PPP - MultiWave and THD

jdandy · #1 05-22-2009, 09:00 PM

Jim (Stillone) made a comment this evening in another thread about his two Power Plant Premier's, and what they are sounding like in his system. His comment, "They have changed the sound and most things are better, but something now seems to be missing", grabbed my attention. He went on to say, "Where I am struggling is with the all of the gains such as vocal detail, a bit of bass and some quieter background, I seemed to have lost a sense of pace and energy."

I am hoping that this thread will open a discussion to see if anyone else is experiencing anything similar. I am not having this experience, in fact just the opposite. The things that Jim said he gained, greater vocal detail, a thicker bass texture, and a deeper sense of silence, I have gained as well, but without the loss of energy, which I am assuming to mean a certain level of dynamics. This is why I asked Jim if he was using MultiWave output. I use the MultiWave output on the PPP dedicated to my two MC501 amps, but I do not use MultiWave on the PPP dedicated to my sources. It has been my experience that there seems to be a bit more dynamic range, particularly in the mid to upper midrange area of the audio spectrum when MultiWave output is selected on the PPP that powers the amps.

Jim has said that when he puts his PPP's into MultiWave output that his THD is raised on the output, and significantly. If I remember correctly, the additional THD was more than 1%. I tested this with both of my Power Plant Premiers in the main system, and only saw a .1% increase in output THD, and sometimes none at all when I switched to MultiWave. This raises my curiosity. Why are Jim's PPP's increasing the output THD when switched to MultiWave output? Is anyone else experiencing an increase in output THD when switching to MultiWave output? Something doesn't seem right to me.

Power Plant Premier owners, kindly take a few moments to switch your units to MultiWave output, and then to normal sine wave output, while checking the output THD in both output modes. I am interested in discovering any differences in output THD between sine wave output and MultiWave. Please let me know your THD numbers.

Perhaps Ryan can chime in, and let us know if MultiWave output typically increases output THD.

gregswaim · #2 05-22-2009, 09:42 PM

This is a very interesting find. Considering most on this forum have high current amplifiers with mega watts of output it would seem appropriate to have such device as the PS Audio PPP.
For me, I've never noticed a difference with such things beyond a simple surge protection device for both my wall outlet and additional after market variety. My MC2102/MA6500 does not draw near the amperes that the mega watt amps do.

Masterlu · #3 05-22-2009, 10:06 PM

I will check a few of mine that are easy to get to.

jdandy · #4 05-22-2009, 10:28 PM

I just rechecked the PPP that powers my two MC501's. I have .5% THD output whether MultiWave is on or off. I tried the same thing with the PPP that powers my preamp and sources. The same, .5% THD output whether MultiWave is on or off.

This is why I am perplexed at what Jim has said about his two PPP's increasing in THD output with MultiWave on. I want to be able to solve this issue. Perhaps Jim is experiencing a problem, but I would hardly think it would be the same on two seperate PPP's.

Masterlu · #5 05-22-2009, 10:39 PM

OK, I just checked 6 of my units; .3% THD output whether MultiWave is on or off.

Still-One · #6 05-22-2009, 11:19 PM

Sorry guys. I have been watching the Hockey Playoffs and just came back to check what has been happening this evening.

Thanks to Dan for starting this thread. I read the posts here and so I again checked the THD. As noted earlier my THD with MW off both PPP's show about 0.8% to 1% corrected. I switched MW back on and it jumped to 1.5%. There does not seem to be any difference in the base THD when MW is turned on.
Jim

jdandy · #7 05-22-2009, 11:20 PM

Thanks, Ivan. Your THD numbers look very good.

I went back and was reading Jim's comments in the PPP - Cleanwave & MultiWave thread. He stated, "Without multi-wave and depending on the time of day distortion out is about .8%, with multi wave it is about 1.7%. Remember I noted that after running cleanwave one time, my distortion figures had risen too."

After reading his comment about his THD rising after running CleanWave, I tried that with both of my main system PPP's tonight. I muted the system, pressed the CleanWave button on the remote, and went through the 5 second CleanWave cycle. I am now back to listening to music, and my THD output for both PPP's is still .5% whether the MultiWave is on or off.

Jim, have you tried the PPP's straight to the wall, bypassing the APC power supply. Perhaps the APC unit is introducing some form of distortion. At this point I am just guessing, sort of going through a process of elimination.

Masterlu · #8 05-22-2009, 11:26 PM

I agree, try bypassing the APC unit & let us know the results.

Still-One · #9 05-22-2009, 11:26 PM

The APC is only used on my sources Airport Express and SonoS unit. They are on their own 15 amp circuit.

I just re-ran CW and this time it had no impact on the before or after THD. This only occurred the fist time I ran CW>

Masterlu · #10 05-22-2009, 11:29 PM

Something is odd, your 2 PPP's came from a large lot of which I kept most of them. Feel free to call me over the long weekend Jim.

You know me service 24/7

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