The Arcam
Delta 70 compact disc player has been designed to provide the best possible
sound quality from compact disc digital audio. Together with the Arcam Delta
90, Delta 80 and the range of Arcam loudspeakers, the Delta 70 makes up the
first complete CD based hi-fi system to be both designed and manufactured in
great britain.
Design
Philosophy
Most
specialist hi-fi companies merely "badge engineer" or modify mass
produced Cd players, and are restricted to using their normal plastic chassis
and standard circuit boards. From the outset, A&R Cambridge limited
realised that this approach was simply not good enough to produce a Cd player
to the standard demanded of an Arcam product. A&R therefore went to the
trouble and expense of procuring full CD manufacturing licence. This gave our
designers the opportunity to engineer the Delta 70 to a superior mechanical and
electronic standard, incorporating much of the experience gained in producing
some of the world's most acclaimed hi-fi amplifiers. Consequently, not only
does the Delta 70 sound better, it is also visually more appealing and much
easier to use than other CD players on the market.
Versatility
Careful
ergonomic design has simplified the operation of the Delta 70 to the extend
that anyone can play a compact disc on it within a few seconds of first
encountering the player. This is in marked contrast to many otherwise admirable
CD players, whose complex control layout and over-elaborate displays frequently
give rise to continued 'technofear', even amongst the most experienced users,
let alone normal music lovers.
The controls
on the front panel of the Delta 70 are divided into two groups. On the upper
level they comprise just those needed to load, play and stop a compact disc.
One the lower level we have included the pause button (conveniently located
directly underneath the main stop button) and all the commonly needed
programming functions. These include 3 speed search facilities and the previous
and next track selection buttons, which will also access index points within a
track. An easy to program memory is provided; this is capable of memorising the
order of play of up to 20 different tracks.
To make
operations even easier and more convenient the Delta 70 can be remote
controlled using our optional infra-red remote control handset.
The displays
on the Delta 70 have also been kept deliberately simple. An attractive and easy
to read 4 digit fluorescent display provides readout of track and index
numbers. It can also be used to indicate the total playing time of the disc and
the elapsed time of each track as it is played.
Typical of
the care and attention that our designers have taken is the location of the
status indicator LEDs, which are provided for the power pause, and time/track
functions. These are located just where they are needed, above the appropriate
buttons, rather than buried elsewhere on the fascia.
Flexibility
The Delta
70's audio outputs are comprehensive, with both direct and variable outputs
being provided. The latter is controlled via a low impedance ALPS potentiometer
and is designed to feed a high quality power amplifier directly without the
loss of quality associated with a conventional preamplifier. A headphones
socket with adjustable output level is also included. This is driven from its
own high quality amplifier, which has sufficient gain and power to drive almost
any pair of moving coil headphones. Finally a digital output socket is fitted,
for use with outboard D/A systems and for futur applictaions such as CD-ROM and
CD-I.
Electronic Design
To recover
as much information from the disc as possible the Delta 70 uses a swing arm
single-beam laser pickup. This produces an inherently accurate signal from the
disc than the 3-beam system used in most players. The disc playing mechanism is
mounted on a fully floating sub-chassis to isolate it from external vibration.
Allied to this is a 64K DRAM-based adaptive error correction system, which is
one of the most comprehensive ever employed in a domestic Cd player. Taken
together these features ensure the greatest possible integrity of recovered
digital signal.
The digital
signal is then processed using twin linear phase 120 element finite impulse
response digital filters. These ultra stable low noise filters keep the audio
band remerkably flat but dramatically attenuate the unwanted h.f. components of
the audio signal. They are followed by dual 16 bit prcision DACs, operating in
the classic four times oversampling mode at a frequency of 176,4 kHz. To
enhance their timing linearity (and
hence sound quality) the Dacs are fed from a unique. A&R designed precision
master oscillator.
Great care
has been taken with all aspects of teh DAC and post-DAC filter and output
circuitry to preserve this hard-won sound quality. Audiophile quality
components been used throughout these stages, which have been assigned no less
than five fully stabilised, critically decoupled power supplies. Integral withh
the output filter which removes unwanted digital 'hash'. The circuitry is of an
all-discrete transistor, direct coupled, class A design, which totally
eliminates sound degrading interstage coupling capacitors from the signal path.
Specifications
Playback
System: 16 bit , 4 x oversampling, dual
DACs and class A direct coupled, discrete transistor analogue filter and output
stages.
Optical
Read-out System:
Laser Type :
Semiconductor Al Ga As
Numerical
Aperture : 0,45
Wavelenght :
800 nm
Typical
Audio performance (20 Hz - 20 kHz unless otherwise stated)
Frequency
Response: 10 Hz - 10 kHz ±0,1 dB, -0,6 dB at 20 kHz
Channel
Balance: ±0,1 dB
Channel
Phase balance ± 0,5 deg
THD: 0,007% at 1 kHz, 0 dB
Signal-to-Noise
ratio: 101 dB unweighted; 105 dB
CCIR/ARM weighted
Dynamic
Range: 96 dB
Channel
Separation: 100 dB at 1 kHz
Wow and
Flutter: Quartz precision control
Direct
Outputs Level/Impedance: 2V RMS at MSB
(0dB)/120 Ω
Miniumu
Load Impedance: 5 k Ω
Variable
Output Level/Impedance: 2V RMS, max at
MSB (0dB)/1,25 k Ω max.
Headphone
Output level/Impedance: 7V RMS max. At MSB (0dB)/ 250 Ω
Power
Supply: 110, 120 220, 240 V AC 50/60 Hz
Power
Consumption: 25 Watts
Dimensions
(W x H x D): 430 x 90 x 270 mm
Weight: 4,5 kg net