Print Page | Close Window

Bridging and Checking

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=13432
Printed Date: June 23, 2025 at 9:41 PM


Topic: Bridging and Checking

Posted By: MisterE
Subject: Bridging and Checking
Date Posted: May 11, 2003 at 7:28 PM

Ok if I have a JBL GTQ400 that is a 4 channel amplifier rated at 75 watts per channel at 4ohms.
And can be bridged to two channel rated at 200 watts per channel at 4ohms.

Can this be used one a Dual 2-ohm VC Brahma sub? Could I use each of the bridged channels on each voice coil? The amp needs a 4-ohm load, but i dont know if using both of the 2 ohm voice coils would do it.

I definitely dont know how to wire it. I know how to wire series and parellel to DVC subs, but not how to wire 1 channel to each voice coil, any help? Thanks



Replies:

Posted By: esmith69
Date Posted: May 11, 2003 at 8:03 PM

I started to write out a bunch of stuff but then realized that it's gonna be pretty tough for you to do much with this combination.  If it were a 2-channel amp it'd be perfect cuz you could wire up the two 2-ohm voice coils in series, and that'd give the amp a single 4-ohm bridged load.  The problem is that I don't think your 4-channel amp can handle two 2-ohm bridged loads.  That's essentially what you'd be doing if you bridged the front channels of the amp to run one voice coil, and bridged the other two channels to run the other voice coil.

The amp is most likely 2 ohm STEREO capable which means you could run both voice coils off of the 2 front channel speaker outputs, but to do that you'd need to be getting a mono signal from the head unit as both channels need to get the EXACT same input signal for the sub to play properly.  Many headunits have sub preouts but most of them send a stereo signal, and not a mono signal.  Find one with a mono signal, and I think you could make it work.  You'd really only be able to use about half of your amp's available power output though.



-------------
Ethan
-----
"Patience, persistence, and perspiration make an unbeatable combination for success"
Donate to the12volt.com




Posted By: Big Purds
Date Posted: May 12, 2003 at 3:31 PM
esmith is right...and that amp running at half power is NOT enough power to drive a Brahma very well at all...





Print Page | Close Window