Tips; Search For Errors - VINCENT SP-995 Manuel D'utilisation

Burn in/ Warm up
Your audio components need a certain time
period until they reach maximum performance.
The duration of this "warm up" time is very diffe-
rent for the various elements of your audio system.
Higher and homogeneous sound quality is achie-
ved while keeping the device switched on.
Your audio specialist dealer has enough experi-
ence to give you more information.
Net frequency noise
Some audio source devices may in combination
with the amplifier cause a humming noise at power
line frequency audible from your speakers. Usually,
its volume varies with the volume setting of the
amplifier. This is no sign of a defect or fault of your
audio products but has to be eliminated.
Generally, every wall-powered device connected
to the ground wire of the power plug can cause this
problem when connected to the amplifier.
Experience shows that this problem is mainly cau-
sed by antenna-connected components (as TV-sets
or Tuners), personal computers, electrostatic loud-
speakers, subwoofers, record players or headpho-
32 Vincent

TIPS

ne amplifiers that are connected to the audio
inputs of the amplifier. Another possible reason for
humming noise is electromagnetic interference of
other components' power supplies with pick-up-
systems of record players (change the place of the
record player for a test).
In most electric devices the ground potentials of all
signals are connected to each other at one central
point, where they have one common connection.
If the device uses the protective conductor of the
wall outlet, the corresponding wire of the line cord
is connected intractably to the metal housing of
the device. This is the mostly the point where the
central grounding point is attached to. By doing
this the housing is able to shield all signals from
external radiated noise. Some main amplifiers are
equipped with a "Ground Lift"-switch. If it is acti-
vated, ground potential of the chassis and the pro-
tective ground wire are being separated from the
central signal ground point. The protective ground
wire keeps its function. Sometimes this helps pre-
vent noise caused by errors in grounding.
If the problem occurs and cannot be solved by
yourself your audio specialist dealer will help you.

SEARCH FOR ERRORS

Symptom
Possible Cause
Unit does not work Mains cable is not connected to a suitable
mains wall outlet.
after pressing the
power button
Mains cable has not been firmly inserted into
wall power socket and the device's socket
(8). Otherwise it may be defective.
A cable is connected to "POWER CON-
TROL" at the rear of the unit. In this case the
"POWER" (2) button is inoperable.
Unit fuse or unit is defective.
The audio source currently selected at the
No sound, appliance
preamplifier is giving no signal.
is switched on (the
LED (3) on the front
The output of the source device is not connec-
of the device is lit)
ted or is wrongly connected e.g. not connec-
ted to the selected input channel terminal of
the preamplifier.
Wrong input channel has been selected at
the preamplifier.
Volume setting of the preamplifier is set too low.
The preamplifier has been muted (MUTE-
Function).
Output of the preamplifier not connected or
incorrectly connected to the input connector
of the SP-995.
The setting of the toggle switch "XLR IN" (4)
on the front panel is not correct.
The speaker cable is not properly connected to
the main amplifier's terminals (5) or is defective.
The cable connections are not tight, the con-
Poor sound quality
nectors are dirty or a cable is defective.
A record player has been connected to a line
level input of the preamplifier without using a
phono preamplifier.
An audio source with standard line level out-
put (example: CD player) is connected to the
power amplifier direct input "LINE IN" (6).
Humming low frequen- See section "Net frequency noise" in the
chapter "Tips".
cy noise is audible,
even as no audio sour-
ce is playing back
Countermeasure
Connect to a functioning socket using a suit-
able mains voltage.
Check the power cable. If necessary,
exchange it with a suitable mains cable and
push its plug firmly into wall socket and the
device's power connector.
Disconnect the "POWER CONTROL" cable
or turn on the unit outputting the signal.
Contact your dealer.
Switch on the source unit and begin play-
back.
Correct the connection.
Set the preamplifier to the input that your
desired source is connected to.
Carefully increase the volume of the preamplifier.
Deactivate the MUTE function at the preampli-
fier after, as a precaution, reducing the volu-
me level.
Correct the connection to the preamplifier.
Set the selector to the correct input.
Check and tighten the speaker cables at the
main amplifier and the speakers.
Check the cables and cable connections.
Interconnect a phono preamplifier.
Do not connect line level audio sources at the
inputs "LINE IN" (6).
See section "Net frequency noise" in the
chapter "Tips".
Vincent 33