pdx 4.100m bridging

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=132630
Printed Date: May 13, 2025 at 12:41 AM

Topic: pdx 4.100m bridging

Posted By: steveco
Subject: pdx 4.100m bridging
Date Posted: November 10, 2012 at 9:02 AM

up for discussion.
input switch set at 1+3/2+4
input #1 & #3-left channel-y connector
input #2 # #4-right channel-y connector
therefore speaker output connections for 2 speaker connection @ 200w 4 ohms is
ch1+ ch3- & ch2+ ch4-
now it is in stereo and the left/right balance function works properly on the deck

Replies:

Posted By: steveco
Date Posted: November 10, 2012 at 1:00 PM

alpine pdx-4.100m

Posted By: DYohn
Date Posted: November 10, 2012 at 1:40 PM

What would you like to discuss?

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Posted By: steveco
Date Posted: November 11, 2012 at 8:44 AM

this topic on the alpine pdx amplifiers was discussed a few years ago on this forum site and i noticed it was a really grey area as to the connection of the inputs between the alpine head unit and the pdx-4.100 amp and the position of the input switch.
also i noticed there was frustration as to the speaker output connections when bridging the speakers when connecting them to be a 200w/4 ohm load.
i spoke with 5 different alpine tech support personal and each one had a different answer so i thought this topic could be resurrected as i have just purchased the alpine pdx-4.100m and experiencing the same dilemma.
in my first post above i wrote what i think is the proper connections for bridging an alpine amp and seems to be working. any other method of connection and the balance control on the head unit does not work properly. there was always music coming out of both speakers when the balance control was set at extreme left or right. my diagnosis is after many hours of experimenting and phone calls to alpine tech support with no consistency from phone call to phone call. if i had the schematics of the internal wiring of the amplifier then i could be more sure.
i look forward to other posts and replies.

Posted By: soundnsecurity
Date Posted: November 11, 2012 at 10:48 AM

steveco wrote:

up for discussion.
input switch set at 1+3/2+4
input #1 & #3-left channel-y connector
input #2 # #4-right channel-y connector
therefore speaker output connections for 2 speaker connection @ 200w 4 ohms is
ch1+ ch3- & ch2+ ch4-
now it is in stereo and the left/right balance function works properly on the deck

so you are saying that the balance doesnt work when you have this amp set up to use channel 1 &2 as the left speaker and channel 3&4 as the right speaker? ive never seen an amp that needed to be bridged from channel 1 to channel 3 in order to work. are you using RCA's or some other type of input method?

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Posted By: steveco
Date Posted: November 11, 2012 at 1:53 PM

the key is to have the two speakers connected as i mentioned: left speaker ch1+ & ch3-, right speaker ch2+ & ch4-. the alpine tech said to use a y-connector on input ch1 & ch3 (left) and a y-connector on ch2 & ch4 (right), then set the input switch to 1+3/2+4

Posted By: i am an idiot
Date Posted: November 11, 2012 at 8:46 PM

Input switch set to 1 and 2. One speaker connector in channel 1, and the other connector in channel 3. There is a switch inside connectors 2 and 4. If there is nothing plugged into them, the right negative signal is sent to the negative on connectors 1 and 3.