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Thread: Precision Power PPI Phantom P900.4 fullrange class D

  1. #1
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    Precision Power PPI Phantom P900.4 fullrange class D

    Precision Power PPI P900.4

    I am always on the lookout for amps that fit my requirements of:
    -power
    -size
    -cost
    -features
    -Reliability (this has to be determined in the long run and after purchase in the real world)

    That is the order of importance for me, however size and cost is a balancing act. I can be swayed to spend a little bit more than my normal ways if the size/form factor is appealing enough. I keep a couple of extra amps laying around for backup purposes and form factor reasons, not for voodoo inaudible "SQ" beliefs, so this will hopefully replace 2 amps if all goes well due to size...cost was equal to the 2 amps combined.

    Specs:
    POWER OUTPUT @ 1.0% THD, 14.4V
    145W x 4 @ 4ohm
    225W x 4 @ 2ohm
    450W x 2 @ 4ohm

    Size: Small

    Filters:
    HP/LP/BP 20hz-5Khz Yep, bandpass.


    Good:


    Sounds fine, no noise issues even at low volume. No turn on noise, no turn off noise. Much better in terms of noise compared to 2 refurbed planet Audio BB150.4's I gave a test run to years ago.

    Stayed cool running fullrange with 8 ohm drivers (to be expected). Next I need to test in the case of why I bought it, bridged midbass duty.


    Gripes:
    -End caps get in the way of the screws.

    -Mounting holes are too small to accommodate a normal screw. Supplied screws have small heads and only show 2-3 threads sticking out the bottom. I'd be worried it would actually hold an amp in place, especially if you need to screw through multiple materials. Be prepared to scar the mounting holes using other screws.

    -Adjustment knobs, they are philips head which is nice because it matches the terminal screws requiring only a single screwdriver for installation, however I would prefer in order of preference, knobs with arrows, single slot, last philips.

    -Gain sensitivity. I would require a lower input range for my needs however most people with strong line voltage will probably be ok. My carpc soundcard has <1V output, so I am a minority in the market. No sure if I am able to get full rated power. In theory I should, but output seems a bit low compared to a Soundstream Ref604 it replaced that had a lower sensitivity range of 100mV.

    Link to bench measurements below


    PASMAG review
    PASMAG | PERFORMANCE AUTO AND SOUND - Test Report: Precision Power P900.4 Amplifier



    Manufacturers Rated Power Actual Measured Power Actual Measured Power

    @* 1.0% THD+N***********@ 12.6V Battery @* 1.0% THD+N***@ 14.4V Battery
    145 x 4 @ 4 ? 113 x 4 @ 4 ? 150 x 4 @ 4 ?
    225 x 4 @ 2 ? 179 x 4 @ 2 ? 235 x 4 @ 2 ?
    450 x 2 @ 4 ? 363 x 2 @ 4 ? 477 x 2 @ 4 ?

    Signal to Noise Ratio referenced to 2V output. -82.0dBA

    (CEA-2006A) (1 watt @ 4 ohms)
    Signal to Noise Ratio referenced to full output. -103.8dBA
    THD+N at rated 4 ohm power 0.55%
    CEA-2006A rated 4 ohm Power (minimum power per channel developed over the entire intended audio bandwidth) 131 Watts
    Maximum Efficiency at full 4 ohm power per ch. 83.00%
    Maximum Efficiency at full 2 ohm power per ch. 75.80%
    Efficiency at* 10 watts per channel, 4 ohms 60.40%
    Idle Current 1.5A
    Input Sensitivity 280mV- 7.7V
    Maximum Current @ full power, lowest rated impedance 86.1A
    Frequency Response (-3dB) <10Hz – 34.3kHz
    High Pass Crossover 15Hz – 4kHz

    -12dB/Oct
    Low Pass Crossover 50Hz – 5kHz

    -12dB/Oct
    Subsonic Filter None
    Bass Boost None





  2. #2
    Senior Member cvjoint's Avatar
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    That is one solid amplifier. Thanks for the review, it's complete with everything, even a bench test and innards. A++

    I was thinking of getting the JL XD series but now you got me thinking of these. Have you looked at the JL? What are your thoughts?

    Also would it be too much for you to weigh one for me? Sonix says they are 4lbs each, that's really really light. If you could confirm that would be super.

  3. #3
    Member hottcakes's Avatar
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    nevermind, perhaps i should've checked the link first.
    i should really stay off of forums after a few drinks.

  4. #4
    Senior Member cvjoint's Avatar
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    So the drawbacks as far as I can tell are:
    *needs high voltage head
    *crosstalk is fairly high
    *damping factor is fairly low

    I don't really know if any of these are bad enough to make it a problem. I know my P99 deck will give it enough voltage. The crosstalk maybe you can check with the balance on your deck. Damping factor is low compared to JL, Alpine offerings but over 100, so again maybe not a problem.

  5. #5
    The xover section is what has me impressed. That 10x multiplier button on both sets of channels would make for some interesting combos.

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    Quote Originally Posted by cvjoint View Post
    So the drawbacks as far as I can tell are:
    *needs high voltage head
    Wouldn't say need. More like nice to have so you have a bit more usable range on the gain knob. I don't like having to use only the bottom end of the scale.

    *crosstalk is fairly high
    Crosstalk audibility threshold for humans has been stated to be somewhere around 30dB. Box says 32dB, Grizz said 32dB at 1Khz, however the identical Polk version D4000.4 tested by Garry also shows -32dB, but only up near 20Khz. At 1Khz -62dB which is comparable to lots and lots of amps on the market past and present. yes this is me saying Polk D4000.4 ~ PPI P900.4 until someone proves me otherwise.

    PASMAG | PERFORMANCE AUTO AND SOUND - Test Report: Polk Audio PA D4000.4 Amplifier


    *damping factor is fairly low
    Eh...not going to touch this one. I'd prefer to see what happens with a full on 20hz test tone measurement rather then a sweep to see if it can hold up the low end. I asked Garry about this and he generates 15 page test reports and has a power cube, but I venture to guess the magazine only publishes what they want. I'd like to see if power out sags at all at the top and bottom ends similar to what AVSforum was doing with their proamp testing methodology. It doesn't have a ton of rail capacitance so it may sag if the power supply or protection circuits alter it to prevent meltdown.

    I don't really know if any of these are bad enough to make it a problem. I know my P99 deck will give it enough voltage. The crosstalk maybe you can check with the balance on your deck. Damping factor is low compared to JL, Alpine offerings but over 100, so again maybe not a problem.
    You have more crosstalk created by the playback method and environment.

    If you don't like the PPI version, take your pick between Polk D4000.4, Hertz HDP4, Ampire MX4, and who knows who else. All seem to be using same basic board with some preamp/crossover function tweaks.

    I will get back to you on weight, but sounds about right.
    Last edited by durwood; 11-14-2011 at 02:25 PM.

  7. #7
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    Quote Originally Posted by bassfromspace View Post
    The xover section is what has me impressed. That 10x multiplier button on both sets of channels would make for some interesting combos.
    Bandpass too. Nice backup if the DSP ever goes down or you want one less piece of gear.

  8. #8
    Senior Member cvjoint's Avatar
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    Quote Originally Posted by durwood View Post
    Wouldn't say need. More like nice to have so you have a bit more usable range on the gain knob. I don't like having to use only the bottom end of the scale.


    Crosstalk audibility threshold for humans has been stated to be somewhere around 30dB. Box says 32dB, Grizz said 32dB at 1Khz, however the identical Polk version D4000.4 tested by Garry also shows -32dB, but only up near 20Khz. At 1Khz -62dB which is comparable to lots and lots of amps on the market past and present. yes this is me saying Polk D4000.4 ~ PPI P900.4 until someone proves me otherwise.

    PASMAG | PERFORMANCE AUTO AND SOUND - Test Report: Polk Audio PA D4000.4 Amplifier




    Eh...not going to touch this one. I'd prefer to see what happens with a full on 20hz test tone measurement rather then a sweep to see if it can hold up the low end. I asked Garry about this and he generates 15 page test reports and has a power cube, but I venture to guess the magazine only publishes what they want. I'd like to see if power out sags at all at the top and bottom ends similar to what AVSforum was doing with their proamp testing methodology. It doesn't have a ton of rail capacitance so it may sag if the power supply or protection circuits alter it to prevent meltdown.



    You have more crosstalk created by the playback method and environment.

    If you don't like the PPI version, take your pick between Polk D4000.4, Hertz HDP4, Ampire MX4, and who knows who else. All seem to be using same basic board with some preamp/crossover function tweaks.

    I will get back to you on weight, but sounds about right.
    So you are fairly convinced they don't touch the board, ppi = polk. After the quiet few days on the diy thread I'd say they are the same as well. I was really trying to force his hand a bit. Since the PPI tested better he's probably wise not saying anything, that's what I'd do. It also makes no sense to spend extra money modifying a design just to sell it cheaper with a more gimmicky heatsink.

    If you go out and add the two test result there is also a damping factor with the Polk, 113 if I remember correctly.

    If I get two of these, should I run:
    1. one amplifier for midbass, mid, tweeter left and the other for right speakers,
    2.midbasses on one, mids and tweeters on the other?

    The first option would give me better separation of right and left in case it is a slight issue. The latter would split the power demands equally between the amps giving the power supplies a break.

    Thanks for the response.

  9. #9
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    Quote Originally Posted by cvjoint View Post
    So you are fairly convinced they don't touch the board, ppi = polk. After the quiet few days on the diy thread I'd say they are the same as well. I was really trying to force his hand a bit. Since the PPI tested better he's probably wise not saying anything, that's what I'd do. It also makes no sense to spend extra money modifying a design just to sell it cheaper with a more gimmicky heatsink.
    I don't work in the circuit board MFGing business, but seeing internals of a Hertz HDP4 and an Ampire MX4, and the 5 channel polk...the boards look nearly identical. The types of parts are different on some but that could a be for a couple reasons.

    a) They are common designs either off-the-shelf, or engineering firm designed and built in the same MFGing facility, you pay more or less depending on part type. Maybe one uses more reliable parts, maybe one uses higher tolerance, maybe they the supplier guarantees a certain warranty/longevity and therefore uses parts that will ensure it meets this spec offered to the customer (POLK, PPI, HERTZ, etc) so it does not have to pay for certain warranty costs.

    b) Engineering firm designed and licensed design built at different facilities, which could explain different part types, etc.

    In this day and age, it is not uncommon for either of these scenarios. It up to marketing to determine how to handle product comparisions and how they want to spin it when brought to light.

    If I get two of these, should I run:
    1. one amplifier for midbass, mid, tweeter left and the other for right speakers,
    2.midbasses on one, mids and tweeters on the other?

    The first option would give me better separation of right and left in case it is a slight issue. The latter would split the power demands equally between the amps giving the power supplies a break.
    I would probably opt for option 1 for your reasons given for number 2. Mids and tweets are light loads on a power supply usually, whereas lower frequencies are not. Option 2 loads down the power supply of one amp but not the other. Try both, but my vote goes for Option 2, but not because of channel separation...only for even load distribution. Also by doing that, you get L/R level controls and combined with bandpass would make for active system that have the basic functions you need.
    Last edited by durwood; 11-14-2011 at 04:29 PM.

  10. #10
    Senior Member cvjoint's Avatar
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    Thanks but I think I'll go for the Hertz, the logo is backlit and I can rotate it.

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