The AR
amplifier will provide any speaker system with a signal source as accurate and
powerful as is ever likely to be needed in the home. In addition, the AR
amplifier offers the reliabilty and moderate price which are the objectives of
every AR design. The result is a unit
which uses advanced silicon transistor technology and manufacturing and testing
techniques developed by AR to achieve a level of performance comparable to or
exceeding, that of the best professional recording or broadcast equipment of
its type. This is shown in the technical data sheet published by AR,
corroborated by independent tests such as that by CBS laboratories published in
High Fidelity, and guaranteed by AR to remain correct .
One of the
most important characteristics of an amplifier is its power output. Consumers
might therefore expect this measurement to be presented clearly and accurately
in amplifier advertising. This has not been the case. In recent years, a
variety of vague and irrelevant terms has been used by manufactures to describe
power output; music power, transisor power, IHF power and others. The list
includes terms invented by manufactures and applied to their products alone, as
well as standards of measurement known only to advertising copy writers. In a
recent issue of High Fidelity for example, 18 manufacturers advertised
amplifiers, but in only two casas were power ratings referred to a known
standard.
Acoustic
Research accepts the definition of a watt given in physics texts; work done at
the rate of 0,7375 ft-lb/second. We know of no "music watt" or
"IHF watt" which science tecognizes. AR amplifiers are rated exactly
as we measure them, with both channels continuously delivering at least the
rated power without exceeding our harmonic distortion limit of 0,5% or our IM
distortion limit of 0,25%. The laws of physics and the nature of music require
that power measurements, if they are to be meaningful, be made with a steady,
uninterruptedtone, similar to the purest means. AR amplifiers must deliver
their rated continous power at all frequencies to which the ear responds, non
just at 1,000 Hz, where most amplifiers
can deliver much more power than at the extremes ofthe ramge of hearing.
Distortion measurements are made through the AR amplifier's phono input because
this is the way music goes through the amplifier - even though performance
might be better with the preamplifier out of the circuit.
For these
reasons, the power output rating of the AR amplifier is true for any kind of
musical tone, not only those easy for an amplifier to reproduce, whether the
source is an FM broadcast a tape recording or a phonograpf record.
The
workmanship and performance in normal use of the AR amplifier are guaranted for
two years from the date of purchase.
AR publishes
a non-technical guide for consumers who want to know the basic facts about
amplifiers, what they do and how they differ from each other. It is entitled,
"You Don't Have To Be An Engineer", and is available free on request.
Specifications
Power
Output:
60
watts per channel RMS at 4 Ω
50
watts per channel RMS at 8 Ω
30
watts per channel RMS at 16 Ω
Rated with
both channels running at full output at 0,5% THD or less, at any frequency
between 20 and 20,000 Hz.
Harmonic
Distortion: less than 0,5% from 20 -
20,000 Hz
IM
Distortion (60 & 7,000 Hz , 4:1):
less than 0,25% at any listening level to full power.
Frequency
Response: 20 Hz to 20,000 Hz ±1 dB
(indicated flat tone control settings, at full power or below)
Switched
Input Circuits: Magnetic Phono; Tuner;
Tape Playback
Outputs: Tape record; 4 - 16 Ω speakers
Input
Sensitivity/ Impedance:
Phono
: 2 mV - 5 mV/50 k Ω
Tape
PB, Tuner : 200 mV/150 k Ω
Signal-to-Noise
Ratio:
Phono : 57 dB
Tape Pb,
Tuner : 75 dB
Output
Impedance Tape Record: 5 k Ω
Output
Impedance at Speaker Terminals: 0,2 to
0,5 Ω (depending on frequency)
Damping
Factor:
8 to
20 for 4 Ω speakers
16 to
40 for 8 Ω speakers
32 to
80 for 16 Ω speakers
Safety
Features: Line fuse; speaker fuses;
Circuit breakers (self-resetting)
Circuit
Characteristics:
DC Driver
clamping for clean overload recovery;
Idling power
supply eliminates turn-on transient noises;
Bass and
treble separately controlled for each channel;
Differential
loudness compensation curves in bass control circuit;
Special null
circuit permits exact balancing of stereo source material;
Stable under
short-circuit of speaker terminals;
Built-in
null circuit provides quick accurate means for channel balancing;
Color coded
input and output conectors simplify installation,.
Power
Input: 110 - 220 volts AC, 50/60 Hz
Dimensions
(H x W x D): 4-5/16" x 15-1/2"
x 10" (without cover); 4-1/2"
x 15-3/4" x 10" (with wood cover)
Weight: 19 lbs (8,64 kg)