User Manual

Analogue section
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.
Digital section
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.
Mechanism
A high quality graded mechanism has been used which incorporates a three point mounting
ball chuck. This has advantages over the magnetic puck type design. Firstly it presents the disc
as flat as is possible to the laser spot directly resulting in improved reading of the information
on the disc. Secondly the mass of the puck is lost completely giving the mechanism itself less
stress and better acceleration and braking performance.
Digital
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.
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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.
USB Input
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 it’s 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.
Disc Analysis
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. However if the disc does not meet correct red book specification
(such as a pirated disc or low quality high speed copies) then some discs may not be
recognised and may fail to play.
Lid design
Our proven manual top loading design remains in place of the common motorised tray loading
mechanisms. Such motorised mechanisms are vulnerable to wear and therefore an
unnecessary cause of unreliability.
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