OPERATION
When the amplifier is connected to the mains the LED immediately above the power switch will indicate red
(standby). When switched on, this LED will change to illuminate green (operational). There will be a delay of about
12 seconds before the output signal is fed to the loudspeakers, this is to allow the amplifier to stabilise.
In the event of a major overload or a short circuit across the output of any channel, the green "power on" LED will
indicate trip by fading and immediately re-illuminating to red standby mode. The amplifier will shut down
automatically and it should then be switched off. When the fault condition has been rectified, the amplifier can be
switched on and will power up as normal. A minimum period of eight seconds must be allowed to elapse between
switching off and switching on again. This is to allow the power supply protection circuitry to re-set itself.
There are no user serviceable parts in your SPM 650. It should only be serviced by Chord Electronics Limited or their
expressly approved Service Agents.
CARE AND CLEANING
The SPM 650 requires no special care other than common-sense. Spray window cleaner (clear type) may be used (if
first sprayed on to a soft cloth) to remove surface blemishes such as finger marks from the metal casing. Never spray
directly on to the amplifier and never use abrasive cleaning materials, use only a lint free soft cloth as described.
SERVICE INFORMATION
WARNING - The power supply components within this amplifier are designed to be operated at lethal voltages and
energy levels. Circuit designs that embody these components conform with applicable safety requirements.
Precautions must be taken to prevent accidental contact with power-line potentials. Do not connect grounded test
equipment.
NEW TECHNOLOGY
Much of what Chord has achieved is the result of using innovative, leading edge technology. For example, we believe
that we are unique in using the technique of ‘dynamic coupling’ of the power supply rails. Whatever transient
demand is presented to the amplifier stages, the positive and negative rails remain in perfect equilibrium, with each
compensating for the demands made on the other. This means that power delivery is always balanced and free from
ground loop modulation distortion.
This, combined with enormous reserves of instantly delivered, precisely controlled power is what makes the SPM 650
sound so effortless. The power supply rails operate well above that which most amplifiers can accommodate. This
and other advanced techniques enables the ultra high frequency low ESR power supply to store a great deal more
energy far more efficiently. Clipping is virtually impossible. Furthermore, compared to other amplifiers of a similar
power rating the SPM 650 weighs in at a mere 9Kg. Another new technique is used to protect the amplifier against
overload, internal and external short circuits. The output signal path is totally free of any fuses or sound-degrading
resistive components often employed for overload sensing. The SPM 650 is designed to surpass the highest European
safety and electromagnetic interference standards.
The amplifier sections are also highly sophisticated designs that make the most of the best high voltage, lateral
structure MOSFETs available, 2 x 300 watt devices per channel. Combining the subtlety and musicality of a good
valve design with the punch and accuracy of ‘state of the art’ solid state products. The result is a ‘sliding bias’ class
A/B design with all drive circuitry operating in class A. At usual listening levels, most of the music will be
reproduced in class A. Chord’s no-compromise design philosophy means there is no better built amplifier.
Individually hand-crafted, it is constructed to aerospace standards from the circuit boards up.
