Guitar amplifiers are normally connected to speaker cabinets to create sound. However, there may be times when a speaker cabinet is unavailable, or the amount of volume created by a speaker cabinet would be too high. In these circumstances, it may be possible to connect an amplifier to a TV, provided both have the necessary inputs and outputs.
Amplifier Line Out
Most guitar amplifiers made since the 1980s -- especially solid state models -- include a line out connection. This allows the player to send an unamplified signal from the amplifier to another device such as a recording console or other guitar amplifier. The line out can also be used to connect the amplifier to a TV. The line out is usually a quarter-inch phono jack found on the back panel near the speaker outputs, and may be labeled line out, preamp out or slave out. In amplifiers with effects loops, the effects send may also be used as a line out.
TV Audio Connections
Most TVs allow the user to connect more than one signal source, and with the exception of HDMI connections, stereo RCA connections are used to supply TVs with audio signals. If you want to connect an amplifier to a TV, you will need to find an available audio input or temporarily disconnect another device. Some TVs include auxiliary connections on the front or side panels for temporary connections. Check for these first before going behind the TV.
To connect a guitar amplifier to a TV, you will need a cable with a quarter-inch phono plug on one end and RCA connectors on the other. When you are ready, insert the phono plug into the amplifier's line out jack, then connect the RCA connectors to an available input on the TV. Once you have made the connection, turn on the amplifier and TV, set the TV to the corresponding input and use the controls on the TV to set the volume level.
It may be difficult to find the cable described in general merchandise or electronics retailers. If you cannot find a cable with these exact specifications, look for one with an eighth-inch phono plug instead of a quarter-inch plug. These are commonly sold for use with MP3 players. You can then use a separate quarter-inch to eighth-inch adapter -- commonly included with stereo headphones -- to connect the cable to the amplifier. Because most guitar amplifiers are monaural devices, you may only hear a signal from one TV speaker after connecting the two devices. If possible, use the TV's menu options to set the audio output to mono to restore sound to the missing channel.