Bridging an amplifier is the process of combining a set of channels into one with half the ohms.

The technique has become popular among many car owners because it allows amplifiers to send out a more powerful mono signal to the speakers or subwoofer.

For example, you have a 2-channel amplifier installed in your vehicle with a rating of 75 watts (RMS) for each channel. At 4 ohms, it may be able to push out as much as about 200 watts into a single channel when bridged.

Tips to Consider Before Bridging Your Amplifier

Since not all amplifiers can be bridged, the first and most important thing you need to consider is what category yours falls into.

Secondly, it is worth noting that bridging cuts the resistance load or ohms in half; this can quickly cause your amplifier to overheat and potentially shutdown. Consult your manual (located in the product information page) to if your unit can function at half the ohms it was originally intended to. Other amplifiers are also internally bridged and do not require any further bridging.

How to Bridge your Amplifier

If you have a two-channel amplifier in your car’s system, you should be able to see 4 terminals; two positives and two negatives. Channel 1 will be labeled A for positive and B for negative while channel 2 will be labeled C for positive and D for negative. To bridge, begin by connecting the amplifier to the speaker.

From the speaker wires, connect the positive lead to terminal A and the negative speaker lead to terminal D. You can achieve this by using a Phillips screwdriver to unscrew the terminal screws. Next, place the wire between the bottom and top portions of the terminal and put the screws in place. This connection combines all the power from the two separate channels and doubles your power output.

If you have a four-channel amplifier and want to bridge it with two subwoofers, the procedure is pretty much the same as the previous amp with a few minor differences. First take the necessary precautions to ensure that your amp can be bridged.

On a typical 4 channel amplifier, you should see a total of 8 terminals; channels 1 through 4 are labeled as follows. The first channel is marked A for positive and B for negative. Channel two reads C for positive and D for negative. Channel 3 has an E for positive and an F for negative terminals while channel 4 indicates G as the positive terminal and H as the negative terminal.

Connect sub 1 to the first two channels just as you would normally do for a two channel amplifier. This means you will connect the positive wire to terminal A while the negative wire is connected to terminal D. For sub 2, connect the positive lead wire to terminal E while the negative lead should go to terminal H. Now your amp is bridged!