Editing Tag McLaren 700:7R

The 700:7r is a high-performance seven-channel 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, or can be instantly switched to give five channels of 100W and one channel of 150W, or three channels of 100W and two channels of 150W. 

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. 

The 700:7r includes comprehensive but completely unobtrusive protection against overload, excessively prolonged clipping, DC offsets, and high temperatures.

Technology 

An Optimal Mix of Feedback
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 rapidly-changing signals. The 700:7r design is implemented by giving each amplifying stage controlled amounts of local feedback, which 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 a carefully chosen amount of negative feedback is applied. 

Cascode Compensation
The 700:7r uses an advanced loop stabilisation concept called Cascode Compensation. Its advantages are: 
- Excellent stability 
- Inherently good supply-rail rejection
- Reduction of DC drift 

Bipolar Output Devices
The output devices are bipolar junction transistors chosen for maximum linearity in terms of sustained current gain at high collector currents. 

Exceptional Quiescent Stability
It is universally accepted that accurate setting and stability of quiescent conditions is crucial to optimal operation. The 700:7r has extremely accurate quiescent control with quiescent conditions stabilised against:
- Output level & load impedance
- Mains voltage 

Comprehensive protection
The 700:7r has sophisticated 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. 

Sophisticated muting
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 distortion
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 amplifiers have a frequency response which extends both above and below the range of normal human hearing. 

Straight line technology
An amplifier must respond to very low frequencies but block any Direct Current (DC) to prevent intermodulation distortion. This is traditionally achieved using capacitors, which also block some of the low-frequency signals. In the 700:7r a feedback circuit eliminates DC offset voltage and allows the signal path to be direct coupled without any capacitors, an arrangement called ‘straight line’ technology. 

Supersonic frequency response
In order to reproduce high frequencies, the 700:7r is constructed using highly-rated, high-precision components. The circuit has been painstakingly designed to minimise audio signals picking up interference and intermodulating. Exceptional transparency and purity of sound are the result. 

mixed technology construction
With surface mount components for fast digital signal transfer and leaded through-hole components for perfect audio signals, the 700:7r incorporates mixed technology construction to optimise performance. 
Ample Power 

The 700:7r contains 7 pairs of loudspeaker terminals. 

For seven channel applications set the CHANNEL BRIDGING switch to the OFF position. 

Seven speakers can now be connected normally between the seven red + and black - terminals. 

Each channel is fed with a maximum of 100 Watt into 8 Ohm. 


For six (five) channel applications set the CHANNEL BRIDGING switch to its BR+SR (BR+SL|BL+SL) position. 

For six or five channel operation you can bridge two amplifier channels for greater power output. 

In this mode three channels remain at a maximum of 100 Watt into 8 Ohm whilst two bridged channels now offer powerful 150 Watt into 8 Ohm. 

Convenient Operation 

Connect the mains cable to the 700:7r and its blue power LED will glow dimly to indicate that power is applied but the amplifier remains in its standby state. 

In this condition the loudspeakers are disconnected by the internal muting relays and power is removed from the amplifier circuitry. 

The 700:7r remains in standby until it receives either an audio signal of sufficient magnitude or a signal is fed to its Contact Closure switch. 

The 700:7r indicates its active mode by its blue power LED glowing brightly. 

The amplifier will remain active for 15 minutes after all audio signals disappear and will then return to standby. This delay period is to prevent the amplifier going to standby on brief interruptions, eg while changing CDs. 

Audio signal activation 

Set the STANDBY MODE switch to the “ALWAYS ON” position and the 700:7r will remain ‘on’ at all time. 

Set the STANDBY MODE switch to the “NORMAL” position and the amplifier will remain in standby until it receives an audio signal of sufficient amplitude. 

Set the STANDBY SWITCH to “SENSITIVITY LOW” if you want the 700:7r to switch only on if a louder audio signal is received. 


Contact closure activation 

If an AV processor providing a contact closure is connected, e.g. a TAG McLaren AV processor with action-switches, then Contact Closure will always bring the amplifier into the active mode, whatever the position of the standby mode switch on the rear. 


The contact closure is applied to the 700:7r via the 3.5mm jack socket on the rear panel.