Alpine PDX vs. JBL GTO

[SantaCruz Zak]

Hello all- I am currently running a JL 12W3 2-0hm sub off a new Alpine PDX 1.600. The sub s rated at 500 rms, and although the amp is rated at 600 rms @ 2 ohms, the birthsheet shows it tested out a almost 700 rms. It is so much power for my little Mazda 3 hatchback. I have the gain on the amp set between 3 and 4! I am about to install some Polk MM6501 components and an Alpine PDX 4.100 amp that I scored on craigslist for a great deal. My headlights are already dimming from the sub amp alone. I am considering selling the Alpine amps and getting a 3 or 5 channel amp to run everything. I am looking at the new JBL GTO-5EZ. I would be bridging it to get 150rms in the front, as I am not planning on running the rear speakers. 500 would be going to the sub. Would this be a good choice? I know the PDX are top of the line digital amps, and the JBL is more mid-grade. I am running off the stock head unit right now, so even though the sub amp is quality, the sq is leaving a lot to be desired.

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[chillin 10+ year member]

your sub may not be quite as loud and if you are still pulling the same or more watts as you are now, the dimming will still be happening. Have you done the big 3 upgrade? if not, do that first

 

[gunz4me2 10+ year member]

The Big 3 wiring upgrade is not going to magically help his stock 125 amp alternator produce more current.

Now if you are talking AGM battery, alternator, and upgraded wiring, i.e. the REAL Big 3, that would help.

 

[chillin 10+ year member]

If he has 125 amp alt, he shouldn't be having problems with less than 700 watts

 

[SantaCruz Zak]

Headlights only dim when I get it pumping. I have 4 ga power and ground. If I go with hooking up the second amp, I'll have to spend another $100 on 0/2 ga wire. The JBL amp only needs 4 ga. I am thinking I could sell my Alpine amps for more than the price of the JBL amp, and keep my existing wiring. I am just not sure if the quality of JBL will be on par with the Alpines.

 

[gunz4me2 10+ year member]

If he has 125 amp alt, he shouldn't be having problems with less than 700 watts

Oh snap, he could have one of the older Mazda 3s that has a 90 amp max alternator versus the newer ones that are 125 amps max. That's the thing about those stock alternators, many toss out a peak number at an RPM range close to red line versus normal driving RPM. In other words, the OP's charging amperage could be significantly lower when driving around. Regardless, the power and ground upgrades are not going to address the lack of amperage to keep the bass pumping.

To the OP, if you have an older PDX 4.100, I'd highly recommend selling it off. I had nothing but fits with regards to noise issues on a circa 2008 PDX-5 that I used for all of 15 minutes before boxing it back up to return it. It produced hiss on digital silence and the hiss was noticeable between tracks. That was truly annoying and adding to the fact that it literally sưcked out my midbass, I could not in good faith recommend the older PDX amplifiers. The newer ones, starting with the F and M series, are much better!

 

[SantaCruz Zak]

I think I do indeed have the 90 amp alternator. It is a 2008.5 Mazda 3 2.3L. The JBL amp only has three 30A fuses on it though. It seems to me that this amp would draw less than the two Alpine amps. Thanks for your help guys, it is much appreciated.

 

[wenn_du_weinst 10+ year member]

http://www.caraudio.com/forums/amplifiers/206351-why-gain-setting.html

 

[BnGRacing 10+ year member]

I am considering selling the Alpine amps and getting a 3 or 5 channel amp to run everything.

You won't regret that decision at all.

If I were to replace my Xtant 3300c, I'd snag the new JL XD 3ch or Arc Audio's 3ch. Tiny things. And don't worry about thinking you HAVE to send that JL woofer 500w. That's kind of a bogus number as JL changed their ratings on all their subs b/c internet forum experts think a 500w sticker on a sub is better than a 300w sticker. With the W3, a slightly larger box than 'spec' and 2-300w is all that's needed. You won't get any louder or sound any better with a 500w amp in a 'spec' box. All you'll be doing is heating the woofer up more.

If you ever get to the point where you wished you got a 5ch so you can amp your rears; go buy some sand resistors and run the fronts & rears in parallel. That will effectively attenuate them and you'll be good to go.

I have nothing but horror stories with PDX amps (and most high end Alpine amps actually). Sure, 'they say' the newer ones are better but I'm not about to spend that kinda coin to find out if that statement is true. Then again, "better" isn't really saying much b/c those older PDX amps sounded like garbage. Terrible processing made everything sound like a poorly compressed MP3 and subs sounded really dry.