Free Audio Service Manuals - Free download Onkyo A 7040 Owners Manual

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Features

Installation and Handling

Super Servo Circuit

The unique Super Servo Circuit developed by Onkyo is
important for two very good reasons a (1) elimination of
unwanted ultra-low frequency components, and (2) ef-
fective improvement of the low end transient response which
tends to deteriorate in DC amplifier circuits.

Besides a normal negative feedback loop for the main signal,
this circuit also consists of a low frequency amplifier, and a
servo loop coupled to a phase inverter, resulting in active
feedback of the ultra~low frequency components. The out-
put impedance is consequently reduced for the very low
frequencies, the circuit operating just as if the output circuit
were shunted for these frequencies.

The Super Servo Circuit thus suppresses unwanted ultra-low
frequency components arising in the amplifier itself, and also
checks the flow back of counterelectromotive forces applied
from the speakers back to the amplifier, resulting in extreme-
ly stable amplifier operation.

The Onkyo Super Servo Circuit is thus quite unlike other
system where low frequency signals are cut by using an out-
put transformer or output capacitors. Unwanted ultra-low
frequency components are effectively removed without run-
ning into phase problems, or involving deterioration in the
quality of sound due to core magnet saturation distortion, or
instability due to application of excessive negative feedback.
The A-7040 consequently also features a very big improve-
ment in transient response in the low frequency region.

Output
40

Input
0 \

Main signal NFB
e-

lnverter Ultra»low

frequency NFB

Servo amplifier

Electronic Output Power Display

With 5 LEDs for each channel (a total of 10 for both chan-
nels), output power levels are displayed instantaneously and
very accurately, and also very attractively.

More power than youre ever likely to need

280 watts of total dynamic music power - a practically
inexhaustible power reservoir that lets you reproduce the
full splendor of orchestral or high level rock music with all
its original dynamics. The A-7040 produces 55 watts

per channel into 8 ohms, both channels driven at 1 kHz,
and with no more than an inaudible 0.026% of total har»
monic distortion. Onkyo gives you a lot of power - and
advanced Onkyo circuit engineering makes sure that it's all
clean power.

To ensure many years of trouble- free operation, keep the
following points in mind when setting up the A- 7040:

Avoid direct sunlight and other places subject to ex-
tremely high and low temperatu res. Also keep away
from heating appliances.

Do not block up the ventilation vents in any way.
Leaving the A-7040 in damp (or humid) and dusty places
for any length of time will also result in loss of perform-
ance.

If placed on a shelf or desk, it must be flat and sturdy,
and resistant to vibration. Also avoid placing the ampli-
fier in high places from which it may fall.

Do not place flower vases or other water-filled recepta-
cles on top of the A7040, since water spillage can cause
serious damage.

Useful to Know

Speaker Protection Fuses

To protect your valuable speakers from possible damage
through excessive power or an amplifier malfunction, each
speaker is protected by a special fuse. These are located
under the cover marked SPEAKER FUSE on the rear panel.
If the fuse should burn out and you hear no sound at all
from the speakers, remove the cover with a Phillips head
screwdriver and replace the fuse(s) with identical 4A types.
Voltage Selector

Before turning on the power supply for the first time,
ALWAYS check that the selected rating (and corresponding
fuse) agrees with your local AC mains rating. If not, unscrew
the central fuse cover, readjust appropriately, and replace the
fuse (4A for 110/120V, 3A for 220/240V).

Note:

Note that models not equipped with a voltage selector can
only be used in localities whose voltage rating agrees with
that of the A-7040 indicated on the rear panel.

Cleaning the Cabinet

Wipe the front panel and cabinet case clean from time to
time with a silicon cloth or a soft, dry cleaning cloth.

For heavier dirt and smudges, dip a soft cleaning cloth in a
weak solution of neutral cleanser, wring out firmly, and wipe
clean. Then wipe dry with a soft, dry cleaning cloth.

Do not use rangher cleaning materials, or volatile agents
such as thinner or alcohol, since these may well result in
scratches and erasure of lettering.

WARNING

TO PREVENT FIRE OR SHOCK HAZARD DO
NOT EXPOSE THIS APPLIANCE T0 RAIN OR
MOISTURE.

Onkyo A 7040 Owners Manual

Extracted text from Onkyo A 7040 Owners Manual (Ocr-read)

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