PP12 struggling at times





Side question here - can someone let me know how to interpret the difference screen? What information can I gather from looking at it?


You can probably look at it in few ways, how well my PP works, or, how bad the input line is… The flatter the line, less work the PP has to do and better the input line is. If the difference is flat line, it means either you have a perfect input line or PP is not functioning…


That being said by Nordic I am wondering if that difference screen might be the best baseline screen to use when comparing with the issue event horizon and my fall into the performance abyss. I’m now anxiously waiting for the issue to happen again (never thought I would ever say that :-):face_with_raised_eyebrow:.


It is hard to judge from these screens as they have no scale indication. Knowing voltage in and out and frequency we can determine, but the difference screen, unless stated somewhere in the manual, is unknown, could be in volts and Hz or milivolts or MHz range. Also hard to understand how multiwave fits into difference and THD picture. For PS audio, most useful is, probably, the input voltage waveforms. We also don’t know how sensitive these scopes are, but at PS audio they do. They show a full sine period, but there could be a lot of things happening in that period, that PP is not sensitive to, or/and is unable to display. They are really just aids for something obvious.

On these screens you can see that the wave tops are chopped, but also raise and falls are asymmetric, that is probably most distortion is coming from. They should look parabolic as displayed on the out scope. Input wave actually looks a bit like a square wave through an L filter.


Thanks for sharing the pictures! Nordic’s interpretation of the difference screen is pretty spot on accurate. Essentially, it displays how far off the input voltage is from the perfect power the P12 is attempting to make.

The input voltage screen tells us the most generally, though the difference screen is also helpful.

What’s intriguing to me is that while the THD is the highest you’ve seen, the problem did not happen last night.


what exactly do you mean, “Those things are deadly?” I’m moving into a newly constructed house. It will have a smart meter.


My evening input THD on my P5 went from normally 2% to a steady %3.2 after they installed my smart meter. My scope now shows a slight flattening of the top of the sine wave as well. He may also be referring to the EMF effects.


I always wondered why P3 or P5 (P3 has P5 output stage I think) cannot rectify incoming mains to 0.1% thd as bigger brothers do. They always seem to sit at about 0.5%. Is this a firmware/marketing question?


My P5 gets my 3.2 input to 0.1 output.


I’ll concur. My P5 regenerates to .1.


Thanks goodness you have a Power Plant at the ready. That flat topping of the sine wave is what robs our systems of punch and life. At least you have a P5 to put it back to right again.

What does this “smart” meter do for you?


Did not mean to hijack the thread. My P3 never goes to 0.1. Input is 3%, output 0.5% with sine wave and 0.9% in multiwave mode. Have never seen it better.


Hi Paul I live in an area where we have smart meters. The meters determine an electricity charge based on “time of use” with peak loads being the most expensive. In my opinion they are idiotic and they don’t really affect usage patterns. It’s a way to get more money but say that it’s good for the environment.


You are correct. I will have to pay $24 per month up-charge to opt out.


Gotcha. So this isn’t something you went out and actively submitted. It’s an easier way for the utility to figure out how to charge you etc.


They send the usage data to the electric carrier via electronic signal. They do not have to employ meter readers any more. Another example of technology replacing people.


No worries about hijacking Nordic. Happy to see this thread go in all directions -let it go where it goes . I’m learning quickly and such an impressive group. Thank you all for your advice and help. Still no update from National Grid. They did say 2 weeks before they start analysis so that puts them starting work on Mon 2/18. However three nights in a row now with no issues and I’m starting to wonder if they must have made a call to the solar power farm. The Grid is not as transparent as I would like them to be, for example I can’t see the ticket I opened up…no access to see what they are doing if anything. I don’t want to call them and jinx it so I’ll sit tight.