Margules ACRH-4 Manual Del Usuario página 21

5. The sound is distorted, or a humming sound is
heard:
Check that both the source cables and the
•
speakers' cables are properly connected to the
terminals on the amplifier.
Make sure the signal source is operating correctly
•
and that the line level sources are not connected to the
phono stage input.
Verify the preamp tubes are properly installed on
•
their sockets.
One of the tubes may be damaged.
•
In order to identify a defective tube, check that the LED
indicator are lit.
If the LED indicator is not lit, the tubes must be replaced.
6. A humming sound is heard in both channels
regardless of the position of the volume control:
• The noise could be caused by a ground loop.
Unplug all the components from the amplifier except for
the speakers. If the hum disappears you have confirmed
there is a ground loop. We suggest you to connect the
sources one by one to identify the one causing the
ground loop.
If you hear the humming sound while listening to your
turntable through the Phono Input check that the
turntable's ground wire is properly connected to the
ACRH-4 ground screw.
ENGLISH - 21