrolytic capacitors are also bypassed with selected audio-grade electrolytic components.

RCA Analogue Outputs

Both Isis versions provide a conventional stereo RCA analogue output for connection to an integrated amplifier or pre-amplifier.

The supplied Rega Couple interconnect can be used to connect the player to a suitable line-level input marked CD, AUX, Line or similar.

The RCA outputs should never be connected to a moving magnet or moving coil phono input.

On the solid-state Isis, the RCA output level is 2.2V with a source impedance of 560 ohms.

Balanced XLR Outputs

Balanced XLR outputs are also provided for connection to suitably equipped amplifiers and pre-amplifiers.

The solid-state Isis maintains a fully balanced signal path from its DACs to the XLR outputs.

The Valve Isis uses output transformers to provide galvanically isolated balanced connections.

On the solid-state version, the XLR output level is 4.4V with a source impedance of 560 ohms.

Where an amplifier provides both RCA and XLR inputs, we recommend comparing both connections rather than assuming that one will always give better results.

Coaxial and Optical Digital Outputs

The Isis can also operate as a dedicated CD transport with an external DAC or compatible digital pre-amplifier.

Coaxial RCA and optical Toslink digital outputs are provided.

These connections carry the digital signal from the CD transport to an external converter.

USB DAC Input

A USB Type-B input allows a compatible computer to use the digital-to-analogue converter inside the Isis.

The USB interface is galvanically isolated and uses its own regulated supply, helping prevent computer earth currents and power-supply noise from entering the player.

It supports 16-bit audio at 44.1kHz and 48kHz.

This is a legacy USB audio connection and does not support modern high-resolution formats such as 24-bit/192kHz PCM or DSD.

A USB Type-A to Type-B cable is required and is not supplied.

Adding Reference Music Streaming

The Isis does not contain network-streaming functionality and its coaxial and optical connections are digital outputs rather than inputs.

A reference music streamer should therefore be treated as a separate source within the wider system. It would normally connect to another input on the partnering integrated amplifier or pre-amplifier, or to a suitable external DAC.

This allows the Isis to remain the dedicated source for physical CDs while the streamer provides access to online services, internet radio and locally stored music.

The best streamer, output module and connection method will depend on the amplifier, pre-amplifier and DAC used within the system. Audio T can arrange comparative demonstrations and advise on the most appropriate configuration.

Connecting the Isis to the Rega Mercury

The Rega Mercury Reference Pre-Amplifier can accept the analogue output from the Isis through either an RCA or compatible balanced XLR connection.

Alternatively, the Isis coaxial or optical output can connect to a digital input on the Mercury, allowing the Mercury DAC to perform conversion.

Comparing the Isis analogue output with the Mercury DAC can help determine which conversion and output stage best suits the complete system.

A Naim NSS 333, Innuos STREAM1 or Innuos STREAM3 can also connect separately to the Mercury, allowing the pre-amplifier to control both physical CD playback and network streaming within the same reference system.

Connecting the Isis to a Rega Amplifier

Manual Top-Loading Design

The Isis uses a manual top-loading mechanism rather than a motorised drawer.

Lift the lid, place the CD over the spindle and fit the supplied disc puck before closing the lid.

A manual mechanism avoids the additional motors, belts and gears required by a powered loading tray.

The player requires a total operating height of approximately 200mm so that the lid and disc aperture remain accessible.

Disc and File Compatibility

The Isis is primarily designed for standard Red Book audio CDs.

Its control system can also support compatible MP3 and WMA media, although compatibility may depend on the disc, file structure and recording method.

The USB input can play compatible 16-bit audio from a computer at 44.1kHz or 48kHz.

The Isis is not an SACD, DVD-Audio, Blu-ray or network-streaming player.

Reference Remote Control

A substantial CNC-machined Rega reference remote control is supplied.

It provides access to the standard CD playback functions, including:

• Play and pause
• Stop
• Previous and next track
• Forward and reverse search
• Repeat
• Shuffle
• Track programming
• Time display
• Display on or off
• USB input selection
• Compatible MP3 and WMA navigation

Two AAA batteries are supplied.

Switchable Display

The front-panel display can be switched off using the remote control.

This reduces unnecessary illumination during listening and may also reduce low-level electrical noise from the display circuitry.

Installation and Equipment Support

The solid-state Isis weighs 19kg and the Valve Isis weighs 19.5kg.

Place the player on a firm, level shelf rated to support its weight.

A top shelf is often the most practical position because the player requires access from above and a total operating height of approximately 200mm.

Do not position the player where the open lid could strike another shelf or piece of equipment.

Allow ventilation around the case, particularly when using the Valve Isis, and avoid stacking other equipment directly on top.

Care and Handling

Handle CDs by their outer edges and return them to their cases when not in use.

Do not touch or attempt to clean the laser lens inside the player.

Keep the lid closed when the player is not in use to reduce the possibility of dust reaching the mechanism.

If an object falls inside the player, switch it off, disconnect it from the mains and contact an authorised Rega retailer.

What the Rega Isis Does Not Include

Who Is the Rega Isis For?

Key Features

• Available as the solid-state Isis or Valve Isis
• Rega reference top-loading CD mechanism
• Rega-developed disc operating technology
• Individual disc analysis and optimised error correction
• Graded and servo-matched laser mechanism
• Two additional matched laser mechanisms archived at Rega
• Manual top-loading lid and disc puck
• Custom CNC-machined anodised aluminium enclosure
• Black chrome front fascia and lid
• Separate analogue and digital power transformers
• Rega K-Power smoothing capacitors
• Fast-recovery rectifier diodes
• Solid-polymer DAC power-supply capacitors
• RCA analogue outputs
• Balanced XLR analogue outputs
• Coaxial digital output
• Optical Toslink digital output
• Galvanically isolated USB Type-B input
• USB support for 16-bit audio at 44.1kHz and 48kHz
• Switchable front-panel display
• CNC-machined Rega reference remote control
• Rega Couple interconnect supplied
• High-current Rega mains lead supplied
• Lifetime limited warranty against confirmed manufacturing defects

Included Accessories

Frequently Asked Questions