Classe Audio CP-500 - Manual (Page 40)

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• If you have the optional phono module in your preamplifi er,
make sure that the ground wire of the tonearm is secured
properly to the ground lug on the back of your preamp.
• If the hum exists only on the phono input, make sure
the turntable/tonearm assembly is not too close to other
components. Th
ere should be at least 12 inches (30cm) clearance
from the other components. Th e more clearance you provide, the
better (as long as the tonearm cable is not stretching).
• Make sure the tonearm cable is not touching or running
alongside an AC cable.
• Make sure you have the proper loading for your phono cartridge.
If you are in doubt, consult your authorized Classé dealer.
6. There is a mechanical hum coming from the unit.
• Th is symptom suggests you have a lot of electrical noise on your
AC mains line. Try connecting to another AC circuit (not merely
a diff erent plug, but a diff erent circuit).
• Check to see if you have any halogen lighting or dimmers on the
same circuit as the preamplifi er, as they can be the cause of hum
in power supply transformers.
7. There is a noticeable change in volume between one input
and another, even though the volume was not adjusted.
• You may need to adjust the input off set setting to compensate
for diff erences in output level between source components.
Conversely, the input off set setting may have been adjusted
inappropriately. Either way, you can correct the problem by
going to the following location in the menu system:
Menu • system setup • input • input name • off set
where input name is the input which needs to be adjusted.
• If the input that seems incorrect is the phono input, make sure
you are using the proper gain setting for the type of cartridge you
are using. If in doubt, consult with your authorized Classé dealer.