Can we bridge the factory amp???

6086 Views 12 Replies 8 Participants Last post by Yoda E SC, Aug 22, 2011

gstyper

Discussion Starter · May 27, 2003

Does anyone know if we can take the oem amplifier and bridge the channels into 2. What I want to do is use the oem amp to power the rear speakers. I have a new amp to power the front components. Any help would be greatly appreciated. :?

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samwise801

· #2 · Aug 17, 2011

Anybody ever find an answer to this question? I'm betting the answer is no, but it sure would be nice...

Here's to resurrecting a really, really long-lost thread. Cheers!

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AztecRol

· #3 · Aug 17, 2011

samwise801 said:
Anybody ever find an answer to this question? I'm betting the answer is no, but it sure would be nice...

Here's to resurrecting a really, really long-lost thread. Cheers!

First, major props for doing a search and finding a thread that was already
started for the question you have!!!

Second, you are the winner of the "who resurrected the oldest thread" contest!!
8 years and 3 months!!!!

An amp can not be bridged unless it was built to be bridged. ALL amps that can
be bridged, will have a switch on them with another wiring diagram that shows
how to hook up the speaker as well as what input to use when the amp is
bridged. I dont think there is ONE OEM amp from a car manufacturer that can
be bridged. OEM amps are built for one purpose. They are not built to be
expandable or future proof.

Here is a pic of the back of one of my Adcom Amps that can be bridged:

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samwise801

· #4 · Aug 17, 2011

Yeah, I figured as such -- just thought I'd check and see if anyone out there has ever tried this crazy idea. (Probably fried something if they did, but it's worth a shot eh?)

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Grendel0501

· #5 · Aug 19, 2011

AztecRol said:
An amp can not be bridged unless it was built to be bridged. ALL amps that can
be bridged, will have a switch on them with another wiring diagram that shows
how to hook up the speaker as well as what input to use when the amp is
bridged.

Not all bridgeable amps have switches, most 4ch's have the switches you speak of. 2/3/4ch modes, but those control how the signal is sent to the channels, not how the amp sends the power.

How the amp sends the power, is decided by which inputs are wired and which are left unwired. Look at a 2ch amp for a example, 2ch's bridgeable to 1ch, but no switch to switch from 1 to 2ch.

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angus5

· #6 · Aug 19, 2011 (Edited)

Yes^^^ -in fact most car amps these days have no switch for bridging, just hook up speakers differently. I think you could simply try bridging it - you'll need to try different combos of skeaker wiring - you'll know when it's right since it'll be way louder - worst case you blow it up - but I kinda doubt it - probably just either sound like crap or shut down.

If it's just for rear fill you could just run 2 CH.

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racerc2000

· #7 · Aug 19, 2011 (Edited)

its doubtful the oem amp is stable for bridged. electronics start to smell on agressive songs at 24 volume. with a conservative bass setting. most songs its fine but some its not

my guess is the heat sinks are inadequate,power wires too small etc etc.

if you could find one. get the schematics for the amp. I used to upgrade my old computer speaker amps. klipsch ultra 5.1s better resistors and capacitors and heat sinks to be stable at higher levels.

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Grendel0501

· #8 · Aug 19, 2011 (Edited)

Even if you could bridge the factory amp, it would have to be 2ohm stable per channel.
Otherwise you wouldn't be able to bridge for a final 4ohm load, it would be a 8ohm load, and connecting a 4ohm speaker (99% of interior speakers) would damage the amp.

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AztecRol

· #9 · Aug 19, 2011

Grendel0501 said:
Not all bridgeable amps have switches, most 4ch's have the switches you speak of. 2/3/4ch modes, but those control how the signal is sent to the channels, not how the amp sends the power.

How the amp sends the power, is decided by which inputs are wired and which are left unwired. Look at a 2ch amp for a example, 2ch's bridgeable to 1ch, but no switch to switch from 1 to 2ch.

Im from the home audio world. I havent done anything with car audio in years.
Im not sure how an amp can tell if its in normal mode or bridged mode?? What
amps are you talking about?? I'd like to do some research on them. Im guessin
that they are all digital/chip amps?? The amps Im used to are solid state. Im
not sure you could bridge one without a switch to change the internal wiring.

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Grendel0501

· #10 · Aug 21, 2011 (Edited)

I've dabbled in car audio for the last 10years, but I'm by no means a professional. So the exacts of how it works are greek to me.
Something about how the amp is wired internally, with each set of bridgable channels being connected in a way that if one speaker is wired with a specific + from one ch and another specific - from the other channel it then automatically sends all the power through those channels.
My guess would be that each set of bridgeable channels are wired internally in series with a second set of channels, that when wired change the internal wiring to parallel.

Pick ANY 2ch mobile amp, I just went and looked at 3 different brands and all bridgeable 2ch's didn't have a switch. What they do all have is a wiring diagram which shows which two ch connections to mix to acheive bridged wattage.

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Audiophyle

· #11 · Aug 21, 2011

Many chip amps cannot sustain low impedances, and are designed differently than a traditional fet powered amp. I have an amp from PG that is a 6ch chip amp, and it can only sustain 4ohm on each channel and cannot be bridged at all.

You want the facts on how bridging an amp works?
http://www.bcae1.com/bridging.htm

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angus5

· #12 · Aug 22, 2011

^^^Just like your signature says...

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Yoda E SC

· #13 · Aug 22, 2011

The "amp" inside the factory amplifier that handles the 4 channels for the 6 1/2's and the tweeters is a typical TDA series chip "amp" and cannot be bridged. sorry.

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