Tag mclaren audio 700X7R User Manual
ow ner ’s manual
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0 4 i n t r o d u c t i o n
0 5 t e c h n o l o g y
0 9 set up
1 5 o p e r a t i o n
1 7 prote ction s ystem
1 9 running in and warming up
2 0 care and mainte nance
2 1 technical data
c o n t e n t s
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c o n t r o l s
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The 700:7r is designed for the simplest possible operation, and the
only controls are two mode switches on the rear panel. One sets the
standby mode and the other the channel bridging. Details of these
are given on pages 11 and 15.
Sp ecifi catio n sho wn m ay va ry for d if fere nt c ountr ies
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i n t r o d u c t i o n
5, 6 or 7 speaker system? All are catered for by the 700:7r.
The seven channels could be assigned as:
The 700:7r is a high-performance sevenchannel amplifier that delivers sound
reproduction of outstanding clarity and
purity together with the flexibility to handle a
wide range of home theatre applications.
The 700:7r provides seven channels of
100W into 8 Ohm (7.1 set-up), or can
be instantly switched to give five
channels of 100W and one channel of
150W (6.1 set-up), or three channels
of 100W and two channels of 150W
(5.1 set-up). For details see page 11.
Channel
Rear panel text
Power
Left
LEFT
100 W
Right
RIGHT
100 W
Centre
CENTRE
100 W
Surround Left
SL
100 W
Surround Right
SR
100 W
Back Left
BL
100 W
Back Right
BR
100 W
The amplifier switches itself to a standby mode when not in use, to minimise power
consumption. It returns from standby to active on receiving a signal input or external contact
closure; alternatively it can be set to stay permanently in the active mode. For details see
page 15.
The 700:7r includes comprehensive but completely unobtrusive protection against overload,
excessively prolonged clipping, DC offsets, and high temperatures.
t e c h n o l o g y
An Optimal Mix of Global and Local Negative Feedba c k
The 700:7r gives excellent linearity and low distortion without relying on excessive global
negative feedback, which can present difficulties with stability and the handling of rapidlychanging signals. The 700:7r design is implemented by giving each amplifying stage
controlled amounts of local feedback, which not only linearises it but also defines the gain
and other vital parameters closely. Each stage is thus configured for dependable and
predictable operation, so that when they are joined together to build a complete amplifier,
and a carefully chosen amount of negative feedback applied around it, the results are highly
dependable and predictable.
Cascode Compens ation
The 700:7r uses an advanced loop stabilisation concept called Cascode Compensation.
To the best of our knowledge TAG McLaren Audio is the only manufacturer to use this
sophisticated and elegant system in an audio amplifier.
Its advantages are as follows:
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Excellent stability. All
the active components
involved are operated
under circuit conditions
that maximise their
bandwidth. This results
in greater stability
when the negativefeedback loops are
closed.
Inherently good
supply-rail rejection.
Components that are
essential for powersupply filtering in a
conventional amplifier
are no longer
required, saving
weight and cost and
enhancing reliability.
Reduction of DC drift. In a normal highpower amplifier transistors in sensitive
parts of the circuitry get warm, which
means their characteristics vary depending on the air flow around them.
Variations in cooling can appear as DC
drift at the output. Cascode compensation transfers the heat dissipation to noncritical parts of the circuit and DC drift
is virtually eliminated.
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t e c h n o l o gy
The Output Dev i ce s
The output devices are bipolar junction transistors chosen for maximum linearity in terms of
sustained current gain at high collector currents. The advanced MT-200 package is used
which gives a greater area for heat transfer than the traditional TO3. This reduces junction
temperatures and further enhances reliability.
Exceptional Quies cent Stability
It is universally accepted that accurate setting and stability of quiescent conditions is crucial
to optimal Class-B operation. The bias range over which the best linearity is obtained is
narrow, and on either side of it crossover distortion increases markedly. This consists of highorder harmonics that are acknowledged by all as undesirable; it is therefore of the first
importance that an amplifier stays in its optimal bias range, despite the many varying
conditions it will face in operation.
The 700:7r has extremely accurate quiescent control. Quiescent conditions are stabilised
against:
Output level and load impedance changes
This is implemented by a unique sensing configuration that gives much faster and more
accurate assessment of output device junction temperatures than the conventional
methods.
Mains voltage changes
It is not widely known that changes in mains voltage can affect amplifier quiescent
conditions even if all of the small-signal and biasing circuitry is made immune to these
variations. The effect is subtle and complex, but is dealt with authoritatively by circuitry
unique to TAG McLaren Audio.
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C o m p rehensive pr o t e c t i o n
The 700:7r has sophisticated and
dependable protection for both its own
circuitry and connected loudspeakers.
An instantaneous overload protection
system monitors the current and voltage
conditions in the output devices and limits
power dissipation in critical circumstances.
If the excessive loading persists, an
intelligent long-term protection algorithm
disconnects the load to prevent excessive
thermal stress which can shorten
component life.
Soph isticated mut ing
The 700:7r has a sophisticated muting
system, which stops you hearing loud,
annoying switching noises and protects
both the amplifier and the loudspeakers.
Particular care has been taken to make
sure that the muting circuitry, when
switched off, doesn’t affect the sound
quality. For this purpose carefully selected
relays with minimal crosstalk between coil
and contacts have been used.
Low distor t i o n
A theoretically ideal amplifier reproduces
sound perfectly over an infinite range of
frequencies - starting from well below the
audible range and extending far above the
capabilities of human hearing. Although
sound outside the human hearing range of
approximately 20 Hz to 20 kHz cannot be
heard, it can significantly distort the quality
of music reproduction through an effect
which audio engineers call
‘intermodulation distortion’. This type of
distortion moves imperfections that
originate outside the hearing range back
into the audible frequencies. To minimise
this effect, TAG
McLaren Audio
amplifiers have
a frequency
response
which
extends
both above
and below
the range of
normal human
hearing.
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