If you’re planning on connecting a car radio to an existing house outlet for your home audio system, there are a few things you need to know. These tips will help you avoid headaches, protect your investment and get a better quality audio system.

Connecting a Power Wire for Your Stereo

The first thing you need to do is make sure your new radio comes with the correct power wires for your car. If not, it will be very hard to install your new head unit.

This is a good time to find out how much current (amps) the old wiring will draw so you can plan accordingly and choose an appropriate adapter that will give your new radio enough power.

It’s also a good idea to check the voltage of the existing wires before soldering them. If they’re too low, it could affect your radio’s performance and even short circuit it.

To connect the power wire, use a pair of soldering irons to solder the new wiring in place. Then, secure it to the back of the radio with electrical tape. This will prevent the wires from rubbing against each other or touching when you slide your radio into the dashboard frame.

The next step is to solder the speaker wires to the new wiring as well. It’s very important to do this properly because a loose connection between the wires can result in static noise or a blown speaker. It takes about 30 minutes to solder a full set of wires and a bit less time if you’re only connecting the power side.

You’ll want to ensure that you’re connecting the +12V constant power wire (usually red) from your supply directly to the radio as well as the accessory/on wire (usually red). Using an on/off switch in between is a good idea. This will allow you to turn the radio on and off without losing any of its memory settings or presets.

Remember that if you disconnect the power from your +12V supply, the radio will lose all its memory settings & presets. This is a big “gotcha” and it can be very annoying. It’s especially true if you’ve made many adjustments to your radio and are happy with the way it works.

It’s a good idea to hook up the radio memory wire to one or more low-ampere power sources, such as a small 12V AC-DC adapter or a miniature 12V battery pack. This is to ensure that your new head unit will retain its settings and presets even if the main power supply is turned off.

Another option is to connect the radio memory wire to a 5V to 12V step-up supply, such as a USB external battery pack. You can also use a USB extension cable to connect the wire. This is a convenient option but I wouldn’t recommend it if you want to be able to play your music at high volumes without damaging your speakers.