Instructables

how do I bridge a stereo car amplifier?

http://www.drdetailshop.com/d2150.htm this source say that my amp is bridgeable and that it can run stereo and mono simultaniously. It is a 2 channel amp, however I only have one speaker.. I need both left and right channels running into the speaker.
How can this be done?
What would be the impeadance if the amp is running at 4ohms and the bridged subwoofer speaker is 4 ohms?
what would be the overall wattage?
how do i do this without causing damage toi my sub,amp, or radio?
does this put excess strain and/or heat on the amp? if so how do I fix this?
is there any wiring gauge problems that i should be concerned about? (18 gauge for input power, 18 gauge for speaker output, plan to lower the gauge of the speaker to somewhere around 12 or 14)

Phoghat3 months ago

http://www.bcae1.com/bridging.htm

thegeeke2 years ago
Basically to bridge the amp you just use a piece of wire and chain the positive leads together and the negative leads together, then connect your positive lead to the positive chain and your negative to the negative chain.

By doing this you are going to double the power on the one channel. Your speaker could easily blow if you turn the volume up all the way, but as long as you are responsible with your volume, then you shouldn't have any problems. Normally, I would use two speakers in a mono bridge, so if you want to play it safe, put some resistors in the chain line. It will not put any more strain than having two speakers... one on each channel. Even then, your speaker will blow before your amp in this situation. Your radio will have nothing to do with this, since the radio is an input device. Amp and speakers are output devices.

12 or 14 gauge shouldn't be a problem as far as I know.

I have never seen stereo and mono bridge running from the same channels before... by pure definition I don't think that it is possible. You are mixing the signals from both channels together... by doing that, you loose individuality. I think that all they mean by mono bridgeable is that you can bridge the channels without the amp thinking that it is a short and shutting off. Many amps with short sensing circuitry will think mono bridging is a short.

I'm not really an expert on car audio, but I do professional audio. What I explained is what we use in pro audio, but I just want the disclaimer in here that it could be different in car audio.

Good luck! :)
fastcar123 (author)  thegeeke2 years ago
That could work. But wouldn't combining the 2 channels in that way feedback amplified electricity back into the the MOSFETs, eventually destroying them?

Honestly the speaker will be replaced anyway. It is a pyramid speaker and therefore having horrid quality. It is going to be installed so it can last until I can afford a new speaker and to test to see if the wiring arrangement will work.

Unfortunately the amp does have a short circuit protection sensor built in so I'm not sure if this will work the way I intend for it to.

I've connected the system as a trial before using an ATX power supply and an mp3 player but even then I couldn't figure out how to connect left and right channels into one speaker
If the amp claims to be mono bridgeable, then A. it shouldn't feedback into the MOSFETs, and B. the short sensing circuitry should recognize it as a bridge and not a short. (Again, that's how it works in pro-audio... not sure about automotive.)
fastcar123 (author)  thegeeke2 years ago
So just connect the left output positive to the right output positive then to the speaker and do the same thing for negative?
Correct.
fastcar123 (author)  thegeeke2 years ago
And that shouldn't damage the amplifier in any way shape or form?
I've done it many times, the only thing that I have run into is occasionally short sensing circuits will shut off the amp because it thinks it's a short. But I've never run into permanent damage. (Again, not sure about car amps... just what I've used in pro-audio.)
fastcar123 (author)  thegeeke2 years ago
What could possibly be different from pro audio and car audio?
I don't think that there is any difference, maybe just in the quality and durability of the equipment. I'm just putting the warning out that I have really not worked with car audio, so I don't know.

There will defiantly be a difference in the quality between pro and car. Reason being: As a pro-audio specialist, I require my equipment to do more than most consumers do, therefore it must have much more quality and durability than consumer products. The connections are generally different, and although some really high end consumer products can match the quality of pro, generally they aren't as durable, and it would have more automatic processing than pro would. (Consumers wouldn't know how to do the signal processing themselves, but pros don't trust automatic to be accurate enough for their purposes.)

Sorry if I rambled on about the differences between Pro and Consumer products, but I would put automotive audio in the consumer category, so I'm just putting the differences that I know out there.

Good luck with your project. :)