Harman Kardon Harman/kardon HK3490 Owner's Manual page 11

REAR-PANEL CONNECTIONS
CD and Tape Inputs:
These jacks may be used to connect your
audio-only source components (e.g., CD player, tape deck). Do not
connect a turntable to these jacks unless you are using the turntable
with a phono preamp. When your recorder features three-head or
off-head playback, you may monitor a recording as it is being made.
Phono Inputs and Ground:
Connect the outputs of your turntable
or tonearm to these jacks, and connect the ground wire from the
turntable to this Ground Connector to reduce system hum. Only moving-
magnet (MM-type) cartridges are compatible with the Phono Inputs. If
your turntable is equipped with its own onboard phono preamp, you
may connect it to any of the HK 3490's other audio inputs.
Main Power Switch:
This mechanical switch turns the power supply
on or off. It is usually left turned on (push the rocker in at the top), and
cannot be turned on using the remote control. Turn this switch off when
connecting or disconnecting source devices or loudspeakers to prevent
any possibility of damage to components resulting from an unexpected
power surge.
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