The phono inputs on receivers that have them boost a turntable's signal, which is too weak to drive an amplifier's line-level input on its own. In this case, the receiver has a built-in preamplifier that increases the turntable's signal to useful levels. You can, however, use a receiver without phono inputs by connecting an external phono preamplifier between the turntable and the receiver.
Things You'll Need
Shielded audio cables, RCA connectors on each end
Step 1: Turn Power Off
Turn power off to your receiver, turntable and preamp.
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If you connect the phono inputs while the receiver is on, the receiver may produce a loud hum, possibly damaging your speakers.
Step 2: Connect Turntable to Preamp
Connect the two output audio cables coming from the turntable to the preamp's inputs.
Note that audio cable connectors are marked with a colored band; a red band signifies the right stereo channel, and a white or other colored band signifies the left. Match the connector colors with the inputs, which may themselves have a color mark or a label such as “left” or “right.”
Keep the cable length between the turntable and preamp as short as is practical — 3 to 6 feet is a reasonable distance. Even with shielded cables, radio and electrical interference can add excessive noise to the turntable’s weak signal. In addition, electrical capacitance, which increases with longer cables, can compromise the turntable’s sound quality.
Step 3: Connect Preamp to Receiver
Connect two cables to the preamp's outputs, one cable to each output. Connect the other end of these cables to the receiver's line-level inputs. The receiver inputs may be marked "Line," "Aux" or "Tape." Switch the receiver's input-select knob to this setting when you use the turntable.
Step 4: Ground Turntable to Preamp
Connect the turntable's ground wire to the grounding post on the preamplifier.
The grounding wire is typically a thin green wire with a C-shaped metal spade lug connector. The ground wire is connected to the metal turntable chassis and may be on the underside of the chassis.
Step 5: Turn Power On
Turn power on to your receiver, turntable and preamp.