# Alpine PDX - Dumb Question



## txbonds (Mar 10, 2008)

*Question 1*
Okay, I've searched high and low and am just not finding any thing clear on this. The manual is very ambivalent as well.

How do you know which is positive and which is negative on the speaker connections? The speaker wire terminal plugs are marked + / - very clearly, but they are not polarized and will plug into the amp in either direction.

My pdx-5 simply has wording over each speaker spot indicating the channel, and then has a little diagram with + @ - The @ represents a funny symbol like a backwards "C" with a dash in it. Nothing like that on my keyboard.

Anyway, if that is written horizontally over a socket that runs vertically, how do I know if positive is on the top or the bottom of the socket?

The manual simply states the plug isn't polarized and can be used either way, but to keep my phasing straight I'd like to know which is which.

Anyone know?



*Question 2*
I've run 4 gauge from battery to fuse block, and 8 guage from fuse block to about a 3 foot run to amp. The book says use 4 guage into amp, and the amp is fused at 60 amps. Am I okay to drop to 8 guage, or should I go back up to 4? Just curious as I figured 8 was okay on this short of a run, but wanted opinions.


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## TheDavel (Sep 8, 2006)

I am not sure and have always wondered, but I always place the + side towards the top of the amp...


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## Andy Jones (May 12, 2006)

1. I believe Postive is on top, but if in doubt, plug it in and use a polarity checker.

2. For that length of run of 8 ga you should be fine.


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## ErinH (Feb 14, 2007)

IIRC, the manual itself states that the position doesn't matter; just that you make sure to use the correct 'terminal' by it's marking. Make sense?


8 gauge should be fine. In fact, 8 gauge is much easier to fit in the terminals. I used 4 gauge and had to strip back some wiring. If I hadn't been working on it on a Sunday I would've gone to the local shop and bought 8 gauge.


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## txbonds (Mar 10, 2008)

I was hopeful someone with an electronics background was going to pop up and tell me that the way it is written with the funny backwards C symbol thing was some industry standard way of doing it and meant that the positive was on top for that reason. LOL

Right now, I have Positive on top also. Thanks.


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## txbonds (Mar 10, 2008)

bikinpunk said:


> IIRC, the manual itself states that the position doesn't matter; just that you make sure to use the correct 'terminal' by it's marking. Make sense?



Thats exactly what the manual says, and it indicates you can flip the plug either direction as in it's not polarized. Problem is, the + and - prongs are separate inside that plug, so unless the amp is somehow auto sensing the polarity, it would matter from the stand point of phasing. make sense?


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## t3sn4f2 (Jan 3, 2007)

4 prongs, middle 2 is one polarity outer 2 is the other, flip the plug either way and you will always get the same thing. So + is always + and - is always -.


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## txbonds (Mar 10, 2008)

t3sn4f2 said:


> 4 prongs, middle 2 is one polarity outer 2 is the other, flip the plug either way and you will always get the same thing. So + is always + and - is always -.


Ah Ha. That damn well explains it. Thank you. I didn't realize that outer ring was part of the connection. Thought only the inner two were, which was causing my confusion.

Thanks so much for clarifying what the manual doesn't say quite so clearly.


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## BEAVER (May 26, 2007)

So PDX users cant reverse their polarity for tuning?


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## ErinH (Feb 14, 2007)

You can. Just switch your wires in the terminals. Put the - in the + and vice versa. Or do it at the speaker.


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## txbonds (Mar 10, 2008)

Right. It isn't as easy as flip flopping the plug unfortunately, but no more difficult than changing them on any other amp. As bikin said, just change them in the plug based on the information provided by t3sn4f2.

I'm thinking the 800prs allows changing of phase from the head unit though, right? If so, I'm wanting all hard connections done and then flip phase electronically if needed.


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## t3sn4f2 (Jan 3, 2007)

Slight correction:

Squeeze me, its 2 prongs, same results though. Outer perimeter contact is negative, inner one is positive. Turn them, you get the same thing. Sorry bout that, shoulda looked closer :blush:


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## txbonds (Mar 10, 2008)

t3sn4f2 said:


> Slight correction:
> 
> Squeeze me, its 2 prongs, same results though. Outer perimeter contact is negative, inner one is positive. Turn them, you get the same thing. Sorry bout that, shoulda looked closer :blush:


No problem. Still same result. The center one looks split. Never thought to check continuity between negative/positive wiring spot and the contacts on other side of plug, as that would have confirmed what you are telling us.

Thanks again.


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## txbonds (Mar 10, 2008)

t3sn4f2 said:


> Slight correction:
> 
> Squeeze me, its 2 prongs, same results though. Outer perimeter contact is negative, inner one is positive. Turn them, you get the same thing. Sorry bout that, shoulda looked closer :blush:


Holy cow............... I'm an idiot. Why didn't I see it this way the other day. That funny backwards "C" with the dash in it represent the damn plug. The Postive is the center part, and the negative is the outer part. Doh!

Thanks again..........


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## t3sn4f2 (Jan 3, 2007)

txbonds said:


> Holy cow............... I'm an idiot. Why didn't I see it this way the other day. That funny backwards "C" with the dash in it represent the damn plug. The Postive is the center part, and the negative is the outer part. Doh!
> 
> Thanks again..........


Anytime....


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## TheDavel (Sep 8, 2006)

I'll admit... I have never looked that closely at the drawing on the amp either and I have had over a dozen of them in my own cars


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## legend94 (Mar 15, 2006)

t3sn4f2 said:


> 4 prongs, middle 2 is one polarity outer 2 is the other, flip the plug either way and you will always get the same thing. So + is always + and - is always -.


Thank you!

Googled alpine pdx polarity and was happy to find This answer so quickly.


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## therapture (Jan 31, 2013)

Wow - I never noticed this either, and I was always trying to make sure I had all the plugs lined up the same! I even swapped directions on the sub plug a couple times and was wondering why the hell I was having trouble telling a difference in sound.

the internetz is awesome


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## oabeieo (Feb 22, 2015)

txbonds said:


> *Question 1*
> Okay, I've searched high and low and am just not finding any thing clear on this. The manual is very ambivalent as well.
> 
> How do you know which is positive and which is negative on the speaker connections? The speaker wire terminal plugs are marked + / - very clearly, but they are not polarized and will plug into the amp in either direction.
> ...


You lookin the speaker terminals the parts that in plug they are marked positive and negative you can insert it any way in the amp it doesn't matter the center post I think is positive and the outer shield is negative, you can't screw it up its a circle. They designed it so you can plug it in either way the polarity can't change if you plug it in upside down cause terminals are circular. 2 I would use 4ga 8 ga is only good to 600w you could get away with it I'm sure but I would use four because the sub channel alone is 500w imo


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## txbonds (Mar 10, 2008)

oabeieo said:


> You lookin the speaker terminals the parts that in plug they are marked positive and negative you can insert it any way in the amp it doesn't matter the center post I think is positive and the outer shield is negative, you can't screw it up its a circle. They designed it so you can plug it in either way the polarity can't change if you plug it in upside down cause terminals are circular. 2 I would use 4ga 8 ga is only good to 600w you could get away with it I'm sure but I would use four because the sub channel alone is 500w imo





Whew, thank goodness For your response. I've been sitting idle on my install trying to get this answered. 













Just kidding. Thanks but I asked that nearly 7 years ago. Amp has been long, long gone since then. Maybe helps the next person though. LOL.


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## legend94 (Mar 15, 2006)

It helped me with a pdx v9! This is an example of searching instead of making a new thread


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## t3sn4f2 (Jan 3, 2007)

Not that it changes anything, but I'm still not sure exactly how the pin layout is on the rotating plug? Is it negative gold shield on the perimeter and two or three positive connectors in the center connector? Or is the outside just a hard metal piece to protect the plug, keep a tight connection, and has no electrical connection whatsoever. Then the center is a three prone negative-positive-negative? Or something else all together?  

Again though, the plug connection is not polarized.

Has anyone run a continuity test on the plug to see exactly what the pin designation is?


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## sirbOOm (Jan 24, 2013)

In summary, it doesn't matter - so long as you orient the plugs the same for all speakers.


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## gijoe (Mar 25, 2008)

sirbOOm said:


> In summary, it doesn't matter - so long as you orient the plugs the same for all speakers.


It sounds to me that you don't have to orient the plugs at all, as long as you have the positive wire in the positive part of the plug. If the wires are secured to the plug correctly you can turn half of the plugs upside down and it won't make a difference at all.


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## Babs (Jul 6, 2007)

sirbOOm said:


> In summary, it doesn't matter - so long as you connect the + and - speaker leads to the correct + and - posts on all connectors.


Fixed, Sir. 

As I've acquired an F4 unexpectedly, I'm rather thrilled about this cool little feature. Makes plug up a breeze. Now to acquire more such deals, and stack'em up. 

SirbOOM, you've sold all your PDX's you were offering, haven't you?


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## arsus88 (May 2, 2015)

The amp is a great amp because it delivers adequate power for four channels plus a sub. I bought a new pickup and it had no bass, so I bought this amp and a sub. It was more than adequate without overdoing it and not outrageously loud. I'm not a kid who needs 2000 wats of power but this amp is perfect. Plus, the compact size was perfect for fitting underneath the passengers seat.


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## JohnKuthe... (Nov 2, 2016)

TheDavel said:


> I am not sure and have always wondered, but I always place the + side towards the top of the amp...


My convention too.  Plus is on top, the wire with the writing/stripe, etc. Remember for speakers it's just to be sure all speakers are in phase with each other. The speaker signal is A/C!

I think they are reversible so you can physically invert the phase on any speaker at will, easily.

John Kuthe...


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## JohnKuthe... (Nov 2, 2016)

txbonds said:


> I was hopeful someone with an electronics background was going to pop up and tell me that the way it is written with the funny backwards C symbol thing was some industry standard way of doing it and meant that the positive was on top for that reason. LOL
> 
> Right now, I have Positive on top also. Thanks.


I'm an Electrical Engineer by degree, and I can tell you definitively the polarity on speakers is just for reference to be able to insure all speakers are in phase with each other.

Backwards C? Dunno.

John Kuthe...


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## lizardking (Nov 8, 2008)

I thought the same when I first started using the amps. Then I was trying to figure how to bridge it. Realized doesn't matter.


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## Justin Zazzi (May 28, 2012)

If we're going to resurrect discussions from eight years ago, lets do it right! 

It is a little ironic that the intention was to create a fool-proof connector that can be inserted any which way and still work properly, but it ended up creating some confusion.

The backwards C-shaped symbol indicates which part of the circular connector on the alpine amplifier is positive and which part is negative. In this case, the center is positive and the "ring" or outer conductor is negative. The neat thing about these connectors is you can insert them facing any which way you like, and because of the circular symmetry, the polarity relationship doesn't change (this is exactly what is happening with the new version of USB connectors, thank the gods). So as long as you connect the positive speaker wire to the socket on the connector with the positive "+" symbol next to it, then you're good. You can insert the connector to the amplifier with the positive wire near the top or near the bottom and it will not matter.

The 2nd photo is a little easier to see all this, and I left it not marked-up so you can see it better.

You will also find this backwards C-shaped symbol on other circular connectors such as a power adapter for almost every electric device out there. This is shown in the third photo.


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## JohnKuthe... (Nov 2, 2016)

Jazzi said:


> If we're going to resurrect discussions from eight years ago, lets do it right!
> 
> It is a little ironic that the intention was to create a fool-proof connector that can be inserted any which way and still work properly, but it ended up creating some confusion.
> 
> ...


Excellent pics! Thanks! Took them yourself, I'm imagining?Although I still can't figure out where the connections are! RCAs are easy, these things are confusing as h e l l! 

And what about where would I put the two leads of a VOM to measure the impedance of the speaker+wire? VERy confusing, I was trying and found nothing good. 

John Kuthe...


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## Justin Zazzi (May 28, 2012)

JohnKuthe... said:


> Excellent pics! Thanks! Took them yourself, I'm imagining?Although I still can't figure out where the connections are! RCAs are easy, these things are confusing as h e l l!
> 
> And what about where would I put the two leads of a VOM to measure the impedance of the speaker+wire? VERy confusing, I was trying and found nothing good.
> 
> John Kuthe...


Heh, thanks. I borrowed those pictures from whoever took them, but I marked them up with the green stuff myself 

To measure the impedance of a speaker plus the wire it is attached to, you would need to build a voltage divider and take a few extra steps. You can do this at various frequencies and use the data to calculate the Thiele/Small parameters as shown on this page: Measuring Loudspeaker Driver Parameters (also shown on that page is the voltage divider and measurement setup)

If you want to measure the DC resistance of the speaker's voice coil and the speaker wire, then unplug the black Alpine speaker connector from the amplifier and put your test probes into the slots where the wires go into the connector. You should be able to contact metal without too much trouble from what I remember when I installed mine.

If you're talking about which pins to probe from the side of the Alpine connector that attaches to the amplifier, then you will have to use a continuity test (or ohms setting) on your multimeter to see which pin goes where. I haven't tried it, but I think the center three pins are positive and the outer solid ring is negative.


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## JohnKuthe... (Nov 2, 2016)

Jazzi said:


> Heh, thanks. I borrowed those pictures from whoever took them, but I marked them up with the green stuff myself
> 
> To measure the impedance of a speaker plus the wire it is attached to, you would need to build a voltage divider and take a few extra steps. You can do this at various frequencies and use the data to calculate the Thiele/Small parameters as shown on this page: Measuring Loudspeaker Driver Parameters (also shown on that page is the voltage divider and measurement setup)
> 
> ...


This is stupid!! Alpine made a very simple thing and turned it into a neo-technological nightmare!! I'm not talking about response spectrum analysis, I'm talking about using a VOM to make a quick, easy and reasonably accurate electrical assessment of a speaker+wire's patency, i.e. is this speaker electrically viable, e.g. is it's DC resistance 0 (shorted out), infinite (open circuit) or the nominal normal case of just a few Ohms!

This is just another example of taking a years old basic electrical assessment and obviating it into oblivion!! I don't want to have to trey and wedge my VOM probes into the juncture between the wire and the plug to get to the wire's conductor!! A few of these and your wiring job's gonna look like c r a p! I guess I'll just have to grab my little tiny Allen/hex wrench, remove the set screws and pull the bare wire out of the plug to make a very simple electrical status! Then replace the wires into the plug and tighten the set screws again!! Again a matriculation which is gonna screw up stuff eventually! :-(

I HATE too advanced technology! :-(

John Kuthe...


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