Tag: bridging an amplifier

How To Strap Two Amps Together, Double Your Power!


For this how-to, I’m going to use the DC Audio 7.5k .

For the most part, “Strapping” – aka ‘Bridging’ – TWO amps together is done to get Double the @1ohm Power Rating of One Amp. This makes the setup – AFTER “strapping” – stable ONLY to a 2-ohm final load . That, in of itself, is fairly confusing so here’s an explanation…

First, it is of the UTMOST IMPORTANCE that you ONLY ‘strap’ two IDENTICAL TWIN AMPLIFIERS! Moreover, it is also important to make sure that the amplifiers have the ability to be strapped (i.e. the features necessary to successfully perform this), and that ‘Strapping’ is a manufacture confirmed ability of the amplifiers.

DC Audio 7.5k

DC Audio 7.5k

  • 4-ohms: 2000 watts x 1 ch.
  • 2 -ohms: 4400 watts x 1 ch.
  • 1-ohm: 7500 watts x 1 ch.

From the above specs, we establish that ONE DC Audio 7.5k is able to put out 7,500w RMS @1-ohms. Therefore, in theory, If we strap TWO DC Audio 7.5k together we can achieve 15,000w RMS @2ohms!!

The most crucial part of successfully Strapping two amps together is the Wiring! Starting with the Easy part, RCAs:


    • Step 1. Connect the Master amplifier to the head-unit (duh!) and set the amplifier’s output-master/input-slave switch to Output Master.
    • Step 2. Set Slave amplifier output-master/input-slave switch to Slave Input.
    • Step 3. From the ONE RCA-Connector – that has a line from said switch – Connect an RCA cable from the Master to Slave amplifier.

DO NOT USE THE PAIR OF RCAS LABELED ‘OUTPUT’!!!! This “Output” will ONLY send an AUDIO SIGNAL, and Will Not allow for the following important part to happen……

Intermission: The Output-Master/Input-Slave Switch , if you haven’t already figured it out, will turn one amp into the Masterand the other into the Slave. But what does this mean exactly? This means – The Master amp will be in absolute control of the Crossover Points, The Gain, & The Remote Level Control. Implied, the SLAVE will have absolutely NO control abilities, those settings will be turned Off . Therefore to “Tune” the amps – plural – you ONLY ‘Tune’ the Master amp!

Next part of the install is where everyone gets lost; the speaker wire connections.




  • Step 1. Connect 12-Gauge Speaker Wire from the Positive (+) Speaker Output on the Master amp to the Positive Terminal on the Subwoofer (+). Amp (+) to Sub (+)
  • Step 2. Connect 12-Gauge Speaker Wire from the Positive (+) Speaker Output on the Slave amp to the Negative Terminal on the Subwoofer (-). Amp (+) to Sub (-)
  • Step 2.5. Please Re-Read Step 2 . This is the part EVERYONE gets wrong. 
  • Step 3. Connect 12-Gauge Speaker Wire from the Negative (-) Speaker Output on the Master amp to the Negative (-) Speaker Output on the Slave Amplifier. Amp (-) to Amp (-)

These connections is what Physically ‘bridges’ the amps together!

From this point on you can go about the install as you would any other install. Make sure all your connections are made properly, tighten everything down, mount what needs to be mounted, etc… Then, start the Tuning process; tune the MASTER AMP ONLY!!!

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How to Bridge an Amplifier


Bridging refers to combining two (four) channels of an amplifier into one (two) channel(s) with twice the voltage. A two channel amp can be bridged to one channel, and a four channel amp into two channels. Bridging the channels increases the power output. An amplifier is usually bridged to combine two channels to power one subwoofer, or to combine four channels into powering two subwoofers.  To clarify, you cannot bridge a monoblock amplifier! The definition of bridging is combining two or more channels, and a monoblock amplifier has only one channel. You will need opposing channels in order to bridge the amplifier. In technical terms, you using a low source impedance to drive a large load impedance, which results in maximum voltage transfer.

Bridgeable amplifiers are designed with an inverted channel for bridging purposes. The inverted channel produces voltage that is generated at the opposite polarity of the regular, un-bridged channel. Bridging an amplifier produces almost four times the amount of power as it would in an un-bridged status.

Before you attempt to bridge an amplifier, there are certain conditions you must keep in mind. Only bridge an amplifier that can handle the increased power load. Do not bridge an amp that will be unstable at the bridged load, or if the speakers cannot handle the increased power. Always check your product’s paperwork and diagrams before you bridge your amplifier. Using your amplifier’s paperwork is the easiest way to figure out how to bridge your amplifier.

Unless otherwise stated, all multi-channel amplifiers have a minimum bridged stability that is higher than the minimum stated impedance from one of its channels. For example, a 2 channel amplifier that is 1 ohm stable per channel would have a minimum impedance of 2 ohms when bridged. In reality, most amps are only stable at a 4 ohm load in mono/bridged configuration.

Amp Bridging

To bridge your amplifier, locate the amp terminals. For a 2-channel amplifier, you will see four terminals. A positive and a negative terminal for channel one, and likewise for channel two. If you are bridging this 2-channel amp to one subwoofer, you will connect one piece of speaker wire from the positive terminal of channel 1 to the speaker’s positive terminal. Next connect a separate cut of speaker wire to the negative terminal of channel 2 to the speaker’s negative terminal.

That’s the gist of amplifier bridging. If you are totally inexperienced, ask a knowledeable friend to help guide you.

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