Consumer electronics equipment, such as amplifiers and radios, use mainly two types of audio connectors: RCA and 3.5mm mini phone plug. Amplifiers have a set of RCA connectors on the back; a typical radio has a mini plug output. They are distinctly different and mutually incompatible, so you cannot insert a mini plug into an RCA jack or vice versa. You can, however, obtain an adapter cable from nearly any consumer electronics outlet. Using such a cable, hooking an amp to a radio is a cinch.
RCA and mini-plug connectors come in two genders, male and female. The male RCA, also called a phono plug, is about 1/4 inch in diameter with a central pin and an outer metal flange that fits snugly over the female connector. The male mini plug has a shaft 3.5 mm in diameter protruding from a cylindrical metal or plastic body whose diameter is about 9 mm. The shaft may have one, two or three insulators along the length, separating each conductor for mono, stereo and cell phone plug types.
A standard RCA audio cable has two male connectors, one at each end. The wire itself has a central conductor and braided shield to reduce electrical interference from radio sources and fluorescent lights. The mini-plug cable has two male plugs; the cable may have one central conductor for simple connections or two for stereo. Electronics stores offer ready-made standard cables in a variety of lengths.
An adapter cable is very similar to a standard one, except it has an RCA male at one end and a mini plug at the other. The adapter cable uses the same type of flexible, shielded wire found in the standard type. Because RCA plugs carry only one audio channel, a stereo adapter cable will have a stereo mini plug on one end and a pair of RCAs on the other -- one white and one red.
Before hooking them up, turn the power to your amp and radio off. Plugging an audio source into a live amp produces loud popping and buzzing noises that can damage your speakers. Connect the stereo mini plug to corresponding audio output jack on the radio, then plug each of the two RCA plugs into the female connectors on the amp's "auxiliary" or "line level input" section, making sure you match the red and white colors to those of the female sockets. If the sockets are uncolored, plug the red male into the female marked "right channel" and the white into the jack marked "left channel." Set the output level on the radio to about three-quarters of full volume, and then turn the amp's volume level all the way down. Turn the radio and amp on and slowly adjust the amp's volume to a comfortable listening level.
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