# Alpine PDX vs JL Audio



## doitor (Aug 16, 2007)

I'm considering a change in my amps but I'm undecided.
Options:

a)Alpine PDX 4.100 for tweeters and midrange, 4.100 for midbass, and 1.600 for sub.

or

b)Jl audio 300/4 for tweeters and midrange, 300/4 bridged for midbass and 500/1 for subs.

I can get both options for roughly the same $$$$$$.
So what do you think?


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## evan (Dec 2, 2006)

Alpine 
PDX-4.100: 7-9/16"L x 10-1/8"W x 2-7/16"H
PDX-1.600: 8-1/2"L x 10-3/16"W x 2-1/2"H

JL
300/4: 13.4"L x 9.25"W x 2.36"H
500/1: 13.4"L x 9.25"W x 2.36"H

The Alpines are smaller and make more power. That would be enough to make the decision for me.


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## SouthSyde (Dec 25, 2006)

i a/b both and prefered teh alpine.


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## Synergy324 (Nov 22, 2007)

evan said:


> Alpine
> PDX-4.100: 7-9/16"L x 10-1/8"W x 2-7/16"H
> PDX-1.600: 8-1/2"L x 10-3/16"W x 2-1/2"H
> 
> ...


I saw the PDX's at a shop tonight and was amazed at the power from such a small package. We all know the JL overproduces and is durable. Curious about the PDX's actually power and durability. 

Maybe its just me I can't see something half the size making the same power, when it comes to amps. I know technology has changed and materials have got more compact, power typically needs size! I have seen old Soundstream Class A amps 2x50 the size of that Alpine.


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## azngotskills (Feb 24, 2006)

a difference in amp topology: Class A/B vs Class D


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## Thumper26 (Sep 23, 2005)

yeah, the actual power outputs and amp efficiency has been proven over and over again. I say Alpine.


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## bobditts (Jul 19, 2006)

pdx amps are underrated so expect more actual power. They are smaller as well. If you have the space, I would say get the JLs. The PDX amps are still too new to know how durable they are.


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## crammit442 (Oct 9, 2007)

I've got Alpine. (1)PDX-1.600, (1)PDX-4.150, and (1)PDX-4.100. So far so good. On a side note, JL will soon have a competitive amp to the Alpine PDX series. Similar footprint and power. Don't know the release date.


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## kingofallreps (Nov 23, 2007)

Just like with any other decision you’re going to make in your audio system there is some give and take with these two amplifiers designs.
While the alpine is small and has very good power, the unregulated power supplies lacks in overall frequency response at varying voltage and frequency response. Good for size to power ratio.
The JL Audio amplifier is designed with a very tightly regulated power supply and will make rated power in any circumstance. The design of the amp is ensure rated power at any (almost) voltage and at any impedance. This is very important because as the speaker plays music through it, the impedance of the speaker changes.
Let’s say you amp is rated at 100 watts @ 4 ohm, and 50 watts at 8 ohm. When you your speaker play certain frequencies, it can produce upwards of 10 ohms! How much power does your amp produce at 10 ohm?! Is the unregulated power supply capable enough to produce rated power at 10 ohm?
This example is a bit extreme, but not far from the truth. The JL Audio amp is class A/B and has been proven since before Alpine was conceived to be the better sound topology. 
By the way, at CES, when the PDX amps were introduced, the display in the Alpine booth had a PDX amp on top of a silhouette of a JL Audio amplifier for comparison. When JL Audio introduced the R.I.P.S. power supply, Alpine actually said it was [hogwash] and would never sell or work. This year Alpine introduced their own version of the RIPS power supply.
So the JL Audio is a little bigger, same reason why Lexus is bigger than Toyota....


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## SouthSyde (Dec 25, 2006)

Just goto a nearby Tweeter and listen to both and let ur ears decide.


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## Puffhead (Aug 29, 2007)

I know the PDX are rated for power at 2 and 4 Ω loads. Anyone running them at a 1.5 Ω without incident? 

A buddy of mine offered to sell me his two 8w7 subs and I'd like to give them a shot and run them off of my PDX 1.600...but that means 1.5 Ω.

Never ran JL and I'm curious to play around with these little guys.

Opinions?

Thanks.


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## GlasSman (Nov 14, 2006)

bobditts said:


> pdx amps are underrated so expect more actual power. They are smaller as well. If you have the space, I would say get the JLs. The PDX amps are still too new to know how durable they are.



It's funny when you see what amps he uses in his system.

Talk about objectiveness.:blush:


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## CMR22 (Feb 10, 2007)

kingofallreps said:


> Just like with any other decision you’re going to make in your audio system there is some give and take with these two amplifiers designs.
> While the alpine is small and has very good power, the unregulated power supplies lacks in overall frequency response at varying voltage and frequency response. Good for size to power ratio.
> The JL Audio amplifier is designed with a very tightly regulated power supply and will make rated power in any circumstance. The design of the amp is ensure rated power at any (almost) voltage and at any impedance. This is very important because as the speaker plays music through it, the impedance of the speaker changes.
> Let’s say you amp is rated at 100 watts @ 4 ohm, and 50 watts at 8 ohm. When you your speaker play certain frequencies, it can produce upwards of 10 ohms! How much power does your amp produce at 10 ohm?! Is the unregulated power supply capable enough to produce rated power at 10 ohm?
> ...


I've been looking at both of these amps for a while now. Do you have a link to the testing you referenced in which JL was proven to have better sound topology? Also, was both the JL and Alpine amps tested at 10 ohms and their output compared? Thanks


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## Thumper26 (Sep 23, 2005)

on the topology, it's a/b vs. d. a/b has been proven for better sq.


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## t3sn4f2 (Jan 3, 2007)

Thumper26 said:


> on the topology, it's a/b vs. d. a/b has been proven for better sq.


Oh boy, someone's gonna give it to you for that one . Not me though


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## Thumper26 (Sep 23, 2005)

lol.

i didn't mean to type better, just sq. the technology that the pdx amps use seems to be pretty solid so far, but it's still young. In my opinion, a/b has an advantage for all the reasons that kingofallreps pointed out. But that's just my humble opinion...


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## avaxis (May 23, 2006)

Thumper26 said:


> on the topology, it's a/b vs. d. a/b has been proven for better sq.


proven is a strong word to use. . if its proven, i wonder why nobody won the RC $10,000 amp challenge.  

i'm running the PDX 4.150 and JL 500/1. both sounds good to me, clean with absolutely no hiss at all. both offer the dynamics and sufficient power on the tap.


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## CMR22 (Feb 10, 2007)

Thumper26 said:


> on the topology, it's a/b vs. d. a/b has been proven for better sq.


I understand its a/b vs. (full range) d but have these two particular amps been tested head to head and the JL came out the victor both objectively and subjectively? His post did not include "in my opinion" so I was assuming, perhaps incorrectly, that head to head testing had been completed versus "one amp is a/b and one amp is (full range) d so the a/b has to be better just because its a/b". 

I'm just curious.


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## ErinH (Feb 14, 2007)

I've got PDX's on front stage and JL on sub. 

If I could only go with one brand it would be the PDX's. Alot of power in a small package as everyone else says. The efficiency is also a HUGE aspect for me. I know the front stage amps for JL are a/b, while alpine's are all D, so that means that my front stage would be pushed with more efficiency. 

All of the above matters most to me because of my small car and small electrical. If I had more room, say an SUV, with a heftier electrical, I might try JL all around...but that's a slim might. 


FWIW, I'd give up my huge 1000/1 for a pdx 1.1000 if it wasn't so hard to sell my JL (another thing to keep in mind...resale). 

Just my $.02.


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## Thumper26 (Sep 23, 2005)

CMR22 said:


> I understand its a/b vs. (full range) d but have these two particular amps been tested head to head and the JL came out the victor both objectively and subjectively? His post did not include "in my opinion" so I was assuming, perhaps incorrectly, that head to head testing had been completed versus "one amp is a/b and one amp is (full range) d so the a/b has to be better just because its a/b".
> 
> I'm just curious.


yeah i should have put 'in my opinion'. that's what happens when you post at work in between tasks. 

a/b has been around longer, and i've never got to compare the pdx vs. the jl in the same install with teh same speakers to see if i could tell a difference, but as it stands, i'll lean towards a/b for better sq for now.

things are always changing, and the pdx amps have a great track record so far. i would have no problem running pdx amps in my system, almost did in fact, but it is still a somewhat new technology, and i think it will take a while before it gets really settled in.


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## michaelsil1 (May 24, 2007)

Thumper26 said:


> yeah i should have put 'in my opinion'. that's what happens when you post at work in between tasks.
> 
> a/b has been around longer, and i've never got to compare the pdx vs. the jl in the same install with teh same speakers to see if i could tell a difference, but as it stands, i'll lean towards a/b for better sq for now.
> 
> things are always changing, and the pdx amps have a great track record so far. i would have no problem running pdx amps in my system, almost did in fact, but it is still a somewhat new technology, and i think it will take a while before it gets really settled in.


I was running the PDX 4x150 on my two way front stage I wasn't that thrilled with the way the tweeters sounded so I went with the JL Slash 300/2v2 on the tweets and bridged the PDX for the mids the tweeters sound better with the JL.


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## bobditts (Jul 19, 2006)

Thumper26 said:


> on the topology, it's a/b vs. d. a/b has been proven for better sq.


where is this said proof? There are plenty of SQ competitors winning with full range class D amps.


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## doitor (Aug 16, 2007)

Do you guys think that the amplifier brand has something to do with the winning or not of a competition?
By example if a judge knows that you are using a "bad" brand of amps will in influence his decision vs a "good and expensive" amp.
I know it shouldn't, but does it?


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## calponte (May 25, 2007)

I think a better point about bobditt's post is that if the SQ of the full range class D amps were so inferior...would they actually be able to pull off wins?


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## bobditts (Jul 19, 2006)

doitor said:


> Do you guys think that the amplifier brand has something to do with the winning or not of a competition?


no one said anything about brands. We are talking about class a/b versus full range class d


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## doitor (Aug 16, 2007)

bobditts said:


> no one said anything about brands. We are talking about class a/b versus full range class d


It seems that I was hijacking my post. LOL.
I'll post another thread.


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## bobditts (Jul 19, 2006)

doitor said:


> It seems that I was hijacking my post. LOL.
> I'll post another thread.


I thought that was in response to my post. Sorry.  

Judges are not supposed to take brands into consideration when judging competitions. Does that mean it never happens? only the judge will ever really know.


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## doitor (Aug 16, 2007)

bobditts said:


> I thought that was in response to my post. Sorry.
> 
> Judges are not supposed to take brands into consideration when judging competitions. Does that mean it never happens? only the judge will ever really know.


It wasn't in response to your post. LOL.
Just posted another thread.


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## wdemetrius1 (Aug 16, 2007)

To settle the matter why don't someone use both amps in the same car with the same speakers and report back. I'm sure that we could find someone to loan their amps for the review. Just a thought.


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## oneiztoomany (Oct 1, 2007)

pleased with my PDX amps...hard to say whether i would be happier with JL amps without a direct swap. 

in my case though the size of the PDX make them more than ideal. i was able to mount the two PDX amps i have under each one of my seats. not many 1000 watt amps will fit under the driver's seat of a acura tsx!


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## Puffhead (Aug 29, 2007)

Puffhead said:


> I know the PDX are rated for power at 2 and 4 Ω loads. Anyone running them at a 1.5 Ω without incident?
> 
> A buddy of mine offered to sell me his two 8w7 subs and I'd like to give them a shot and run them off of my PDX 1.600...but that means 1.5 Ω.
> 
> ...


anyone?


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## OgreDave (Jul 13, 2005)

Just run one w7 for a 3ohm load? IMO not worth the risk.


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## ErinH (Feb 14, 2007)

Puffhead said:


> anyone?


Just make a call to Alpine. I don't think any of us here can help you with that.


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## OgreDave (Jul 13, 2005)

Alpine's gonna tell him it's not supported ..


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## Puffhead (Aug 29, 2007)

Ok guys thanks. I think I'll play it safe. For now


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## bass_lover1 (Dec 10, 2005)

Synergy324 said:


> I saw the PDX's at a shop tonight and was amazed at the power from such a small package. We all know the JL overproduces and is durable. Curious about the PDX's actually power and durability.
> 
> Maybe its just me I can't see something half the size making the same power, when it comes to amps. I know technology has changed and materials have got more compact, power typically needs size! I have seen old Soundstream Class A amps 2x50 the size of that Alpine.


I didn't read the rest of the thread, however, if this is your philosophy, modern computers would be the size of football stadiums, and your 200 gig hard drive would probably weigh well over a ton, and occupy the space of say a moderately sized guest bedroom.


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## OgreDave (Jul 13, 2005)

They make the power .. see review section. It's the class D technology that makes it work. B&O 'ICE' or whatever.


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## matdotcom2000 (Aug 16, 2005)

Ok this is what I am going to do I have a friend with some pdx amps and I happen to own some jl slash amps. We will do a head to head comparison and also try to find out the electrical foot print of the a/b class to the d class and I will get back to you guys.....


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## ErinH (Feb 14, 2007)

matdotcom2000 said:


> Ok this is what I am going to do I have a friend with some pdx amps and I happen to own some jl slash amps. We will do a head to head comparison and also try to find out the electrical foot print of the a/b class to the d class and I will get back to you guys.....


Get a 3rd friend there who can swap wires for you guys in random order while one is listening. The 2nd guy can stand back there and watch.


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## t3sn4f2 (Jan 3, 2007)

bikinpunk said:


> Get a 3rd friend there who can swap wires for you guys in random order while one is listening. The 2nd guy can stand back there and watch.


Still won't work. Subconscious involuntary communication threw body language, facial expressions and eye contact will contaminate the results  .


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## ErinH (Feb 14, 2007)

t3sn4f2 said:


> Still won't work. Subconscious involuntary communication threw body language, facial expressions and eye contact will contaminate the results  .


lol. at first I took that reply as literal and was like "how can he tell if he's starting forward and the guy is in the back with the trunk lid covering his entire body". :blush:


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## t3sn4f2 (Jan 3, 2007)

bikinpunk said:


> lol. at first I took that reply as literal and was like "how can he tell if he's starting forward and the guy is in the back with the trunk lid covering his entire body". :blush:


lol, yeah its a little too controlled for this type of test. Besides I doubt that anyone can even begin to say they can tell a difference between the two, much less pick one as sounding better when you take into consideration the time it takes to turn the system off, swap RCAs, wait for the system to power up and start playing again. It will be an interesting read but I don't think I'll put too much stock in it.


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## oneiztoomany (Oct 1, 2007)

t3sn4f2 said:


> Still won't work. Subconscious involuntary communication threw body language, facial expressions and eye contact will contaminate the results  .


make sure ambient temperature is the same also


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## calponte (May 25, 2007)

..and that the AC output voltage is too


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## t3sn4f2 (Jan 3, 2007)

oneiztoomany said:


> make sure ambient temperature is the same also


uh and how does that influence the choice the person makes? It can affect the test but not the person......


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## wdemetrius1 (Aug 16, 2007)

matdotcom2000 said:


> Ok this is what I am going to do I have a friend with some pdx amps and I happen to own some jl slash amps. We will do a head to head comparison and also try to find out the electrical foot print of the a/b class to the d class and I will get back to you guys.....



Now we are starting to cook with gas. I look forward to the results.


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## ErinH (Feb 14, 2007)

t3sn4f2 said:


> when you take into consideration the time it takes to turn the system off, swap RCAs, wait for the system to power up and start playing again.


Nah, just hot swap 'em.


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## wdemetrius1 (Aug 16, 2007)

Will the test ever happen?


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## OldOneEye (Jun 16, 2005)

kingofallreps said:


> The JL Audio amplifier is designed with a very tightly regulated power supply and will make rated power in any circumstance. The design of the amp is ensure rated power at any (almost) voltage and at any impedance. This is very important because as the speaker plays music through it, the impedance of the speaker changes.
> Let’s say you amp is rated at 100 watts @ 4 ohm, and 50 watts at 8 ohm. When you your speaker play certain frequencies, it can produce upwards of 10 ohms! How much power does your amp produce at 10 ohm?! Is the unregulated power supply capable enough to produce rated power at 10 ohm?


Anthony,
Not sure it works that way. Pretty sure that the RIPS checks the impedence when it powers up and then adjust accordingly once (until you cycle it off and back on again). So if you hook in a nominally 4 ohm speaker, it doesn't put out more power if that thing hits 8 ohms at a certain set of frequencies. Sort of like the jumpers I think Soundstream and Linear Power amps used to have, but this is done automatically at when you cycle it on.

And for the the 300/4, the power supply only has one setting. So it can only make one adjustment. So if you wire 4 ohms to the front and 8 ohms to the rear, the rears will not get full power.

Juan


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## cvjoint (Mar 10, 2006)

And it won't do the same power at 10ohm anyways. It's only regulated so far. I've used the 450/4 JL and wasn't too impressed. It was a bit dull sounding and didn't image too well.


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## matdotcom2000 (Aug 16, 2005)

cvjoint said:


> And it won't do the same power at 10ohm anyways. It's only regulated so far. I've used the 450/4 JL and wasn't too impressed. It was a bit dull sounding and didn't image too well.


What additional equipment did you use with it??? I am just curious


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## cvjoint (Mar 10, 2006)

I was using the Seas Lotus set, RT25A and 165w the first version.


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## andthelam (Aug 9, 2006)

OldOneEye said:


> Anthony,
> Not sure it works that way. Pretty sure that the RIPS checks the impedence when it powers up and then adjust accordingly once (until you cycle it off and back on again). So if you hook in a nominally 4 ohm speaker, it doesn't put out more power if that thing hits 8 ohms at a certain set of frequencies. Sort of like the jumpers I think Soundstream and Linear Power amps used to have, but this is done automatically at when you cycle it on.
> 
> And for the the 300/4, the power supply only has one setting. So it can only make one adjustment. So if you wire 4 ohms to the front and 8 ohms to the rear, the rears will not get full power.
> ...


I was told by a JL tech. that each pair of channels sees its own impedance and adjusts the rail voltage accordingly independent of one another. He may have lied to me (or he doesnt know any better). Anyways, where did you read, hear or understand this particular make of amp that this was the case?


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## iyamwutiam (Nov 20, 2006)

Juan - didn't you use to run a ton of the xtant 1.1is or something? What do you think - I guess it's positive of the D class full range. I have had quite a few people tell me they don't like PDXs- mainly installers.


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## quality_sound (Dec 25, 2005)

andthelam said:


> I was told by a JL tech. that each pair of channels sees its own impedance and adjusts the rail voltage accordingly independent of one another. He may have lied to me (or he doesnt know any better). Anyways, where did you read, hear or understand this particular make of amp that this was the case?



Besides the manual?  Seriously, when I read the manual for the 300/4 I used to have and that was something I remembered from it. Also, over 8 ohms it will make less power than between 2 and 8 ohms.


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## matdotcom2000 (Aug 16, 2005)

quality_sound said:


> Besides the manual?  Seriously, when I read the manual for the 300/4 I used to have and that was something I remembered from it. Also, over 8 ohms it will make less power than between 2 and 8 ohms.


You are right that it will make less power at 8 ohm than at two but the amp is UNDERRATED meaning that it will still make its rated power when bridged to two channels at 8 ohms and an oldie but goodie review here http://www.carsound.com/review_archive/amps/jl_3004.html


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## quality_sound (Dec 25, 2005)

matdotcom2000 said:


> You are right that it will make less power at 8 ohm than at two but the amp is UNDERRATED meaning that it will still make its rated power when bridged to two channels at 8 ohms and an oldie but goodie review here http://www.carsound.com/review_archive/amps/jl_3004.html


Your point? Never said it wouldn't make rated power at 8 ohms bridged. I said it wouldn't make rated power OVER 8 ohms. Part of the design.


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## chad (Jun 30, 2005)

andthelam said:


> I was told by a JL tech. that each pair of channels sees its own impedance and adjusts the rail voltage accordingly independent of one another. He may have lied to me (or he doesnt know any better). Anyways, where did you read, hear or understand this particular make of amp that this was the case?


JL told me it shifted the whole amp, so if I ran 2 channels 4 ohms bridged it sees 2 ohms and adjusts the whole PS accordingly thus giving less power to a pair of 4 ohm drivers on the other 2 channels. Rail voltage for an 8 onm pair and 4 ohm pair would be the same though.

Honestly... I don't think JL even knows


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## OldOneEye (Jun 16, 2005)

chad said:


> JL told me it shifted the whole amp, so if I ran 2 channels 4 ohms bridged it sees 2 ohms and adjusts the whole PS accordingly thus giving less power to a pair of 4 ohm drivers on the other 2 channels. Rail voltage for an 8 onm pair and 4 ohm pair would be the same though.
> 
> Honestly... I don't think JL even knows


What you are describing is in the owners manual. Nothing newsworthy here. The larger 4 channel has two power supplies so they can adjust independently.

Juan


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## chad (Jun 30, 2005)

OldOneEye said:


> What you are describing is in the owners manual. Nothing newsworthy here. The larger 4 channel has two power supplies so they can adjust independently.
> 
> Juan


That's very cool, my 500/5 is the same way. I thought it was rather odd and I remember saying to the guy (when I finally got someone who knew) "Are you SURE it works this way?" it just seemed kinda limiting and rules out a 300/4 for sub/FR duty


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## OldOneEye (Jun 16, 2005)

chad said:


> That's very cool, my 500/5 is the same way. I thought it was rather odd and I remember saying to the guy (when I finally got someone who knew) "Are you SURE it works this way?" it just seemed kinda limiting and rules out a 300/4 for sub/FR duty


Doesn't rule FR/Sub duty, just choices in speakers.

Juan


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## chad (Jun 30, 2005)

OldOneEye said:


> Doesn't rule FR/Sub duty, just choices in speakers.
> 
> Juan


Yeah, but unfortunately the drivers were already picked out


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