how to bridge an amp

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skitz
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how to bridge an amp

Post by skitz »

well i guss the topic covers it, i want to make my 4ch a two ch to use the 150wrms X2 at 2ohm...

cheers
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AVICJR
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Post by AVICJR »

Take the + of the right channel and the negative from the left channel. Do this for the front , then repeat the process for the rear and you've made your 4 channel amp a 2 channel amp. Sometimes the amps will label which outputs to use to bridge them.
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Bfowler
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Post by Bfowler »

are you sure 2ohms bridged is recommeded for that amp? most 4 channels arent.
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1moreamp
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Re: how to bridge an amp

Post by 1moreamp »

skitz wrote:well i guss the topic covers it, i want to make my 4ch a two ch to use the 150wrms X2 at 2ohm...

cheers
Give me a PM if it goes south on you. 4 channel amps are best left running corners not subs IMHO. something to do with too much power unequally distributed into ONE channel causing them to fail.
Next to sub amps my main repair business is 4 channel amps running subs. But if you operate it sanely it should give reasonable service.

Why not buy a sub amp, they are cheap now-a-days ? I just cleaned up one of this forum members amp after running subs on two of the four channels, Caught it before it failed outright from excessive bias , and way huge DC offset from being driven into clipping running bassline < people have a hard time hearing clipped bass for some reason>.

It happens to most everybody, so if this happens to you don't feel too bad . I see it all the time especially from folks trying to save money by using what they have and not buying what they need. Happens a lot :wink: Just a FYI from the repair guy. 4 Channel amps cannot control how much power that goes thru each channel separately so at any given moment the entire 4 channel power can pass thru a single channel, thus reducing it to a smoldering mass of fused and molten metal after letting all of its smoke out into the car :( It happens, best of luck watch your gains and drive levels and you should be ok...C
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stipud
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Post by stipud »

Actually I think he has an Octane-R 15.0:1 for his subs. I believe the 5.0:4 is only being bridged down to 4 ohms in order to run his front components, so this should work out fine.
tsonka
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Post by tsonka »

C are you suggesting that bridging my 200.4 to my 2 new dual voice coil subs isnt the brightest idea?

Planning on running them 8ohm if that makes any difference. Figured that would make the amp smile
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1moreamp
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Post by 1moreamp »

tsonka wrote:C are you suggesting that bridging my 200.4 to my 2 new dual voice coil subs isnt the brightest idea?

Planning on running them 8ohm if that makes any difference. Figured that would make the amp smile

Morning all,
Well Yes to be exact. You see the 4 channel 200 watt per channel amp has a single power supply that in the real world should be capable of running all 4 channels to full power, 4 times 200 or 800 watts total output, BUT there is no control method inside any of these 4 channel amps to to steer and or control the amp so 800 watts does not try to play thru just one channel.
Nothing but ohm's law at the load, but thats not gonna do much control when a single channel is over driven way past its Safe Operating Area by bass, or low ohm loads.

This is something to think about as its absolutely true about 4 channel amps, that have a single power supply inside them < like all of them I know about except the MS-1000>. There are a lot of reasons for mono designed amps but power supply control is one of the main reasons.

Now in a two channel amp designers have over-built the channel to handle a factor of two output just to be safe in design, BUT in a 4 channel amp that channel might just see a Factor or 4 times its output at any given moment and it will be un-controlled and at 4 times the output power the single channel was rated at, well you can figure that out i am sure.

Even Pg with its over-built design might have a tough time handling that sort of trouble.

I don't mean to scare you guys off, but I am sharing the real world of what I have seen over a long period of repairing amps <like 20 + years>.
So this is nothing new, its been around a long time. I just feel that a 4 channel amp was meant to run 4 independent channels and they do that job very well.

Just because something is bridgeable does not mean it should be bridged. Bridging is sort of a after thought with most amps these days, but I remember when you had to buy a separate bridging adapter to bridge a amp back in the very beginning of this industry, and even them some amps were not bridgeable by there very internal design < they were already bridged inside>

Anyway, just my techy 2 cents worth. If you operate your bass amps responsibly you can get by with a bridge setup. But I would not try to run SPL with that setup as its sure disaster just waiting to happen.

Oh if the amp is capable of delivering say rated power + dynamic headroom of say 3 DB's then a single channel might see 8 times its rated output at any given moment, just something to think about as I don't believe any amp maker builds them that tough as it would cost way too much money to build.

On the Xenon 8 ohms mono is the same as 4 ohms stereo, your just adding the ohms here, so your running the amp technically at 4 ohms per channel, which is cool to my understanding. thats the way I run mine. Bass like the way we like to hear it now-a-days has to be driven at levels up to 10 times the matching level for mids and tweets. this is what over drives 4 channel bridged amps into failure.

After all these years of doing amps I came to the conclusion if you want a 1000 watts, buy a 1000 watts at 4 ohms don't try to load a amp to get your desired power level. thats sort of like driving your car everywhere at 200 miles per hour all the time, somethings gonna give, and the harder you push the quicker it will give. :wink: especially on lower quality amps.

I hope some of this had made sense to you folks. Just trying to share a touch of reality with all of you. If your a safe and sane person, you should be able to bridge 4 to 2 and live happily. its just that other fringe group that have issues with this sort of setup. Maybe none of this applies to you. then again maybe it does apply to some of you. :)
skitz
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Post by skitz »

stipud wrote:Actually I think he has an Octane-R 15.0:1 for his subs. I believe the 5.0:4 is only being bridged down to 4 ohms in order to run his front components, so this should work out fine.
ur spot on the money there man
AVICJR wrote:Take the + of the right channel and the negative from the left channel. Do this for the front , then repeat the process for the rear and you've made your 4 channel amp a 2 channel amp. Sometimes the amps will label which outputs to use to bridge them.
cheers for that man...
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