# how to bridge a non-bridgeable amplifier?



## draft6969 (Aug 4, 2009)

More specifically I have my linear power 2002 which is non bridgeable. I know i can use the XO2, but i was seeing if there were any other crossovers that do the same thing or a simple way to do it without anything else?


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## sqshoestring (Jun 19, 2007)

Bridging is done in the op-amps I believe, where one channel is reversed in polarity. There have been devices that let you do it on the input for subs, but they are not precise enough to run higher frequencies that way. I don't recall the X02 bridging when I used them, but they were a nice xover. 

I wanted to change an old amp to bridged too and talked to a guru, he said it just is not worth trying to do.

Unless you mean making it mono? Many xovers/HUs can do that, I used to tie the rca together but that is not the correct way to do it. In reality you can usually just not worry about it. A DVC sub will mono it and most music content in sub ranges has been mono'd when it was produced/mixed for better bass sound.


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## miniSQ (Aug 4, 2009)

sqshoestring said:


> Bridging is done in the op-amps I believe, where one channel is reversed in polarity. There have been devices that let you do it on the input for subs, but they are not precise enough to run higher frequencies that way. I don't recall the X02 bridging when I used them, but they were a nice xover.
> 
> I wanted to change an old amp to bridged too and talked to a guru, he said it just is not worth trying to do.
> 
> Unless you mean making it mono? Many xovers/HUs can do that, I used to tie the rca together but that is not the correct way to do it. In reality you can usually just not worry about it. A DVC sub will mono it and most music content in sub ranges has been mono'd when it was produced/mixed for better bass sound.


how will a DVC sub "mono it"?


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## draft6969 (Aug 4, 2009)

Not talking about mono. I would like to bridge it on a SCV punch sub. so i would either just use one channel or find a way to bridge it. i know you need to invert one of the channels which i believe the XO2 does. also just like the old orion's that needed the BDG400 to bridge them.


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## minbari (Mar 3, 2011)

Its not hard. Invert one channel and drive a single speaker with both positives. This is how all bridgable amplifiers do it

Btw, reversing polarity on the RCA and inverting the signal are two different things

Sent from my motorola electrify using digital farts


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## sqshoestring (Jun 19, 2007)

miniSQ said:


> how will a DVC sub "mono it"?


Run a channel into each VC and it will play mono.


minbari said:


> Its not hard. Invert one channel and drive a single speaker with both positives. This is how all bridgable amplifiers do it
> 
> Btw, reversing polarity on the RCA and inverting the signal are two different things
> 
> Sent from my motorola electrify using digital farts


Exactly, you have to redesign the preamp section to do this and I forget what else if anything has to be changed. I even got the schematic for the amp I wanted to do it with. It would be a project. Each amp does the preamp their own way, so hard to say how many things would need changing. The amp I wanted to do used ICs in there making it even harder to deal with.


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## minbari (Mar 3, 2011)

As long as the negatives are common, all you need to do put an inverting op amp on one channel. This can be done externally.

That is all the Orion "bridging module" was.

Todays bridgable amplifiers actually have one channel inverted. At the output the neg and pos are actually backwards  that is how it stays in phase in stereo, but allows bridging by just wiring

Sent from my motorola electrify using digital farts


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## miniSQ (Aug 4, 2009)

sqshoestring said:


> Run a channel into each VC and it will play mono.
> .


no it won't.


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## Oliver (Jun 25, 2007)

miniSQ said:


> *no it won't.*


*Tru dat !*

Buy a bigger amp and sell this one 

... or better yet just throw it in your next bon fire


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## Angrywhopper (Jan 20, 2010)

I agree with the bonfire suggestion


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## sqshoestring (Jun 19, 2007)

miniSQ said:


> no it won't.


Oh, summed? I doubt most people could tell with sub bass frequencies even if you did find some music not mixed mono in the bass.

2002 was a nice amp, I'd still run one in certain installs. But got rid if LP amps long ago and used the cash elsewhere.

I was told the bridging modules were only for bass and even then you may not want to use one for SQ things. I was going to make one to bridge the amps I have.


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## Oliver (Jun 25, 2007)

sqshoestring said:


> Oh, summed?* I doubt most people could tell* with sub bass frequencies even if you did find some music not mixed mono in the bass.





> So if you collapse that mix to mono you will hear a difference because they're out of phase.


Most people can't hear phase differences 

Damn, that's got to suck


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## minbari (Mar 3, 2011)

Oliver said:


> Most people can't hear phase differences
> 
> Damn, that's got to suck


at sub frequencies? when they are only a few degree off? I bet you cant either


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## ATOMICTECH62 (Jan 24, 2009)

Some crossovers have a normal and inverted out on the sub channel.Run the normal to left input and the inverted to the right input on the amp and it can now be bridged.
Most of the old school Hifonics crossovers have these outputs.


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## Oliver (Jun 25, 2007)

draft6969 said:


> More specifically I have my linear power 2002 which is non bridgeable. I know i can use the XO2, but i was seeing if there were any other crossovers that do the same thing or a simple way to do it without anything else?


Power is cheap 

You can do better than 2 x 100 watts, for your subwoofer


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## draft6969 (Aug 4, 2009)

ATOMICTECH62 said:


> Some crossovers have a normal and inverted out on the sub channel.Run the normal to left input and the inverted to the right input on the amp and it can now be bridged.
> Most of the old school Hifonics crossovers have these outputs.


Thanks, That is what i figured. I found that the linear power x02 does it and the old audiocontrol 2xs does it. I will look into some old hifonics and see which ones do it.



Oliver said:


> Power is cheap
> 
> You can do better than 2 x 100 watts, for your subwoofer


i have a sub that is 150 watts rms so why would i want more? this is a old school install with old school components.


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