# Bridging this Alpine PDX 4.100



## rjcastr (May 17, 2007)

Hey guys im trying to get more punch out of my midbass how would you bridge this amp to get 200 watts rms please help, even by looking at this thing im not so sure how.


rj


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## alphakenny1 (Dec 21, 2005)

check your manual. it should tell you how to bridge the amp.


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## Locke (May 29, 2007)

look at the other panel, try the switch that says, 1+3/2+4 and use the 3/4 inputs, turn the x-over on channels 1 and 2 off, use the gain for 3 and 4 ect. not sure but thats what I get looking at it


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## Lightninghoof (Aug 6, 2006)

The manual is very vague on how to bridge, took me awhile to figure it out. 

If bridging channel 3 & 4, use the (+) of channel 3 and the (-) of channel 4. The manual states that Y-splitters are required when bridging if stereo separation is required. It shows you in a little picture at the bottom of the page under the section about 3-speaker mode.


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## Locke (May 29, 2007)

Lightninghoof said:


> The manual is very vague on how to bridge, took me awhile to figure it out.
> 
> If bridging channel 3 & 4, use the (+) of channel 3 and the (-) of channel 4. The manual states that Y-splitters are required when bridging if stereo separation is required. It shows you in a little picture at the bottom of the page under the section about 3-speaker mode.


 good eyes it is a very vague manual in that respect


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## rjcastr (May 17, 2007)

four wires in 2 speakers

+ - + -


how can i connect 4 wires two in to two channels?


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## rjcastr (May 17, 2007)

Lightninghoof said:


> The manual is very vague on how to bridge, took me awhile to figure it out.
> 
> If bridging channel 3 & 4, use the (+) of channel 3 and the (-) of channel 4. The manual states that Y-splitters are required when bridging if stereo separation is required. It shows you in a little picture at the bottom of the page under the section about 3-speaker mode.


is it both positives in to channel 3 + and both negatives under channel 4 -??


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## Lightninghoof (Aug 6, 2006)

Nope, the little picture in the manual shows you how to do it. (+) of Channel 3 and (-) of Channel 4 only. Same thing applies to Channel 1 and Channel 2.

Make sure you hook up the RCA's properly, this amplifier was designed to be used with RCA splitters if running separate signals to each speaker. (stereo)


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## rjcastr (May 17, 2007)

ok now im really lost what does the signal have anything to do if im bridging for power

im trying to get 200 watts rms out of these babies. I really need to learn more about this sutff


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## ddriggers2 (Dec 26, 2005)

rjcastr said:


> ok now im really lost what does the signal have anything to do if im bridging for power
> 
> im trying to get 200 watts rms out of these babies. I really need to learn more about this sutff


Yeah, I am lost too. I dont see anything in the diagram that would suggest splitting the signal.


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## Locke (May 29, 2007)

Important Tips on Bridging an Amplifier

NOTE:
The following troubles may occur when it
is not properly connected.
1) One side input results in low output.
2) One side input will cause failure.
3) One side input may cause more
heating and thus result in the earlier
operation of overheating protection


there is a picture to at the bottom of the PDF, shows the splitter's, but I am with you guys still not quite clear in the manual, you would also think you could use the input switch in the front panel to avoid using the y-splitters?


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## supra400hptt (Aug 11, 2005)

I did a search and came up with this. I'm trying to figure out how to bridge a 4.150. I've came to the conclusion that RCA Ys are needed to keep it stereo. The diagram shows how to bridge when wanting to run a sub. It looks like the two channels are summed. For stereo (bridging to run my midbasses), has anyone got the answer to this before I call Alpine. What should the selector be set to, how are the speaker wires connected and how should the two Ys be plugged in? The manual doesn't show how to bridge for stereo. Thanks.


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## LiquidClen (Dec 27, 2005)

I'm confused as to why Y-Splitters would be needed for stereo


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## supra400hptt (Aug 11, 2005)

Ok, I went and took a look at the owners manual to an Alpine MRP 4 channel amp. There is a diagram on bridging for two speakers and I assume it keeps things stereo. Instead of trying to explain it and add to any confusion, take a look at it. I'll try hooking things up like that this weekend.


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## 328iBMW (Aug 16, 2007)

So you want your woofers running in mono in order to get a little more power?


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## FoxPro5 (Feb 14, 2006)

Yea that's Alpine and their damn input selector switch. IIRC after having a few of their amps you want the 1+2/3+4 position.

Best way to do it is just hook everything up and listen. No Y splitters needed as the switch summates for you. I think Alpine even states that's one of the purposes of the switch in the first place.

From the manual:

Input Channel Selector Switch
a) Setting this switch to “1 + 3/ 2 + 4” will sum
the CH-1 and CH-3 input and send it to
CH-3 while the CH-2 and CH-4 inputs are
summed and sent to CH-4.

b) Set this switch to “3/4” to have the inputs of
CH-3/4 accept independent input signals.
An example of this application would be
the use of a head unit with dual pre-amp
outputs.

c) Setting this switch to “1/2” will send the signal
at the inputs of CH-1/2 to CH-3/4 of the
PDX-4.100. This eliminates the need for
“Y”-adaptors when using a head unit with
a single pair of pre-amp output.


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## Abaddon (Aug 28, 2007)

FoxPro5 said:


> Input Channel Selector Switch
> a) Setting this switch to “1 + 3/ 2 + 4” will sum
> the CH-1 and CH-3 input and send it to
> CH-3 while the CH-2 and CH-4 inputs are
> summed and sent to CH-4.




Yes, but even in this mode, you still need input to all FOUR of the RCA's

So your headunit / processor will have a single set of pre-outs set for this pair of speakers you are running. You then need to split the signal so that you have 4 RCAs to input into the PDX amp.


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## FoxPro5 (Feb 14, 2006)

Abaddon said:


> You then need to split the signal so that you have 4 RCAs to input into the PDX amp.


I'm not 100% sure but I don't think so.

If you want to bridge the amp to your midbasses, for example:
Left RCA (left midbass) ---> CH-1 or CH-3
Right RCA (right midbass) ---> CH-2 or CH-4

Since you only have two channels (two RCA leads) and the amps takes whatever is on CH1 and sends it to CH3, it really shouldn't matter. Same thing for CH2 and CH4. 

On the back of my 4.150 it shows (L) above the CH-1 and CH-3 inputs and (R) above the CH-2 and CH-4 inputs. So this tells me the amp is split L to R according to the input selector switch.

Now comes the part about hooking up the speakers. It seems you should just use the +/- on CH3 and hook your Left midbass up to it; CH4 for Right midbass?? I don't remember now how it worked on the old ones.

Seems the guy that wrote the review on the 4.150 for CA&E was stumped on it too:



> My single biggest beef with this whole idea is that I found it difficult to determine how to bridge the channel pairs from the instructions. You will connect the positive wire to only the positive side of one connector, and the negative speaker wire to only the negative side of the other connector for the channel pair. But now, which jacks do you plug them into? For the record, the odd channels (1 and 3) will use the positives, but I determined this by finding out which were the active outputs from the amp. It's not mentioned in the owner's manual. If you plug yours in and get no output, just reverse your connectors.


If this is incorrect, someone please correct me because I have a massive headache!


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## Abaddon (Aug 28, 2007)

To hook up the speakers:

Positive from Channel 1
Negative from Channel 2


Positive from Channel 3
Negative from Channel 4


I know this, because I just tried it.


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## FoxPro5 (Feb 14, 2006)

Abaddon said:


> To hook up the speakers:
> 
> Positive from Channel 1
> Negative from Channel 2
> ...


With the selector switch at 1+3/2+4 ???

I suppose you could also use Y's and set it to 3/4? No??


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## Abaddon (Aug 28, 2007)

FoxPro5 said:


> With the selector switch at 1+3/2+4 ???
> 
> I suppose you could also use Y's and set it to 3/4? No??


well I didn't bridge all of the channels at once..

I had the switch on 3/4 and bridged channel 1 and 2 with RCA's running to them.. then moved the RCAs to channels 3 and 4 and bridged those...


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## FoxPro5 (Feb 14, 2006)

For those of you running the amp full range (not bridged, just all 4 ch in stereo) where did you put the put the selector button??


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## michaelsil1 (May 24, 2007)

FoxPro5 said:


> For those of you running the amp full range (not bridged, just all 4 ch in stereo) where did you put the put the selector button??


3/4.

I have my PDX 4.150 bridged and I'm using Y splitters, its set at 3/4.


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## ninor (Jan 8, 2009)

Bump to an old thread... I have PDX 4.150 and I know how to bridge it but I'm really confused on the RCA cables part... I am using 4 channel RCA cable for my fronts and 4 RCA plugs are in head unit in front and rear preouts and I am not sure where to put them in the amp... any help would be appreciated.


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## Fiercetimbo17 (May 17, 2007)

I did not use any y splitters when i had my pdx's bridged.
I believe i used the 1+2/3+4 switch
Speaker wires were channel 1 had the positive channel 2 negative and so forth.
Then RCAs were white on channel 1/2 input red on channel 3/4


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## qstarin (Mar 25, 2009)

Hmm... I just tried this and I'm having trouble.

Left front output from the HU is Y-split into input channels 1 & 2.

Right front output from the HU is Y-split into input channels 3 & 4.

+ from ouput channel 1 and - from ouput channel 2 is wired to front left speaker.

+ from output channel 3 and - from output channel 4 is wired to front right speaker.

I quadruple checked those connections.

Tried with the input switch on 3/4 & 1/2 (not 1 + 3/2 + 4 because that doesn't make any sense for bridged.


If I turn the volume up more than half way the front speakers cut out and stay out for around 30 seconds, then they come back on.

The amp is not showing any failure (the light is blue, not red) and is not warm.


The amp was working perfectly in 4 channel mode, and I removed the rear speakers and tried to bridge to the front channels.


Anyone got any ideas?

I've got it hooked up just like the instrucions, except I'm bridging both sets of channels instead of just 3 & 4.


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## qstarin (Mar 25, 2009)

Hmmm .... well, it looks like I may have fried my front components (possibly with test tones), and the amp's kicking off (despite showing no protection lights).

That appears to be my problem with bridging, especially since now its happening un-bridged and only on the right front channel, whose tweeter sounds like dirty a** all of a sudden.


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## rynakus (Nov 15, 2008)

I paid Car Toys to bridge mine, and they used Y splitters, but the channel setting has no effect on sound. I can switch it to 1+3 2+4 or whatever the choices are and there is no change in sound. 

Also, anyone have any idea why one mid would distort at higher levels? My drivers side turns to crap, but my passenger side keeps on jammin at any level. I have played with the xover, the gains, the filters, everything. I have to keep it at HP and over 160 to keep it from distorting.


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## JAYGOW1 (Jul 6, 2009)

All so confusing !!


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## Technic (Oct 10, 2008)

Same procedure: http://www.diymobileaudio.com/forum/729725-post2.html


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## Eliot (Jan 3, 2010)

Any sub recommendations for a three speaker set up on pdx 4.100? I will be running 2 Boston sl95 6x9's and have room for one 8" sub, not sure how many watts this amp produce on rear channel bridged? By the way this will be on a Harley with the sub in the one bag, I want it to be an effecient sub, not to power consuming. Thanks in advance!


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## chipss (Nov 13, 2009)

ya dont like the v-twin music? lol
if it were me, I would think an 8' a bit large even in u-classic bags, may fit in them old springer bags? what bags are they?
if you intend to put amp and speaker in one bag your airspace for that speaker is just about gone, just off the top of my head, I would look into a good 6.5 driver like the cdt m-6, or some shallow mount types. but the first step would be finding out how much airspace you have left in that bag after displacment of the speaker and I am asuming the amp as well....run the numbers, see whats left, find a driver close to that, or have a sound shop do it....to give you an idea what will fit airspace wise and make best use of the driver...now where is that raingear, jacket gonna go? lol...
but then again I took off my bags, windshild, and gps, and just enjoy the fact...its a classic motorcycle, the music is in the motor....






Eliot said:


> Any sub recommendations for a three speaker set up on pdx 4.100? I will be running 2 Boston sl95 6x9's and have room for one 8" sub, not sure how ma dany watts this amp produce on rear channel bridged? By the way this will be on a Harley with the sub in the one bag, I want it to be an effecient sub, not to power consuming. Thanks in advance!


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## Eliot (Jan 3, 2010)

That was a good one!! Thats what my father in law said! Plan is to have one bag with sub, other with amp. I will do the math on the volume, that is good advise. Still not sure what the watt rating is for the one side bridged? Appreciate the advice! EE


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## chipss (Nov 13, 2009)

200 bridged mono and 100/2 for the other side


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## Eliot (Jan 3, 2010)

Thanks Chipss, now just figure which sub is the most efficient out there and I should be good to go! I will keep you posted on the system. I hope to have everything done for spring riding. Its going into paint next week. Its an 05 Road King Custom, going old school. I'll post some pics later. Eliot


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## crzygosu87 (Dec 1, 2010)

Bringing a thread back to life regarding bridging an alpine pdx 4.100. I saw this thread a while ago but never got around to actually installing my components until now (ID ctx65cs) ... however since this thread still didn't seem to answer my question concretely, I went ahead and called alpine support. This is what they informed me in case anyone is still wondering and comes across this thread like I did:
________________________________________________________________
Left input > Y-adapter > Channels 1 and 2
Right input > Y-adapter > Channels 3 and 4

Left: Ch1 +, Ch2 -
Right: Ch3 +, Ch4 -

Input Channel Selector Switch --> Set to "3/4" option
________________________________________________________________

Hope this helps someone in the future since it sure created a headache for me lol. Then again ... I am kind of a noob to car audio (just starting to get into it. Might consider going active in the future as well )

EDIT: I'll be giving this a try right now


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