Rega Reference products at Moorgate
Rega have a reputation for bringing out high value and high performance equipment. But one of the reasons they can do that is because these share R&D with Rega Reference products. So the money that breaks new ground in these reference products filters down into budget equipment.
We wanted to cast some light on the two products in the Rega reference range because they are often overlooked and they deserve so much more.
Isis Reference CD player.
Rega’s flagship CD player, the Isis,is a product manufactured to the highest achievable quality inside and out including Rega’s own unique CD technology, genuine black chrome lid and front facia and a custom solid anodised aluminium case weighing in at a notable 19kg! We hope you enjoy this very special CD player; we have spent a very long time creating it, drawing on our many years of experience in specialist hi-fi manufacturing.
Technology behind the design of the Isis
One important design goal was to take the current output, with no internal amplification within the D to A converter, and convert this to an analogue voltage, using discrete class A operational amplifiers and filters.
This circuit can then be optimised for sonic performance. (With most CD players the use of standard operational integrated circuits locks you into the sound of those particular integrated circuits, thus narrowing the scope for improvement). The class A current to voltage conversion amplifier, evolved out of the development of the first stage of the Rega Ios MC amplifier.
It shares identical demands of low noise, high drive capability and gain bandwidth required of the voltage to current amplifier. Careful choice has been made for every component in the digital and the analogue signal path to ensure the integrity of the signal.
The analogue and digital sections are bonded together using a substantial ground plane. It was found during the development of the player that adoption of RF ground plane techniques aided the sonic quality and therefore was included in the final design.
Careful design of the PCB’s ensures isolation of not just the digital and analogue sections, but also the motor, display and user interface processor. All sonically critical electrolytic capacitors have been by-passed with polypropylene or polyester film capacitors. In addition to this, large value electrolytic capacitors have also been by-passed with audio grade electrolytic capacitors.
Power supply impedances in the digital to analogue converter are kept very low by the use of solid polymer capacitors. All power supplies utilise custom Rega K-Power smoothing capacitors, along with fast diodes which have been used throughout in power supply rectification.
The Isis uses enhanced and optimised control code for the control of the CD processor and user display.This speeds up the initialisation process by means of a tighter control interface between the user micro and CD processor.
The analogue section employs two Burr Brown PCM1794 digital to analogue converters, running in a parallel dual mono mode, driving a high performance discrete class A current to voltage amplifier.
This combination generates an exceptionally wide dynamic range, low distortion, and linear signal. This drives an enhanced discrete Class A output amplifier. The circuit is fully balanced from the digital to analogue converters to the balanced analogue XLR outputs.
The analogue stage has its own dedicated 50VA mains transformer which ensures galvanic isolation between the digital and analogue sections of the player. You will find 10 separate power supply regulators are used in the analogue circuit and each individual amplifier stage has its own dedicated low noise voltage reference.
The digital section is blue printed and selected, with major improvements to the mechanism, optical amplifier, DSP core, PLL, master clock & motor power supplies. Another 10 separate power supply regulators are used in the digital circuit.
The motor, user interface processor & display also have their own power supply. The digital stage also has its own 50VA transformer again ensuring galvanic isolation. The mechanism is graded and matched to the servo circuits, to ensure the servo and optical amplifiers are working at their optimum point, improving error correction and playability.
The headroom of the optical amplifier has been improved by 10% by increasing the voltage in the power supply.
This revolutionary player has been five years in design. Rega, together with its design partners have pioneered a highly advanced servo controller that uses the latest signal processing techniques to ensure that the raw data that is recovered from the disc is of the very highest quality. Because our fully digital servo can use highly advanced algorithms, the laser spot is kept in the optimum position for data recovery in terms of focus, size and tracking.
Extra Error Correction
Previous chip-sets always made compromises on error correction. Formerly it was possible to have good jog resistance or better musical performance.
The Rega chip-set allows optimum musical performance and optimised jog /vibration resistance.
Super-stable phase lock loop
The entire IC is clocked via a very special PLL of our own design. This allows better CD data recovery as well as a big improvement in the quality of the data delivered to the DAC.
Low noise digital design
In the design of our CPU IC, we went to great lengths to ensure that the data and address bus noise was kept to an absolute minimum. This ensures the ground and signal connections to the DAC are as ‘clean’ as is possible.
Allowing direct connection to a laptop or PC via a USB A-B lead to stream internet radio, MP3 or WMA files directly from your computer via the high quality Isis internal DAC.
The USB input uses an isolated double-clocked USB interface, which permits the digital to analogue stage to be used with a computer USB interface and its own regulated power supply.
The USB benefits once again from galvanic isolation from the main circuitry of the Isis player which eliminates the flow of earth currents between the CD and host computer, and eliminate computer power supply noise.
The Isis will analyse each disc on an individual basis. During the initialising period (rather like the engine management system on a modern car which optimises the engine settings to temperature, fuel quality etc.), the Isis will adjust itself to each disc in order to give optimal trouble free reading.
For this reason the Isis will often play discs with marks or scratches that other players cannot read.
We hope that you enjoy this product as much as we have enjoyed creating it.
- Discrete Class A operational amplifiers and filters
- Optimised for sonic performance
- Low noise, high drive capability and gain bandwidth
- Careful design of the PCB’s
- MP3 and WMA media capabilities
- Audio grade electrolytic capacitors
- Solid Polymer capacitors
- Rega ‘K Power’ smoothing capacitors
- Enhanced and optimised control code
- Two Burr Brown PCM 1794 digital to analogue converters, running in parallel dual mono mode
- High performance discrete Class A current to voltage amplifier
- Wide dynamic range, low distortion
- 10 separate power supply regulators are used in both the analogue and digital circuits
- 50 VA transformer
- The mechanism is graded and matched to the servo circuits
- Rega custom designed and CNC machined aluminium case work
- High quality anodised finish
- Aesthetic black chrome facia and lid
- CNC machined matching remote control
- Dimensions W 434mm x D 350mm x H 112mm
- Dimension needed to operate W 434mm x D 350mm x H 200mm
- Weight 19Kg
Listening to the Rega Isis
The Isis stands up extremely well alongside the best CD players we’ve ever heard. It really is extremely solid and presents a musical soundstage with a hint of analogue and none of the harshness often associated with CD.
More info here!
High performance integrated that puts many pre-power combinations to shame!
The Osiris is the culmination of 32 years’ experience in solid-state amplifier development. A no compromise, super high performance, 162 Watts into 8 Ohms (250 Watt 4 Ohms), dual mono amplifier housed in a custom Rega CNC machined aluminium case. Designed around “minimalist” high gain power amplifier and “passive pre-amplifier” circuit topology, a passive volume control and a single stage of power amplification between the input and the speakers, the Osiris offers unrivalled performance and build quality.
All these features combine to create the supreme level of performance found in the Osiris and provide a perfect partner for our Isis CD player. We hope that you enjoy this product as much as we have enjoyed creating it.
The Osiris uses a low distortion high linearity and a bandwidth common base voltage amplifier driver stage. This type of symmetrical circuit topology will provide the necessary voltage swings to enable the Osiris to drive any speaker system with the minimum of distortion. Eight Sanken 200 Watt output transistors are used in a “triple” high current output stage enabling the Osiris to drive even the most awkward of speaker systems with ease. The cascoded differential input amplifier uses two low noise LED referenced current generators. The open & closed loop feedback levels and gain bandwidth product components are optimised to give a tight and controlled sound stage, especially at the low frequency end of the audio range. Nichicon audio grade capacitors are used in bypass and de-coupling positions. Electrolytic capacitors have been bypassed with polyester capacitors where necessary, improving on the HF performance. Low inductance film SM power resistors are used in the output stage.
The Osiris uses two low noise, purpose designed 400VA toroidal transformers using high-grade, fully bonded core material. The transformers are mounted to the chassis using Rega’s innovative mounting technique which eliminates noise being transferred from the transformer to the case when the transformers are operating under arduous mains (line) conditions with high levels of asymmetric mains (line) distortion.
These transformers combined with 40,000 Micro Farads of Rega K-Power smoothing capacitors per channel, provide more than enough current to drive the hardest of loads. All the power supplies utilise fast recovery rectifier diodes throughout. (Fast diodes generate less high frequency switching noise therefore giving rise to a cleaner DC).
The input and low-level driver stages are fed from a regulated symmetrical tracking power supply with a low noise voltage reference, which provides a fully stabilised low noise voltage, ensuring the highest level of sonic purity. All the dedicated audio power supplies feed only the audio circuits. The input switching, display & micro controller and protection circuits have their own dedicated supplies, keeping the audio signal path as pure as possible.
- Thermal cut out
- Electronic thermal DC protection
- Short Circuit Protection
- Galvanically isolated power supply
- Nichicon Audio Grade Capacitors
- Cascoded differential input
- Direct Input
- High Specification mains lead
- Custom aluminium Osiris remote control
Specifications at 160w into 8Ω
- Power output 162 Watts per channel RMS
- Input sensitivity for 160 Watts into 8Ω 250 Watts into 4Ω
- Amplifier gain: Direct input 44dB
- Record output 215mV into 100K
- Frequency Response 10Hz (-1.7dB point)
- THD + Noise Less than 0.05%
- Power consumption 560W at 115/230V
- Dimensions: W 434mm x D 350mm x H 122mm
- Weight 25.6kgs
More info here!
The Isis and Osiris really do offer a superb combination that has a low box count but gives nothing away in terms of sound quality. They are both on permanent demonstration.