# Trouble getting 4 channel amp to fade/ balance channels when bridged



## IrishChamp (Oct 9, 2008)

I wired up my new systems front stage with a bridged 4 channel amp and I had to run the amp in 4 channel output mode (with only 2 channel inputs) and plug the rca's into the two left or right channels on the amp to get it to respond to balancing on the HU. I have a alpine 9887 and imprint so I wanted to make sure that the front stage made sense to the imprint processor, I was not sure if it would do it's job properly if the front left and right showed up as one or both or what ever the he'll it was doing, I could not make sense of anything before I did it this way. I'd fade or balance and it would do nothing or kill the sound all together rather than just fade to the other speakers.


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## IrishChamp (Oct 9, 2008)

crap, this is probablly the wrong forum, I just posted a more relevant topic and then remembered I had something else to post and just hit new thread again. If this is inappropriate could a mod pleAse move it. Thanks


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## bikerider (Dec 28, 2008)

Just split the RCA's from the head unit with y-adapters at the amp input, channel 1/2 will bridge to one side and channel 3/4 to the other.

I've never lost balance or fade control doing it this way.


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## rc10mike (Mar 27, 2008)

bikerider said:


> Just split the RCA's from the head unit with y-adapters at the amp input, channel 1/2 will bridge to one side and channel 3/4 to the other.
> 
> I've never lost balance or fade control doing it this way.


x2..


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## IrishChamp (Oct 9, 2008)

Hanks, I'll pick up some y's.


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## Alrojoca (Oct 5, 2012)

I tried to search about this issue and this was the thread that came up. 


Is this always the problem bridging a 4 ch amp for a 2 ch stereo output?


The balance does not work, it only goes to one side, and the other ch can still be heard at a much lower level. if going to the opposite side both channels sound very similar.

one set of RCA's were connected to the front channels, the amp's 2-4 ch mode switch was set to 2 ch. I also tried the 4 ch mode it only sounded weaker. The manual was not clear about where to connect the right or left speaker. One thing is clear the gains for front and rear channels do work independent for each speaker, other than that, the balance is useless.


Any other suggestions other than was already posted here?

Thanks 
Al


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## Jepalan (Jun 27, 2013)

Alrojoca said:


> Is this always the problem bridging a 4 ch amp for a 2 ch stereo output?
> one set of RCA's were connected to the front channels, the amp's 2-4 ch mode switch was set to 2 ch. I also tried the 4 ch mode it only sounded weaker. The manual was not clear about where to connect the right or left speaker. One thing is clear the gains for front and rear channels do work independent for each speaker, other than that, the balance is useless.
> Al


If using 4-channel mode, do this...

HU front-left preout should be connected to RCA Y-splitter into amp ch 1 & ch 2
HU front-right preout to another RCA Y-splitter then into amp ch 3 & 4

Bridge output of channels 1 & 2 to the front-left speaker
Bridge the output of channels 3 & 4 to the front-right speaker

Balance should work perfectly.

Or - tell us the exact amp model/make and I can tell you proper way to connect it setting the mode switch to "2-ch" mode.


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## Alrojoca (Oct 5, 2012)

Thanks for clearing that up in detail :rockon:

Any issues I should be concerned about if no RCA splitters are used?

I assume there is nothing wrong if the balance is not needed, to simply leave it the way it is and the only issue may be not having a stereo output if no Y splitters are used? 

Or the amp will play in stereo even without the splitters and I should have nothing to be concerned about other than the balance will not work?

thanks


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## Alrojoca (Oct 5, 2012)

I figured if the amp has a 2-4 ch mode switch, when bridged, the balance should work without any Y RCA's but I may be wrong

Here are the amp's manual instructions 




*5 ch amp.*
• Three-channel (bridged) operation: (meaning 2 since the sub's channels will not be used) *Connect one speaker to the Front terminals marked "B. " Connect the other speaker to the Rear terminals marked "B.*


Rear Input Signal Selection Switch• If your source unit has only front RCA-type outputs and they are connected to the amplifier's Front input connectors, move this switch to the FRONT setting. *( i assume they mean 2 ch mode) If your source unit has 4 RCA-type outputs, leave it in the 4CH position.*


The only thing I have left to try is simply swapping the RCA's left for right and try if the balance works, even though they are connected in the right F L channels


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## Jepalan (Jun 27, 2013)

Alrojoca said:


> Thanks for clearing that up in detail :rockon:
> 
> Any issues I should be concerned about if no RCA splitters are used?
> 
> ...


Um. No. You should be concerned. What brand and model amp are you using?


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## Alrojoca (Oct 5, 2012)

This amp

Infinity Kappa Series KAPPA FIVE User Manual (Page 2 of 4)


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## Alrojoca (Oct 5, 2012)

Anybody?

I guess, bridging amps will always remains a mystery with manufacturers, not giving enough information about balance or telling you that the balance will be lost. Even when it is perfectly safe and tell you how to connect it.

For the ones doing this frequently, I guess it is no big deal. For the ones doing it for the first time, I guess we can only learn the hard way.

Maybe a call to the manufacturer can confirm the issue, information about this, is very limited or none.

I had the same issue bridging an alpine 2 ch amp, it said how to do it, it never said which RCA to pick for the input.


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## Alrojoca (Oct 5, 2012)

I thought I would post a good link or 2, one from this forum regarding the subject of bridging amplifiers, Y RCA splitters etc, hopping it helps others.

Thanks

http://www.diymobileaudio.com/forum...amp-bridged-run-front-stage-rca-question.html

Bridging a 4 channel amp?


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## rans0m00 (Sep 22, 2011)

A little bit of a necro thread but everything fits my situation perfectly so asking... infinity kappa five bridged 4ohm passive front and 2ohm subwoofer. I can't get the balance to work on from the head unit no matter what I have tried.... so far tried the diagram adding a y splitter... tried it on 2 Chan and 4 Chan mode on the amp.... no balance.... also tried removing the splitter and had left and right front connected to the amp... tried this in 2 and 4 Chan mode too. 

All I get is sound from both fronts full time.... the mode or adjust it left or right it just lowers the volume for both pairs.

If anyone has any more feedback I would appreciate it.


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## Jepalan (Jun 27, 2013)

One of the worst user manuals I have ever read.

Put amp in 4CH mode.
Set sub input to INT.
Connect HU FL out to amp FL & FR inputs via Y-cable.
Connect HU FR out to amp RL & RR inputs via Y-cable.
Bridge FL speaker across the front "B" terminals. 
Bridge FR speaker across the rear "B" terminals.


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## rans0m00 (Sep 22, 2011)

Well of course I post about the issue and two minutes later I get it working.... So if anyone else is having this trouble with the infinity kappa five amp like I have just do this... At the moment the setup is 4 chan mode but bridged.... y connector front left is on the front rca inputs and front right is on the rear rca inputs... I could have sworn I tried this before but I guess not and it works just fine. At some point I will try putting it back in 2 chan mode and see if it still works or if it must be in 4 chan mode... also see if I can ditch the y connectors... either way have my balance back to working so I am happy for now


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## rans0m00 (Sep 22, 2011)

Jepalan said:


> Put amp in 4CH mode.
> Set sub input to INT.
> Connect HU FL out to amp FL & FR inputs via Y-cable.
> Connect HU FR out to amp RL & RR inputs via Y-cable.
> ...


Thanks! I guess I shouldn't have spent so much time in the kitchen between figuring this out and posting my solution. Anyways glad to know you came up with the same solution as i did.

Ugh extra kick in the junk... just looked at the image again and guess I looked at it the wrong way but its correct for my setup.... think its time to just put away the everything and go to bed.


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## Alrojoca (Oct 5, 2012)

rans0m00 said:


> A little bit of a necro thread but everything fits my situation perfectly so asking... infinity kappa five bridged 4ohm passive front and 2ohm subwoofer. I can't get the balance to work on from the head unit no matter what I have tried.... so far tried the diagram adding a y splitter... tried it on 2 Chan and 4 Chan mode on the amp.... no balance.... also tried removing the splitter and had left and right front connected to the amp... tried this in 2 and 4 Chan mode too.
> 
> All I get is sound from both fronts full time.... the mode or adjust it left or right it just lowers the volume for both pairs.
> 
> If anyone has any more feedback I would appreciate it.



The way I got mine to work was with Y splitters, set SW to 4 ch, and make sure you use the speaker terminals marked B on the amp with the correct polarity, the first set of terminals next to the fuses will be for the L ch. R ch split to Rear L and Rear R, Left ch Y split to Front Left and front Right and I got perfect bridged balance and stereo sound.


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