# Alpine Pdx vs mrx



## ccapil (Jun 1, 2013)

Looking at a decent mono amp for a budget around $400 or less, and need about 600 watts rms into 2 ohms. Looking at the alpine pdx series and the mrx m55. My question is how do the alpine mrx m55 and pdx m6 compare performance wise cost etc? I know pdx is alpines top of the line but if I can save 200$ would the mrx-m55 be a good choice?

Or any other amp suggetsions?

Thanks


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## RNBRAD (Oct 30, 2012)

Ive got two mrx-m55's, mrx-m100 as well. I was not convinced of the need to spend the extra dough on the pdx. I say go the mrx. These amps have some balls too, eventhough they are class D, they pull some juice.


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## ZAKOH (Nov 26, 2010)

I heard that Alpine MRX amps are built internally as a bridged 2-channel amplifier. This means that when you run 2ohm subwoofer, it's like running individual channels at 1ohm. They have good power output, but I don't really like this idea. This may be also the reason why the amp is not 1ohm stable.


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## RNBRAD (Oct 30, 2012)

ZAKOH said:


> I heard that Alpine MRX amps are built internally as a bridged 2-channel amplifier. This means that when you run 2ohm subwoofer, it's like running individual channels at 1ohm. They have good power output, but I don't really like this idea. This may be also the reason why the amp is not 1ohm stable.


Mrx is 1 ohm stable. Ran it 1 ohm for quite some time. It does however drop power output at 1ohm


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## 68962 (Aug 19, 2013)

You should look at Phoenix Gold's R series amps. Much more of an amp than anything Alpine has to offer.


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## 68962 (Aug 19, 2013)

RNBRAD said:


> Mrx is 1 ohm stable. Ran it 1 ohm for quite some time. It does however drop power output at 1ohm


Power output is reduced at 1ohm?? You know an ohm is a measurement of electrical resistance so the lower the ohms the more output? Maybe I misunderstood you... 

Anyway Alpine amps are overpriced. 
MRX is $250 for 500 worms...
Q1-750 is $210 for 750 worms...
Alpine = $0.50 per worm
Soundqubed = $0.28 per worm

Plus I highly doubt that Alpine even puts clean power out @ 500wrms. I know that the Q1-750 does.

Point is that you can find much better quality for much better price.


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## ccapil (Jun 1, 2013)

I've heard good reviews on the alpine mrx m55. It puts out 581 watts rms at 2 ohm at 14.8 volts. What other amps of good quality do u all recommend for $400 or less?


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## 68962 (Aug 19, 2013)

ccapil said:


> I've heard good reviews on the alpine mrx m55. It puts out 581 watts rms at 2 ohm at 14.8 volts. What other amps of good quality do u all recommend for $400 or less?


For $400 you can get an amp that does 2200 watts rms man... Forget about Alpine. 

Crap China Boards:
Alpine
Rockford Fosgate
Pioneer
Sony
Kenwood

Decent China/Korean Boards:
Crescendo
Soundqubed
Phoenix Gold
American Bass
Sundown

Do some research with the thought in mind that there are better options than these giant brand names for less money.

So do some research and come back here, ask questions about the amps that catch your eye, and I will be more than happy to help you man.

Edit: let me clarify that I am regarding AMPS and not subs. I actually like Alpine's subs particularly the Type R and also the Type X. Again though spend about the same $$$ and you can get a better product.


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## RNBRAD (Oct 30, 2012)

OneSpiritBrain said:


> Power output is reduced at 1ohm?? You know an ohm is a measurement of electrical resistance so the lower the ohms the more output? Maybe I misunderstood you...
> 
> Anyway Alpine amps are overpriced.
> MRX is $250 for 500 worms...
> ...


Nope you didnt misunderstand me. Alpine deemed it necessary to reduce output of the mrx-m55 at 1ohm instead of making the amp unstable. Nice option when you have a 1 ohm load. These amps can be purchased for around 200. They are CEA compliant so you know exactly what your getting.


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## ZAKOH (Nov 26, 2010)

RNBRAD said:


> Mrx is 1 ohm stable. Ran it 1 ohm for quite some time. It does however drop power output at 1ohm


The fact that power drops at 1ohm seems to imply that it's not really that "stable" in this mode operation. After all, the two channels internally now have to see 0.5ohm impedance. Anyways, my point is that even if you run it at 2ohms, this will be like running other amps at 1ohm. A bigger tax on the electrical system and it will run hotter. There are plenty of traditional mono amplifiers that will do 1000 watts at 2ohm without breaking a sweat.


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## RNBRAD (Oct 30, 2012)

ZAKOH said:


> The fact that power drops at 1ohm seems to imply that it's not really that "stable" in this mode operation. After all, the two channels internally now have to see 0.5ohm impedance. Anyways, my point is that even if you run it at 2ohms, this will be like running other amps at 1ohm. A bigger tax on the electrical system and it will run hotter. There are plenty of traditional mono amplifiers that will do 1000 watts at 2ohm without breaking a sweat.


These things don't break a sweat, not even close. Probably the coolest operating amps I have ever used. I have 3 running at 2 ohms, I can't hardly get them to get warm to the touch. The mrx-m110 can be picked up for around 250. Not bad for a true 1100 watt amp, puts out close to 1200 on the certificate.


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## ccapil (Jun 1, 2013)

Lol Rockford and alpine aren't crap and was just after opinions if its worth the extra money and get the pdx? Probably going to get the mrx m55. Or unless something else good comes along.


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## Serieus (May 27, 2011)

OneSpiritBrain said:


> Power output is reduced at 1ohm?? You know an ohm is a measurement of electrical resistance so the lower the ohms the more output? Maybe I misunderstood you...
> 
> Anyway Alpine amps are overpriced.
> MRX is $250 for 500 worms...
> ...


it also means more current (p=iv, which turns into p=i^2*r using ohms law) which is harder on an amp. it drops power at one ohm most likely because of the same thermal protection that the pdx series has which scales output in incredibly small increments to maintain stability.

additionally, alpine amps are among the best mainstream amps available and certainly *do* provide MORE clean power than they're rated for. they also happen to run quite cool and have great form factors (small). lastly, there's more to amps than just watts, although ill admit that i couldn't really care less on a sub amp. 

i would certainly pay the extra for the alpine. they're built well and are solid performers, and i like their cs.


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## ZAKOH (Nov 26, 2010)

ccapil said:


> I've heard good reviews on the alpine mrx m55. It puts out 581 watts rms at 2 ohm at 14.8 volts. What other amps of good quality do u all recommend for $400 or less?


If you get PPI Phantom or Soundstream Tarantula amplifiers, those will be solid performers. They share the same board. I had P900.4 and P1000.1. Both are solid performers. P1000.1 is supposedly capable of 1000watt output at 2ohm, but was underrated unlike its twin. If you need just 500-600watts, get the 2-channel amp and bridge it. Those are tiny and very cheap.


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## 68962 (Aug 19, 2013)

If I was gonna buy a china crap amp I'd go with the VVME INNO-D1500 for $95 or the audiopipe APSM-1500 for $150.

Anyway yeah, buy the alpine man...


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## Kriszilla (Jul 1, 2013)

OneSpiritBrain said:


> If I was gonna buy a china crap amp I'd go with the VVME INNO-D1500 for $95 or the audiopipe APSM-1500 for $150.
> 
> Anyway yeah, buy the alpine man...


Have you actually opened up a PDX and taken a solid look at the power regulation on the board as well as its design layout? It's a pretty phenomenal work of art. 

Dropping power at 1 Ohm is for stability. On the PDX series, the thermal protection is stellar. Instead of cutting out completely, the amp can scale back the power a bit until it reaches nominal thermal safety limits again. 

There are advantages to having build houses overseas (Malaysia, Korea, China, Taiwan, etc...). They have the tooling, the fabs, and the mass-production experience already in place

What it comes down to is design and Quality Control. You can have a crappy design built all day long and do ****ty QC /QA to it and then sell that crappy product.

Or, like Alpine, JL, Rockford, Pioneer, Intel, AMD, nVidia, Seagate, Samsung yada yada yada, you can put the R&D into engineering a fantastic design, then follow it up with quality parts + build process + solid QC / QA and turn out an item much cheaper overseas.

Methinks you have no idea of which you speak.

Source: Me. An ex-Engineer for Seagate Technology who has actually visited overseas fabrication centers. BTW, factoid for the day, at one time in the 90's, Seagate's clean room in Malaysia was the largest private clean room in the world at two football fields in size, second only to NASA's at Goddard.


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## RNBRAD (Oct 30, 2012)

Me thinks the same thing. I mean Alpine can stand on its own against the best the market has to offer. These budget brands have a long way to go before they can be compared to Alpine. It was immediately apparent when someone questions Alpine level of clean power output, yet recommend something that literally has 10x the distortion rating for power ratings and is not cea complaint to back up its horrible specs. So just how overpriced is an Alpine?


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## Serieus (May 27, 2011)

Kriszilla said:


> Source: Me. An ex-Engineer for Seagate Technology who has actually visited overseas fabrication centers. BTW, factoid for the day, at one time in the 90's, Seagate's clean room in Malaysia was the largest private clean room in the world at two football fields in size, second only to NASA's at Goddard.


clean rooms are fun times, we made antennas on silicon wafers in my intro to engineering class last year. looked like astronauts


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## therapture (Jan 31, 2013)

SORRY, you don't know what you are talking about...




OneSpiritBrain said:


> Power output is reduced at 1ohm?? You know an ohm is a measurement of electrical resistance so the lower the ohms the more output? Maybe I misunderstood you...
> 
> Anyway Alpine amps are overpriced.
> MRX is $250 for 500 worms...
> ...


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## therapture (Jan 31, 2013)

OneSpiritBrain said:


> You should look at Phoenix Gold's R series amps. Much more of an amp than anything Alpine has to offer.


The ignorance is strong in this one...


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## Kriszilla (Jul 1, 2013)

Serieus said:


> clean rooms are fun times, we made antennas on silicon wafers in my intro to engineering class last year. looked like astronauts


Nice! I've always wanted to see a real wafer-fab. 

I got to do the bunny-suit tour of the sections responsible for the platters on the 10K RPM Cheetah SCSI drives and the Barracuda-series final assembly line.

I don't know that I'd want to work in one all day, but it was a great experience.


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## Serieus (May 27, 2011)

Kriszilla said:


> Nice! I've always wanted to see a real wafer-fab.
> 
> I got to do the bunny-suit tour of the sections responsible for the platters on the 10K RPM Cheetah SCSI drives and the Barracuda-series final assembly line.
> 
> I don't know that I'd want to work in one all day, but it was a great experience.


it was a good time. i agree on the whole not wanting to work in one all day but it's something different, pretty cool to go check it out for sure. i'd like to go to one of the bigger ones, like intel, tsmc, global foundries, etc -- not sure how the hard drive ones compare to the bigger ones now but i'm sure they're similar given how delicate the platters are. i'm sure it's quite a bit different from what we have


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## ccapil (Jun 1, 2013)

Way off topic lol so problay going with the mrx m55 or a Rockford foagate punch if I can find one 500 watts rms for my budget


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## therapture (Jan 31, 2013)

I believe it has been conclusively proven that onespiritbrain:

1. knows nothing about alpine amps
2. understands relatively little about amplifiers and ohm loading
3. is talking out of his ass

Alpine is a great choice, MRX or PDX. I went the V9 because I wanted a tiny package with 5 channels of amplification.


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## ChrisB (Jul 3, 2008)

RNBRAD said:


> Nope you didnt misunderstand me. Alpine deemed it necessary to reduce output of the mrx-m55 at 1ohm instead of making the amp unstable. Nice option when you have a 1 ohm load. These amps can be purchased for around 200. *They are CEA compliant so you know exactly what your getting.*


Care to tell everyone what nominal impedance is CEA compliant? 

4 ohms, which means anything less than 4 can be an "if struck by lighting" pipe dream, leaving the consumer NOT knowing what they are getting. The Kenwood 9104d, for example, was CEA compliant and many wouldn't even run at 1 ohm or make close to rated power at 2 ohms.

I'm not saying this to rip on you, but I am tossing it out there as a warning for anyone relying on the CEA certification. It's only good for 14.4 volts at 4 ohms with less than 1% distortion! Anything other than that is outside the scope of CEA certification.


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## 68962 (Aug 19, 2013)

Yall should get some audiobahn subs for those alpine amps. They should pair nicely 

CEA = Clipping Every Amp


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## RNBRAD (Oct 30, 2012)

ChrisB said:


> Care to tell everyone what nominal impedance is CEA compliant?
> 
> 4 ohms, which means anything less than 4 can be an "if struck by lighting" pipe dream, leaving the consumer NOT knowing what they are getting. The Kenwood 9104d, for example, was CEA compliant and many wouldn't even run at 1 ohm or make close to rated power at 2 ohms.
> 
> I'm not saying this to rip on you, but I am tossing it out there as a warning for anyone relying on the CEA certification. It's only good for 14.4 volts at 4 ohms with less than 1% distortion! Anything other than that is outside the scope of CEA certification.


Yes you shouldn't assume a CEA certification will guarantee an amps performance beyond the CEA test parameters. However, Alpine among many other CEA compliant amps don't need CEA compliance certification for any of their ratings at any ohm. If Alpine says their amp will do 587 watts at 2ohms, and 400 at 1 ohm, I don't need a certification to convince me of it. An audiopipe or a soundqubed or other cheap unknown brand, going to take a CEA compliance for me even to consider it. It helps the consumers not in the know to wade through all the BS.


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## 68962 (Aug 19, 2013)

therapture said:


> I believe it has been conclusively proven that onespiritbrain:
> 
> 1. knows nothing about alpine amps
> 2. understands relatively little about amplifiers and ohm loading
> ...


1. Yes you are right! Buy two Alpines!
2. Right again!! Wow! Don't forget your SuPeR pHaT bASs box aka Probox
3. Better get some capacitors too. Not super capacitors though, you would loose your hand/fingers I'm sure...


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## 68962 (Aug 19, 2013)

RNBRAD said:


> Yes you shouldn't assume a CEA certification will guarantee an amps performance beyond the CEA test parameters. However, Alpine among many other CEA compliant amps don't need CEA compliance certification for any of their ratings at any ohm. If Alpine says their amp will do 587 watts at 2ohms, and 400 at 1 ohm, I don't need a certification to convince me of it. An audiopipe or a soundqubed or other cheap unknown brand, going to take a CEA compliance for me even to consider it. It helps the consumers not in the know to wade through all the BS.


If its CEA compliant then it means the company is crooked and needs a super special seal so you can believe what they say.


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## chevbowtie22 (Nov 23, 2008)

OneSpiritBrain said:


> If its CEA compliant then it means the company is crooked and needs a super special seal so you can believe what they say.


Go home troll. You're not needed here. I hear ca.com is nice though . . .


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## ccapil (Jun 1, 2013)

Yes there are good amplifiers that don't have CEA-2006 compliant power ratings, but usually those manufacturers will publish their own guidelines for supply voltage, distortion and frequency range, CEA ensures a amp says want it is meant to do power wise before its boxed up, BUT can and will change in reality as there are many in- efficiencies when running an amp in a car. Voltage for one example


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## 68962 (Aug 19, 2013)

chevbowtie22 said:


> Go home troll. You're not needed here. I hear ca.com is nice though . . .


I know right

Edit: no tapatalk support...


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## ZAKOH (Nov 26, 2010)

Kriszilla said:


> Dropping power at 1 Ohm is for stability. On the PDX series, the thermal protection is stellar. Instead of cutting out completely, the amp can scale back the power a bit until it reaches nominal thermal safety limits again.



Actually, I think having the amplifier drop the output silently is a BAD decision. I can only imagine this: on a hot summer day I start blasting some music really loud. Suddenly it doesn't sound right. At this point I start wondering: is it my ears playing games with my mind, or was the recording made this way, or is something else at play? At least if the amplifier simply cut off completely, then I would know immediately that either my installation is not adequate or the amplifier is not adequate for my install.


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## ccapil (Jun 1, 2013)

Mrx m55 isn't 1 ohm stable (not recommended) so that's y the output drops at 1 ohm? In theory it shouldn't


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## therapture (Jan 31, 2013)

In south texas summers, that scaling back of power is a good thing IMO. Short of having my amp cooled by AC or mounted on the roof, there's not a lot I can do for it in the trunk hahaha.

And since the amp never maxes out temp wise and shuts off, that helps with longevity.


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## therapture (Jan 31, 2013)

OneSpiritBrain said:


> 1. Yes you are right! Buy two Alpines!
> 2. Right again!! Wow! Don't forget your SuPeR pHaT bASs box aka Probox
> 3. Better get some capacitors too. Not super capacitors though, you would loose your hand/fingers I'm sure...




You are definitely an idiot. Typical response of an ignorant asshat, when shown to be as such.


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## Serieus (May 27, 2011)

ZAKOH said:


> Actually, I think having the amplifier drop the output silently is a BAD decision. I can only imagine this: on a hot summer day I start blasting some music really loud. Suddenly it doesn't sound right. At this point I start wondering: is it my ears playing games with my mind, or was the recording made this way, or is something else at play? At least if the amplifier simply cut off completely, then I would know immediately that either my installation is not adequate or the amplifier is not adequate for my install.


i think i read somewhere that the pdx drops outputs in something like 0.1 dB increments, you'd probably never notice it was doing anything. my amp is sandwiched between carpet in a car with no ac and even on 100+ days after a couple of hours of loud play I've never noticed anything


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## therapture (Jan 31, 2013)

Serieus said:


> i think i read somewhere that the pdx drops outputs in something like 0.1 dB increments, you'd probably never notice it was doing anything. my amp is sandwiched between carpet in a car with no ac and even on 100+ days after a couple of hours of loud play I've never noticed anything


Mine is in the trunk, and after sitting in 95f temps all day, the amp is ALREADY hot when I listen to it, and I have never noticed any difference even after 2 hour long road trips with fairly loud volume. It's not like the amp is always delivering maximum wattage anyways.

If your "loud" average is say, 300w output, and the max output is say, 500w....does it matter much if the amp scales back the max power output to say, 425w? Probably not much...


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## austin4heatwave (Feb 22, 2009)

OneSpiritBrain said:


> I know right
> 
> Edit: no tapatalk support...


onespiritbrain stop trolling.....its not welcome here......be helpful or be gone.....


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## Serieus (May 27, 2011)

therapture said:


> Mine is in the trunk, and after sitting in 95f temps all day, the amp is ALREADY hot when I listen to it, and I have never noticed any difference even after 2 hour long road trips with fairly loud volume. It's not like the amp is always delivering maximum wattage anyways.
> 
> If your "loud" average is say, 300w output, and the max output is say, 500w....does it matter much if the amp scales back the max power output to say, 425w? Probably not much...


agreed, and i had mine running bridged to my sub too. I'm not saying it doesn't or didn't get hot but I've never noticed the thermal protection. everyone has their opinion but the thermal protection is what drove me to the pdx amps, because my old mtx from years back kept shutting down on me. to each their own 

I think the protection for the mrx is a bit less sophisticated but overall i would imagine its very similar and very good


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## 68962 (Aug 19, 2013)

austin4heatwave said:


> onespiritbrain stop trolling.....its not welcome here......be helpful or be gone.....


my name is michael.

did you even read the thread??? i WAS being helpful... The guy asked for suggestions on amps and I gave some to him. there was continued talk of Alpine amps so I expanded on why Alpine is crap compared to the other amps I mentioned. 

these guys are obviously uninformed so i attempted to inform them. they rejected good sense and showed ill content towards me so i returned the gesture. yes i may have gone overboard just a bit.. for that i apologize but the true intent of my comments were to show them there are WAAAYY better choices than Alpine and refusing to even indulge the idea is just plain IGNORANT. the very definition...

kthanx


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## Kriszilla (Jul 1, 2013)

You recommended an amp that was (a) discontinued, and (b) wasn't 600 RMS @ 2 ohm.


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## austin4heatwave (Feb 22, 2009)

OneSpiritBrain said:


> my name is michael.
> 
> did you even read the thread??? i WAS being helpful... The guy asked for suggestions on amps and I gave some to him. there was continued talk of Alpine amps so I expanded on why Alpine is crap compared to the other amps I mentioned.
> 
> ...


yeah I read the whole thread and I stand by my comment to you


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## austin4heatwave (Feb 22, 2009)

ccapil said:


> Looking at a decent mono amp for a budget around $400 or less, and need about 600 watts rms into 2 ohms. Looking at the alpine pdx series and the mrx m55. My question is how do the alpine mrx m55 and pdx m6 compare performance wise cost etc? I know pdx is alpines top of the line but if I can save 200$ would the mrx-m55 be a good choice?
> 
> Or any other amp suggetsions?
> 
> Thanks


im not sure of prices of gear in new Zealand but if you can wait about a week I have a ss ref amp coming to me give me a chance to give it a look and I would say get the ref 1.1000 from onlinecarstereo its way under your budget and will provide plenty of power Soundstream REF1.1000 Mono Subwoofer Amplifiers at Onlinecarstereo.com

there are other options out there besides alpine but it really depends on what brands you have available to you. im not sure what shipping is like to new Zealand. I have used 3 of alpines current amp offerings and all 3 performed well


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## 68962 (Aug 19, 2013)

Kriszilla said:


> You recommended an amp that was (a) discontinued, and (b) wasn't 600 RMS @ 2 ohm.


which amp was discontinued? Q1-1200D BAM [email protected]


austin4heatwave said:


> yeah I read the whole thread and I stand by my comment to you


well thats your prerogative


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## ccapil (Jun 1, 2013)

I can get the mrx m55 here in nz for $280 compared to the pdx which is $580. I'd prefer to buy here in nz but could possibly get from the states ebay, sonic etc. I've had good luck and performance out of alpine so far and have heard good things on the mrx line, really high dampening factor, much broader range of freq response, similar pdx technology inside...
I'm going to get the mrx m55 since its relaravliy cheap and I can't find anything else of good quality $400<


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## therapture (Jan 31, 2013)

OneSpiritBrain said:


> my name is michael.
> 
> did you even read the thread??? i WAS being helpful... The guy asked for suggestions on amps and I gave some to him. there was continued talk of Alpine amps so I expanded on why Alpine is crap compared to the other amps I mentioned.


No...you slammed Alpine, which is NOT a crap amp, and suggested an amp that while it may be fine, is not exactly better than the equivalent Alpine offering, for many reasons, none of which you chose to list or express.

You sound like a fanboy, and you expressed ignorance and lack of knowledge.


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## 68962 (Aug 19, 2013)

therapture said:


> No...you slammed Alpine, which is NOT a crap amp, and suggested an amp that while it may be fine, is not exactly better than the equivalent Alpine offering, for many reasons, none of which you chose to list or express.
> 
> You sound like a fanboy, and you expressed ignorance and lack of knowledge.


I slammed Alpine to catch the OPs attention in hopes to make him aware that for the same amount of cash you can get a beefier amp that uses quality parts. 

I've used Alpine amps and I'm telling you from experience that there are better products for less money. 

I had a MRD-M1000 with all the bells and whistles. I paid $500 for that thing and set the gains with my fluke true rms ddm. I ran a db drive platinum 12 and that stupid amp charred the VC and the sub failed. That's 750wrms out of a 1000wrns amp and it couldn't even do that... and Alpine was hailing that amp as if it was the holy grail. 

Next amp was an AQ-2200d and not only did it do rated COMPLETELY CLEAN but it was less stressful on my electrical than the MRD-M1000. 

Look I'm not saying that Alpine is equal to Sony Xplod and the likes but you are paying big time for a processor that protects you from being an idiot. You have to be aware of your electrical status when taxing it with an amplifier or two.

Anyway the Phoenix Gold R series is considered quasi SQ and was designed to sound good and still be powerful. 

Plus the high damping factor toted by Alpine makes me think that the design of the PDX board isnt going to yield ANY better SQ than a SPL oriented amplifier. 

Okay how about you research some real SQ amplifiers like Tru and Arc's offerings and then compare your findings to the specs Alpine totes! If Alpine thoughtfully included any bit of their design towards SQ then they would be screaming it from the rooftops. 

I'm not trying to be an ass seriously... I am just surprised that this knowledge was being rejected. I was expecting super knowledgable folks on this forum.

Edit: yes I think that was before CEA compliance but I am living testimony that Alpine is full of horse excrement and I would give my hard earned money to a trusted company who doesn't seek such compliance seals.


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## 68962 (Aug 19, 2013)

Okay well I just saw the that techtronics no longer carries the rx1100.1 so yeah I would search out another good SQ amp for you but why would I do that??? Apparently a waste of my time since you know so much more about this stuff than me. If an Alpine is your #1 selection then I am certainly wasting my e-breath...

Edit: and I sound like a fanboy of what?? What are you even talking about? You are the one sounding as a fanboy might...


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## Kriszilla (Jul 1, 2013)

OneSpiritBrain said:


> I slammed Alpine to catch the OPs attention in hopes to make him aware that for the same amount of cash you can get a beefier amp that uses quality parts.
> 
> I've used Alpine amps and I'm telling you from experience that there are better products for less money.
> 
> ...


Now here's where the "less of an ass" approach works. It's when you provide real-world experience like you did above. That's helpful, and it gives us a better idea of why you recommend what you do.

Here's where I get a bit nit-picky about what may have happened, because it sounds so damn similar to something that happened to me several years back.

Hooked up an RF T10001BD rated for 1500+ on the birth cert, used DMM to set it at 1 OHM for 1200 RMS to start, fried the VC on my TC 12" sub 3 days later. At that point I could have sworn it was the amp. I left everything as was and grabbed a friend that had an O-Scope and checked the amp. 

Clipping was everywhere on that screen like a mofo. But, It wasn't the amp, it was my deck and my methods. I had set the gains on the amp with the HU volume too low and drove it to clipping when I increased the volume past the set point. Plus, the test tone that I used wasn't at the proper DB rating which further skewed the gain setting.

Luckily it was the sub and not my Focal K2P comps on the other RF amp that I had set the same way.

Lesson learned. 

When you fry a speaker, you can't just look at the amp, you have to step back and look at EVERYTHING in the chain that either originates, modifies, or touches that signal until it reaches the speakers. 

That goes for any brand of equipment that one uses.


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## garysummers (Oct 25, 2010)

As I stated in another thread I run 5 PDX amplifiers and they sound very good. Had the originals first then upgraded to the new. Major improvements.

http://www.diymobileaudio.com/forum...io-hd600-4channel-amp-final-system-newv5b.jpg


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## ChrisB (Jul 3, 2008)

I tried to run a PDX-5 and a PDX-V9. Both had noise issues that were easily remedied by replacing them with other amplifiers.


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## Kriszilla (Jul 1, 2013)

ChrisB said:


> I tried to run a PDX-5 and a PDX-V9. Both had noise issues that were easily remedied by replacing them with other amplifiers.


My V9 is quiet as a mouse, but I have heard of noise issues in some of the older PDX models. I'm about to pick up another V9 to complete my system and I hope it's as solid as the one I have now.


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## therapture (Jan 31, 2013)

Yes, my V9 is also dead quiet.


OneSpiritBrain, thanks for changing your direction, it originally was quite lame. 

I still disagree with some of your points, I never said Alpine was the BEST, but they certainly are not crap amps, and you may have had other issues, or even a defective amp.


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## ChrisB (Jul 3, 2008)

I was just trying to point out that I am 0 for 2 with properly functioning Alpine PDX amplifiers. They are going to have to do some heavy convincing to get me to shell out money a third time!

EDIT: Their subwoofer amplifiers may be a safer bet, but I'll never find out...


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## 68962 (Aug 19, 2013)

Kriszilla said:


> Now here's where the "less of an ass" approach works. It's when you provide real-world experience like you did above. That's helpful, and it gives us a better idea of why you recommend what you do.
> 
> Here's where I get a bit nit-picky about what may have happened, because it sounds so damn similar to something that happened to me several years back.
> 
> ...


This was years ago but IIRC I used the 3/4 rule on my hu which was a pioneer I paid $400 for and the sine was 0db or actually I think I had read to use a -3db for safety when setting gains blindly. I researched for close to a year before attempting a real, or so I thought, system. 

I used the exact same method to set the gains on that AQ-2200d and ran a HDC315 at around 900-1200wrms, didn't brace the box and impedance kept creeping up on me, with a year and a half beating that thing the VC was barely discolored and I sold it for exactly what I paid for it due to AQ's prices increasing  

I then ran an IDMAX12 in a solid box with minimal box rise and it saw +1100wrms daily. I, having developed OCD from that damn Alpine, checked the VCs on those subs way too much but to much avail because again no charring  

Anyways now I feel like an ass because your right I just assumed you all were blindly defending Alpine when it may very well have been my blind gain settings to begin with or hell maybe a bad amp... Sheesh I'm such a push over. Haha!

Okay so I'm having a hard time finding a decently priced SQ oriented amp... Give me some time and maybe I'll be able to locate one. You ever consider a/b instead of d?? I've never really researched the facts but I know in the highs and mids world I wouldn't use d circuitry. I bet if you did some serious research and maybe consider some of these new unknown companies you might find a powerful ab amp for a decent price that is going to give you a warm, accurate, correct nfb/damping balance amp that most d amps can't compete with, in terms of SQ.

I see that the OP stated that he purchased the PDX. Did you order it or pick it up somewhere? You install her yet???


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## 68962 (Aug 19, 2013)

Kriszilla said:


> Now here's where the "less of an ass" approach works. It's when you provide real-world experience like you did above. That's helpful, and it gives us a better idea of why you recommend what you do.
> 
> Here's where I get a bit nit-picky about what may have happened, because it sounds so damn similar to something that happened to me several years back.
> 
> ...


This was years ago but IIRC I used the 3/4 rule on my hu which was a pioneer I paid $400 for and the sine was 0db or actually I think I had read to use a -3db for safety when setting gains blindly. I researched for close to a year before attempting a real, or so I thought, system. 

I used the exact same method to set the gains on that AQ-2200d and ran a HDC315 at around 900-1200wrms, didn't brace the box and impedance kept creeping up on me, with a year and a half beating that thing the VC was barely discolored and I sold it for exactly what I paid for it due to AQ's prices increasing  

I then ran an IDMAX12 in a solid box with minimal box rise and it saw +1100wrms daily. I, having developed OCD from that damn Alpine, checked the VCs on those subs way too much but to much avail because again no charring  

Anyways now I feel like an ass because your right I just assumed you all were blindly defending Alpine when it may very well have been my blind gain settings to begin with or hell maybe a bad amp... Sheesh I'm such a push over. Haha!

Okay so I'm having a hard time finding a decently priced SQ oriented amp... Give me some time and maybe I'll be able to locate one. You ever consider a/b instead of d?? I've never really researched the facts but I know in the highs and mids world I wouldn't use d circuitry. I bet if you did some serious research and maybe consider some of these new unknown companies you might find a powerful ab amp for a decent price that is going to give you a warm, accurate, correct nfb/damping balance amp that most d amps can't compete with, in terms of SQ.

I see that the OP stated that he purchased the PDX. Did you order it or pick it up somewhere? You install her yet???

Edit: I must have hallucinated where he said he was buying the V9... Did you buy the MRX?


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## jim walter (Apr 10, 2010)

OneSpiritBrain said:


> Okay how about you research some real SQ amplifiers like Tru and Arc's offerings and then compare your findings to the specs Alpine totes!
> 
> If Alpine thoughtfully included any bit of their design towards SQ then they would be screaming it from the rooftops.


http://mobile.alpine-usa.com/mobile/product/pdx-f4

I think that qualifies as shouting it from the rooftops. Been up there since 2010. 

Don't take damping factor as the only 'selling point' of the PDX v2. There a lot more to the 'new' series than that. 

Jim 
/////Alpine


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## therapture (Jan 31, 2013)

While I am no pro, I do understand basic electrical theory, and how noise gets into car audio signal chains. I have one of the most noise prone cars out there, a Pontiac G8 GT, and I have not even done the "big three". I did use proper amp power and ground install specs, as well as basic signal wire separation from powerwire, and my car is absolutely dead quiet. No hiss, no hum. I think that speaks volumes about my V9's ability to reject noise as well as it's sound quality, which is the best I have had in 20 years of car audio. No fanboy here, this is actually my first Apine amplifier ever.


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## austin4heatwave (Feb 22, 2009)

how does one see discoloration of a vc without taking the woofer apart.........and also how do you check to see if your coils are becoming discolored without removal of the woofer and taking it apart? beyond that if your truly trying to help the op then pay attention to the fact that he isn't trying to spend the money for tru or arc gear he wanted to buy an amp under 300. also he doesnt live here in the states so not all of the stuff we have here is easily available to him. yeah he can order it and have it shipped but the shipping alone may put it out of his price range. just because you cooked a woofer using an alpine amp doesn't mean anything other than you cooked a woofer. many of us on this site have been around car audio forever. in 19yrs I have blown 2 woofers they were jbl loud + clear 12s on a kenwood amp I replaced them with 2 fultron 12s and never had another problem. by your logic jbl woofers are junk. do you see what im getting at. i have used alpine amps in my own cars on 3 different installs with no issues at all. i have installed 100s in other peoples cars along with Rockford mtx clarion diamond jbl kicker etc etc.....sometimes products make it to market doa or defective it happens sometimes we as people fk them up doesn't mean they are bad just that particular piece may have been.


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## 68962 (Aug 19, 2013)

I thought he said $400... 

Anyway yeah after 19yrs in car audio and you don't know how to visually check the health of a VC? wtf!?!? I hope you don't buy used woofers. I look at the VC before I install new woofers also.

I use 10-24/32 screws(1/4-20 if possible) and inserts for easy sub removal. You can gently and evenly lift the cone exposing the VC where the leads enter the coil. This is where heat damage is most apparent because the heat dissipates as it extends downward. Some subs you might have push down it depends on how the motor is hung. You view the coil through the cooling vents above the motor. 

Anyway I'm done haha

Good luck


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## austin4heatwave (Feb 22, 2009)

OneSpiritBrain said:


> I thought he said $400...
> 
> Anyway yeah after 19yrs in car audio and you don't know how to visually check the health of a VC? wtf!?!? I hope you don't buy used woofers. I look at the VC before I install new woofers also.
> 
> ...


use a dmm its faster.


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## Kriszilla (Jul 1, 2013)

austin4heatwave said:


> use a dmm its faster.


Yep. If there's any damage / permanent thermal stress on the VC, it's going to show in its resistance. Sometimes before it shows visually.


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## 68962 (Aug 19, 2013)

If you see impedance anomalies on a meter then the speaker is already toast. Heat from a clipped signal can char the varnish on a voice coil VERY quickly. Like in one short sitting... It's actually a pretty damn good clipping detector. I'm not going to go in to why clipping creates so much heat because you surely already know that. 

At the end of this day, as it approaches, I think there is a new place in my mind for super tech r&d like that which is seen at Alpine and JL... I read some interesting threads on Manville's ideas and implementation in JL's /amps and I assume this same sophisticated level of r&d is going in to Alpine's amps.

There seems to be a place for such an amp in my front stage in the future. This forum redeemed itself in my eyes. Already a intriguing place, hmmm.


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## austin4heatwave (Feb 22, 2009)

same thing goes if there is visual damage. copper itself isn't what burns the adhesive is what burns so if you have "discolored" your coils then you have damaged what bonds the cols to the former. you can achieve this with clipped or clean power


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## cleansoundz (May 14, 2008)

Good information.


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## I Love BMW (Sep 7, 2013)

I have nothing but good things to say about the mrx line. I used my zapco c2k to compare on my mids and tweets in my 3 way up front setup and couldnt tell the difference between the two. I am now a believer in class d power! 


Sent from my iPhone using Tapatalk


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## cleansoundz (May 14, 2008)

You should try the new Alpine PDR F50. That is an excellent class D amp for mids and highs.


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## I Love BMW (Sep 7, 2013)

cleansoundz said:


> You should try the new Alpine PDR F50. That is an excellent class D amp for mids and highs.



I was wondering whats the deal with those amps. Great to hear that so when i upgrade if i do later down the road


Sent from my iPhone using Tapatalk


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## buguy (Aug 5, 2014)

I looked at those when I was looking at PDX amps. Do you think the PDR is enough of an improvent over the PDX to justify the cost difference? Looks like the PDR is [email protected] and the PDX F4 is [email protected], and the PDR looks like its about $150 more than the F4.


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## cleansoundz (May 14, 2008)

buguy said:


> I looked at those when I was looking at PDX amps. Do you think the PDR is enough of an improvent over the PDX to justify the cost difference? Looks like the PDR is [email protected] and the PDX F4 is [email protected], and the PDR looks like its about $150 more than the F4.


I didn't like the sound from my F4 as much as the PDR F50. The F50 bought better midbass to my separates. In reality the PDR 50 is underrated. You will never hear the difference in watts between the two. The PDR was designed to be in direct competition with JL Audios XD line. Owning the JL XD 400/4 v2 and the PDR F50, to my ears they both sound the same.


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