PS Audio PPP Question about (THD)

SolidSqual
SolidSqual Posts: 5,218
edited November 2008 in Electronics
I'm posting this here because the PS Audio site seems a bit slow to respond.

My PSA PPP has a Total Harmonic Distortion (THD) of 1.8 at the input and from 1.8 to as much as 3.0 (real bass heavy music) at the output. IS this normal? Shouldn't the THD be less from the output? I'm confused. Can someone please set me straight. I just want to make sure m unit is working right.

Also, does anyone own one of these? Does yours get real hot too? When do your fan turn on? Mine's pretty hot, but the fan doesn't really come on.

Thanks,

Mike
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited November 2008
    SolidSqual wrote: »
    I'm posting this here because the PS Audio site seems a bit slow to respond.

    My PSA PPP has a Total Harmonic Distortion (THD) of 1.8 at the input and from 1.8 to as much as 3.0 (real bass heavy music) at the output. IS this normal? Shouldn't the THD be less from the output? I'm confused. Can someone please set me straight. I just want to make sure m unit is working right.

    Also, does anyone own one of these? Does yours get real hot too? When do your fan turn on? Mine's pretty hot, but the fan doesn't really come on.

    Thanks,

    Mike

    I have three PPP's. Two power the amps, plasma TV and source components in my home theater system and the third powers the source components in my two channel system. Mine get barely warm when idling and the two that have power amps connected to them get up to around 95 degrees F when pushed hard.

    The output THD should be much less than the input THD, typically the output THD is 1/9th to 1/10th that of the input THD.

    When the input THD = output THD, usually the PPP has gone into a protection mode and disconnected the AC regenerator circuit. It then needs to be rebooted.

    To reboot:

    1. Un-plug all components from the Premier.

    2. Unplug the PPP from the wall for thirty seconds or so.

    3. Plug the PPP back in to the wall, wait thirty seconds and power it up. Now check the output voltage and output distortion levels, they should return to normal. If they do return to normal, plug in your components.

    The PPP may have seen a line transient or some other line condition it didn't like. Have you recently added a new piece of equipment to the PPP, like a high current power amp?

    If you are using the PPP to switch on a power amp or other high current gear such as a plasma television, you might want to have their power ports set to delay.

    When you add up the potential power load for all the devices powered by your PPP, how close does it come to the PPP's 1500 watt max power rating? Some PPP users have achieved best results (relatively cool running with fans not coming on) by keeping the load under 70% (1050 watts). I have my HT PPP's loaded at 60% (900 watts).
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • SolidSqual
    SolidSqual Posts: 5,218
    edited November 2008
    Thanks! I completed the fist two steps and part of the third (haven't plugged gear back in). It is working properly again! But, how do I calculate the total wattage? Either I have too much on it or a spike I had last week popped the PPP and I never thought to reset it (nothing seemed wrong at the time).

    Right now I have my four monos, CDP, Behringer, Plasma, PS3 and HDR Receiver hooked up to it. Do you think I am running it too heavy?
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  • SolidSqual
    SolidSqual Posts: 5,218
    edited November 2008
    Talked to Barrow over at PS Audio. He says I'm good with all my 2-channel gear, but the addition of the Plasma and the HDR is putting me over, especially the plasma. So, I got those off the premier and am running well again. I may just buy a duet for the components off the premier.
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited November 2008
    SolidSqual wrote: »
    ...how do I calculate the total wattage?

    The specifications in the manuals should state how much power the units consume.

    For my 1st PPP I have:

    Plasma TV: 370 watts.
    Tuner: 19 watts.
    Blu-ray player: 33 watts.
    DVD player: 43 watts.
    Tuner antenna: 9 watts.
    Preamp/processor: 72 watts.
    Center channel amp: 350 watts.

    If everything is on, I have a load of 896 watts or 60% of the PPP's 1500 watt maximum.

    When watching movies only the following are used:

    Plasma TV: 370 watts.
    Blu-ray player: 33 watts.
    Preamp/processor: 72 watts.
    Center channel amp: 350 watts.

    This is a load of 825 watts or 55% of the PPP's 1500 watt maximum.

    SolidSqual wrote: »
    Right now I have my four monos, CDP, Behringer, Plasma, PS3 and HDR Receiver hooked up to it. Do you think I am running it too heavy?

    With four amps...possibly.

    Remember that for amps and other power hungry devices like plasma TV's, you need to leave some headroom on the PPP for peak power demands.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • SolidSqual
    SolidSqual Posts: 5,218
    edited November 2008
    After speaking with Barrow, he told me to monitor my PPP for a bit while nothing is plugged in to get an idea of what its regular THD output will be. Then add components one at a time starting with the source components and then amps. As long as the THD remains relatively unchanged then I am good. He indicated given the efficiency of my speakers, its highly unlikely that I'm using the total wattage of my amps.

    I'm gonna give this method a try and see what happens. I may have to buy a second PPP if I can't get my whole 2 channel rig on it. I'm taking all the video and TV related components off the PPP to gove me some headroom.

    Thanks for the tip on the power consumption. I'm going to go home and add them up.
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