555ps or npx300

Just a quick question really on them both.
Which one is now the better power supply?
They both use the same dr regulator’s i believe but with different transformers?
Obviously the 555 has an extra power rail, plus a clock out put if you need it, and so would be needed if you need them all but as far as that which is the better power supply.

I guess the newer transformer is a better design than the older one?
But what are your thoughts on this

I do not know…….but got the distinct impression the npx300 will not be used on the 500 series.

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I thought that the Naim guys already said that the NPX300 was better than the XPS DR, but not at the 555 PS level.


Yupp that’s correct.


I would expect the transformers are pretty similar… :thinking:
Not much has changed with their design or technology, for many years - decades even… :expressionless:

It was written somewhere that they use an slightly updated design/solution for the transformer in NC range. I believe it was said to mitigate transformer hum for example.

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Well it can’t be used on the ND555 as it doesn’t have enough power rails to power it all. You might be able to use 2 x npx300 maybe, i don’t know.
But i just wounded is the new npx300 is a bit quicker or not.
That was the reason for asking is the DR regulator’s the same, as if they are then the only difference is the transformer i think. Obviously these are different as for starters one has more windings for the extra 2 power rails as i mentioned in my first post.

But just because you cannot use it on the ND555 doesn’t make it any less good as far as a power supply goes.

The main reason NPX300 can’t be used on ND555 (and any other product with the PMC1704 DAC chip, such as NDAC, NDS, CDS and so on), is the lack of -10V rail, which is clearly a decision in line with the future technologies planned to be implemented.

Apart from that, I would say that the capacitors in 555PS are just a liiiittle bit bigger… :innocent:

555PS DR:


A picture says it all really.


The new one has much better heat sinks.

NPX 300 looks like a slightly grown up xpsdr. The daddy, is still the daddy.


I see the bigger caps, but not as many. So i guess that means each cap is supplying more than one power rail?
In the 300 it looks like each power rail has it’s own? If so then it looks like the 300 will be better separated from each other?
Again i can only guess as i am no expert on this.
But just because it has some big caps that doesn’t automatically mean better.

Where are you planning to plug it in?

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500 series is still the top stuff, might depend on what your plugging it into

I suspect specs mean less than how the component is used. Is the box (222/333/332) attached to the 555 or 300 getting full use of the PS? Unless you A/B holding all else equal you won’t really know which is better.

555PS has a monster bass, or it did when I had mine on a N-DAC with a HDX in front if it. So much so that I was tempted to remove the power line as that has a meaty bass as well. What is the signature of the 300 supply and is it as resolving as the 555PS.

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I’m banking on that being true as this is how I’m powering my 222 right now……sounds excellent by-the-way😀

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Mine sounds pretty great and it’s not even connected with the proper burndy.

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I demoed both on an NDX2. Both have as much extra detail, but they sounded very different. I would say they are closely matched, but it would be personal preference on which you choose. I went for the 555PS as it was ex dem and much cheaper. I also wasn’t confident in adding New Classic gear into my Classic system. Sometime mixing and matching different series doesn’t always work out. You think it all sounds great, but the synergy isn’t always there and you’re into listening fatigue after a few weeks.


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