The
improvements that have been taking place in turntables, CD players, and
loudspeakers demand a new level of performance from the amplifier - the heart
of every hi-fi system. The discerning buyer expects that today's amplifier
should combine a natural yet dynamic and powerful sound quality with good looks
and ease of operation. above all, the amplifier's standard of manufacture and
quality control should promise years of consistent, trouble free performance.
Until now,
only a handful of designs were able to meet all of these stringent criteria.
Unfortunately the prices of amplifiers in this select group often made them
incceassible to those on a limited budget. Arcam, recognising this unfulfilled
demand, has now designed and produced a
modern, top quality amplifier that is truly affordable - the Arcam Alpha 2.
Offering
many of the sonic benefits of more expensive models, the Arcam Alpha 2 would be
regarded as a fine amplifier at any price. However, when its outstanding
performance, facilities and construction are compared with other amplifiers at
its price level, it is clear that the Alpha 2 is destined to become a classic,
setting the new standards by which all others will be judged.
Philosophy
The Arcam
Alpha 2 is a product of Arcam's many years of experience in amplifier design
and manufacture. Detailed theoretical analysis and extensive listening have
produced a design that is technically outstanding. This design has been
realised in practice using high quality components selected for optimum
electrical and sonic performance. The result is an amplifier that maintains the
full dynamics of a musical performance while reproducing the subtleties and
emotion both accurately and naturally.
Power
Not only
does the Alpha 2 produce a generous 30 watts continuous output per channel into
8 ohms, but its special high peak
current output stage will drive loudspeakers whose impedance dips as low as 2
ohms. Unlike many other amplifiers the Alpha 2 can be run continuously at high
levels because its coolrunning aluminium chassis will not overheat.
Versatility
As well as
working properly with all commonly available loudspeakers, the Arcam Aplha 2 is
fully compatible with a wide variety of programme sources. Five inputs are
available; four are selected by a rotaty switch and the fifth by the nearby
tape monitor button. all the inputs use a high quality and robust design of
phono socket.
The Alpha
2's cartridge input is specialy optimised for use with any moving magnet
cartridge or high output moving coil cartridge. The highest quality low output
moving coil cartridges can also be accommodated using our optional plug in MCA
pre-pre-amplifier board.
There is a
dedicated input for a CD player, further inputs for a Tuner and Video playback
and finally a set of line level input and output sockets suitable for use with
a tape recorder.
Fexibility
A quality
domestic hi-fi amplifier can and should possess those genuinely useful
facilities which can improve the performance of the complete system. Typical of
Arcam's attention to detail is the Alpha 2' volume control which has been
psychoacoustically designed to allow ease of adjustment at the low volume
levels often used in the home. limited range bass and treble controls of
advanced design are also provided. These allow precise adjustment of the
frequency extremes without coloration of the critical midfrequency band. Used
sensibly they can help correct for imperfections elsewhere in the system,
particularly those associated with cartridges and loudspeakers. The constant
power law balance control also helps in this respect. The tone and balance controls
all have a centre click stop to provide a reference response in the centre
position.
The Alpha 2
has a front pabel socket which will suit a wide variety of stereo headphones.
The headphones and loudspeakers will normally work together as the main
loudspeaker sockets are wired directly to the amplifier's output to obtainthe
best possible sound quality. However a
second pair of loudspeaker socket is also fitted enabling the loudspeakers to
be muted automatically whenever headphones are plugged in.
Electronic
Design
The disc
pre-amplifier uses a low noise professional IC and employs audiophile grade 1%
metal film resistors and polypropylene capacitors in the critical RIAA
equalisation network. This ensures a clean, accurate sound.
Uniguely the
Alpha2 is also configurated to accept out plug in moving coil cartridge
pre-pre-amplifier board, the MCA. The MCA and Alpha 2 combination has a much
lower noise level and correspondingly greater fidelity than other similarly
priced amplifiers. This allows the Alpha 2 to be used successfully with some of
the world's finest MC cartridges.
All other
inputs are fed directly to the Alpha 2's volume control to ensure a virtually
infinite overload margin. The preamplifier stages which follow the volume
control again employ low noise professional quality ICs and make minimal use of
coupling capacitors to avoid degradation of the sudio signal. All preamplifier
circuits are powered by two lownoise, low-impedance regulated power supplies.
The Arcam
Alpha 2's power amplifier is an advanced bipolar, high slew-rate design with
direct coupled fully complementary class AB output stages. Constant bias
circuitry for the driver transistors maintains a clean, dynamic output
throughout the entire operating range. The amplifier has a very high transient
current capability, made possible by use of 100 watt power transistors combined
with high value low ESR reservoir capacitors and a generously rated toroidal
mains transformer. Together these permit instantaneous peak output levels of
some 250 watts from a single channel into a 2 ohm load. Nevertheless the
amplifier is effectively protected against overload. readily accessible
fast-blow output fuses are also fitted for loudspeaker protection. They are
connected within the main feedback loop
to prevent degradation of the signal. In addition the layout of the PCB has
been optimised for such factors as maximum transient power capability and
minimum on-board interaction.
Finally, the
loudspeaker outputs use ultra high quality PCB mounted 4 mm sockets. These
employ silver loaded contacts amd are soldered directly to the PCB to ensure
integrity of the signal path. High quality matching plugs are supplied as
standard.
Specifications
Output
Power:
30 W - both channels into 8 ohm (20 Hz - 20 kHz at
0,5%THD)
40 W - single channel at 1 khz into 8 ohm
60 W - single channel at 1 khzinto 8 ohm
Total
Harmonic Distortion: 0,02% (at 25 W into
8 Ω at 1 kHz)
Overload
Margins:
Disc Inputs
: 32 dB at 1 kHz
Other Inputs
: 50 dB
Frequency
Response:
Disc Input
: 60 HZ - 20 kHz , ±0,5 dB, -3 dB at 20
Hz
Other Inputs
: 30 Hz - 20 kHz ±0,5 dB, -1 dB at 20 Hz
Tone
Controls:
Bass : +-8 dB at 50 Hz
Treble
: +-8 dB at 15 kHz
crosstalk: -65 dB at 1 kHz
Disc Inputs:
Suitable for
MM and high-output MC cartridges
Sensitivity
: 2,5 mV
Noise : -72 dB
impedance
: 47 k Ω
in parallel with 100 pF
With MCA
board fitted, for low output MC cartridges
Sensitivity 250 µV
Noise : -70 dB
Impedance
: 330 Ω
Tuner, TApe,
Video :
Sensitivity
: 200 mV
Noise : -95 dB
Impedance
: 25 k Ω
CD
Sensitivity
: 450 mV
Noise : -95 dB
Impedance
: 10 k Ω
Outputs
Nominal Level/Impedance
Tape : 220 mV/2 k Ω
Headphones
: suitable for 8 Ω - 2 k Ω
impedance
Loudspeaker: 30 W into 8 Ω
at 1 kHz
low
frequency daming Factor : 200
Suitable for
speaker of 4 Ω or higher nominal
impedance
General
Power
Supply: 240 V , 110 V ; 50/60 kHz
Power
Consumption : 120 VA
Spares
Provided
Two
loudspeaker fuses;
Two red and
two black 4 mm plugs
Dimensions
(W x H x D): 430 x 230 x 84 mm
(16,9" x 9,1" x 3,3")
