Confused on bridging 4 channel amp to 3 channels

[Bubblebass 10+ year member]

The MB Quart 4125 says to bridge channels 3 and 4:

"Connect mono line input via Y adapter from mono source or single L or R RCA from stereo source. **Note** do not connect left and right stereo signals together to achieve a mono signal as this will damage the output stage of the source and possibly the input stage of the amp."

OK....uh....how do I bridge the 2 rear channels for a sub?

Am I right in thinking use only 1 of the 2 RCA cables from the back of the HU, then use a Y at the amp?

If so, what do I do with the other RCA that is hanging out not plugged into anything? It seems like it would be susceptible to interference.

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[okiedokie 10+ year member]

What head unit do you have?

If you have sub out then use that.

I've been playing the dsc 480 which only 45watts less channel,

what I've tried are for a three way

1) take the front RCA' s to channels 1&2 for stereo.

2) take channels 3 & 4 ( sub output or rear channel) add a

y-adapter, take channel 3 & divide the channel with the adapter ,

so now you have two out puts on one channel which will plug into now.

Do the same with channel 4 now- remember to have the setting into 4channel mode.

Channels 1&2 can be set on high pass filter or full.

Take channels 3&4 set the low pass xover, now you can set you gains, xover,

to your liking.

 

[okiedokie 10+ year member]

Remember when you bridge over that amp you can't go

below 4ohms

so make sure your subs or sub 4ohms

 

[Bubblebass 10+ year member]

I only have 2 RCA outputs to work with from my head unit.

I think I am only supposed to use one of the RCA's and split it into two to get a mono signal.

Yes, I am getting a 2 ohm DVC sub for a 4 ohm total to the rear channel bridged.

 

[okiedokie 10+ year member]

Yes your right split the RCAs into four.

Are you getting 1sub or 2 subs?

Wish subs or sub are you planning on buying?

 

[Bubblebass 10+ year member]

Uhhhh...huh? Split them into 4? U mean use 3 and then split the rear into 2 like I was originally thinking?

Not positive on the sub yet but I think I am going to get one idqv2 12" with 2 2ohm coils

 

[Bubblebass 10+ year member]

Double post

 

[Bubblebass 10+ year member]

Bump.......

 

[dweLz 10+ year member]

Bump.

I need a lil help also.Im hooking up an mbquart rwe-302 and a set of components to one of these amps and im confused as all hell how to connect the rca`s.

 

[RAM_Designs 5,000+ posts]

High RCA from radio to channels 1&2 on amp

Low RCA from radio to channel 3&4 on amp

Bridge channels 3&4(no lower than 4ohms) for sub use.

 

[dweLz 10+ year member]

awesome man thanks.I just got confused because the manual says something about a Y-connector

 

[Databyter 10+ year member]

According to the manual on this particular Amp, you are correct in what you said above, that you can only use ONE of the rear stereo channels to feed into the inputs of channel 3 and 4 on the Amp.

I only have 2 RCA outputs to work with from my head unit.
I think I am only supposed to use one of the RCA's and split it into two to get a mono signal.

If you combine them the circuitry of this Amp will work against itself.

This is based on the Manual's instructions.

It seems sort of limited but I would trust the manual more than offhand opinions based on how most other Amps might work.

Some other Amps offer the ability to fix the issue internally, and with switching, so you can just connect up.

But if I remember correctly the low frequencies in most recordings like those that go to your subs are the same on both stereo channels anyway for the most part.

Your user manual clearly shows one channel from the stereo source not being used if you have no mono (sub channel) out from your HU.

If you don't think your getting all the low end signal using this method you'l have to get a different amp or a headunit that has a mono or sub out.

For those that need to see the black and white I give you this link http://www.retrevo.com/support/MB-Quart-DSC4125-Car-Amplifiers-manual/id/23608ag900/t/2/

 

[dweLz 10+ year member]

My HU actualy has a 3 sets of RCA outs,one being a sub out.In that case should i go ahead and do as RyanM923 suggested? Im so confused lol.