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racer808

Class D / Class A/B?

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racer808

I have 3 precision power Class D amps. I have a the ppi900.4 bridged running my Pro80's, the ppi600.2 running my MB8.s & the ppi900.5 running interior. My system is loud, clear & it bumps but I have to have my deck volume round 27-31 for wakeboarding loud. My buddy is running a pair of Rev10's with JL audio amps class A/B and his deck at 20-21 is much louder than mine on the tower. Adding it up we both have approx 400 watts going to our respective tower speakers, except I have 200 at my MB8's.

Are these PPI amps not as powerful as we thought? Are class A/B just louder? Are the Rev 10's just that much better? I'm just curious, no plans to change anything, my next upgrade is FAE, but it had me wondering

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MLA

The class-D or class-A/B power side of the amps do not directly dictate the output to the speakers. In other words, you dont automatically get more/less power with one topology over the other, thats all about efficiency.

2nd, you are comparing an 8" HLCD to the 10" HLCD. Size matters

3rd, what JL amp model? Kinda hard to compare model X from brand A to model ??? of brand B

4th, yes, the PPi are not quite the RMS output advertised. But even then, it take a decent difference in wattage to make an audible difference. Without knowing what model amp your buddy is running, its hard to tell, but I doubt this is were the difference is.

5th, tuning can play a part. His gains may be too high, thus he reaches his pre-clip volume level at a lower point on the head-unit dial. or, your gains are too low and you are leaving power on the table, even with the head-unit at near 100% volume level

6th, what the line level output of each head-unit

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skyskier

All watts are not created equal. I have thrown a lot of money at that theory over the years and found it to be true. In general, it is not fair to compare the current model Precision Power amps to JL.

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shawndoggy

If you want yours as loud at 21 as it now is at 27, turn the deck to 21 and adjust the gains until it's as loud as you want it.

Then pray that you don't get someone at the controls who cranks it to 30 anyway.

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robtr8

You need to look at the respective sources first. If the two decks are not equal, then the volume numbers mean nothing. If they are equal, then look at how the gains are set. Either way, the systems should be "tuned" so that you get the full potential of the system without throwing square waves.

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David

I have 3 precision power Class D amps. I have a the ppi900.4 bridged running my Pro80's, the ppi600.2 running my MB8.s & the ppi900.5 running interior. My system is loud, clear & it bumps but I have to have my deck volume round 27-31 for wakeboarding loud. My buddy is running a pair of Rev10's with JL audio amps class A/B and his deck at 20-21 is much louder than mine on the tower. Adding it up we both have approx 400 watts going to our respective tower speakers, except I have 200 at my MB8's.

Are these PPI amps not as powerful as we thought? Are class A/B just louder? Are the Rev 10's just that much better? I'm just curious, no plans to change anything, my next upgrade is FAE, but it had me wondering

You may have several issues.

Your gains could be set just a bit conservative, but if your HU goes to 35 for example, then 29 to 30 is typically a good maximum non-clipping number. Some go full rotation without preamp clipping while some can't go beyond 80 percent without getting a bit edgy. The gain of your downloads could be different also.

There's not necessarily an audible difference in Class topologies in general but there are vast degrees of quality differences within each Class whether by brand or price point.

It takes a pretty big jump in measurable power to hear a noticable volume difference but there are other quality issues that can definitely impact your perception.

The MB8 midbass speaker certainly alters the warmth and balance but does little to add perceived output since it's not fullrange. This option is more about the quality of near field listening rather than projecting at wake range.

Some amplifiers simply do not sound good bridged fullrange. They work fine for a heavier and slower lowpass subwoofer on mono material but their circuit design in a bridged push/pull fullrange arrangement presents an aysemmetrical signal at the speaker terminals which sounds bad but also leaves a little gain on the table. Unfortunately there can be such a disconnect between the foriegn builders and the domestic importers (pure sales and marketing with no engineering) that these issues don't get addressed.

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David

Also, I forgot to mention, that if you are splitting up your preamp between several inputs of several amplifiers to the tower, you may not have adequate voltage. You may need a boost. And, check the manual on your amplifiers to see if you have a pass-through output RCA set on one of them that has a buffered output rather than just a 'Y' division.

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Roster man

"4th, yes, the PPi are not quite the RMS output advertised. But even then, it take a decent difference in wattage to make an audible difference"

Hate to burst you bubble but they actuall are underrated and exceed the cea 2006 ratings. See independent test lab review below:

http://www.pasmag.com/car-audio/test-reports/1805-test-report-precision-power-p9004-amplifier-[quote name="MLA" post="647599" timestamp=

I have the polk versions and they have tons of power and put off very little heat. Small footprint and high efficiency so batteries last longer.

Edited by Roster man

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nyryan2001

I've had the Fosgate T600-4, NVX, Arc 300.4, PPI900 and now finally the Arc600.2 on Rev10s.

By far, 600.2 smokes them all handily.

The NVX and PPI were nearly identical in performance...decent, but I felt the amps lacked some warmth in the sound. Can't be beat for the price though.... But completely disagree... Either bridged or ohm'd down, they get HOT.

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Bobby Light

I've had the Fosgate T600-4, NVX, Arc 300.4, PPI900 and now finally the Arc600.2 on Rev10s.

By far, 600.2 smokes them all handily.

The NVX and PPI were nearly identical in performance...decent, but I felt the amps lacked some warmth in the sound. Can't be beat for the price though.... But completely disagree... Either bridged or ohm'd down, they get HOT.

I sure hope it does, it's quite a bit more power than any of the amps you listed, in some cases 100% more power.

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MLA

"4th, yes, the PPi are not quite the RMS output advertised. But even then, it take a decent difference in wattage to make an audible difference"

Hate to burst you bubble but they actuall are underrated and exceed the cea 2006 ratings. See independent test lab review below:

http://www.pasmag.com/car-audio/test-reports/1805-test-report-precision-power-p9004-amplifier-[quote name="MLA" post="647599" timestamp=

I have the polk versions and they have tons of power and put off very little heat. Small footprint and high efficiency so batteries last longer.

No sweat. Its always nice to see someone do some research and vet a product, rather then blindly take the word of the manufacturer on its perfomrance. I do not have the means to measure an amps power, but it and the polk seemed to lack something that higher end amps with less advertised power,

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nyryan2001

I sure hope it does, it's quite a bit more power than any of the amps you listed, in some cases 100% more power.

No, I have them at [email protected]

Both the NVX and PPI spec that or better. Point was I was trying to make it pure bench tested watts doesn't tell the whole story, lacked warmth. And they certainly are not cool running ultra efficient amps like he reports in his review. I know he got pretty good tested efficiency numbers, but I've never ran amp that normally ran so hot...but they never did cut out.... NVX or the PPI. So hot you couldn't keep you hand on it, regardless of ambient temps.... From a few mins of hard play.

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David

While Class D is 60% more efficient than Class AB and generates perhaps one/fourth of the heat per amount of current drawn, the identical Class D is usually placed in a heatsink that is one/fourth the mass. So a Class D can get just as hot as a Class AB regardless of the higher efficiency.

Yes, amplifiers of the same power, or even of the same topology class can sound different. The simple power measurements don't tell you what the amplifier does with complex signals, or at frequencies other than the 1 kHz sine wave test signal, or what kind of negative feedback the designer uses to lower the distortion or to extend the top end response.

Every class of amplifier has some inherent flaw. It's how that particular amplifier is designed that makes a difference.

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Bobby Light

No, I have them at [email protected]

Both the NVX and PPI spec that or better. Point was I was trying to make it pure bench tested watts doesn't tell the whole story, lacked warmth. And they certainly are not cool running ultra efficient amps like he reports in his review. I know he got pretty good tested efficiency numbers, but I've never ran amp that normally ran so hot...but they never did cut out.... NVX or the PPI. So hot you couldn't keep you hand on it, regardless of ambient temps.... From a few mins of hard play.

I get it and I wasn't trying to call you out or anything just making an observation. There is a difference running an amp ballz out to get your 400 watts vs an amp capeable of producing 1200 and running it in cruise control getting 400, that's alot of headroom you didn't have with the other amps.

Edit: And yeah I haven't heard to many class D amps I consider to be good sounding.

Edited by Bobby Light

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