PS555 vs. PS555DR

I am in the process of figuring out if I should get PS555 or PS555DR… ?

Planning to use it for Naim Ndac and CDS3.

Can someone tried those combo share some experience here ?

thanks a lot.

Have a read of my impressions of a newly serviced CDS3 on the CDS3 thread. I’ve just had the 555PS serviced & DRed - an expensive and lovely upgrade.

Best regards, BF

I prefer 555PS non-DR on my nDAC. Prefer it to a point that when I had it serviced, I kept it as non-DR.
For my NDS I use a DR version of 555PS.

I guest it’s horses for courses…

I got a new mechanism for my CDS3. I was told that it wouldn’t change the sound, and it didn’t. I got my 555PS DRed, but not serviced, later. What with the amount of time the PS was gone, possible burn-in differences, and my middle-aged memory, I couldn’t say for certain what any differences were.

Getting boxes serviced is a different matter, and mine have sounded better immediately.

CDS3/555PS or PS’/DR is a marvelous combination, fit to share rack space with my fairly-high-spec LP-12. I haven’t heard the CDP with any other PS.

I just added a 555PS to my CDS3 and it is a large improvement. More immediacy and resolution. Not sure DR is a wise option since I have an active system, and would require 4 additional boxes DRed .

Was a PS555 a significant upgrade to your Ndac?

Given 3-4x the price relative to Ndac, I am still contemplating whether PS555 is justifiable…

Yes - it was. It’s difficult to describe the effect without using all the superlatives in the English dictionary :slight_smile:
The best way is to use an analogy - think of it as a huge turbo-charger on a car’s engine, with all the uplift in performance and no turbo-lag :slight_smile:

As to a cost - I bought my 555PS as a pre-loved one from a very reputable UK dealer and had it serviced at Class A. All for around 60% of a price of a new XPS DR. So it was a good value for money.

Thanks a lot Adam,

The hum sound issue seems to be pretty common. Does yours have it? Some say a power conditioner might solve the problem. Are you using any?

I am trying to do all the possible due D research before spending US$4k on this 555PS.

Thanks a lot in advance.

I traded an XPS for a 555PSDR to power my DAC, and was very pleased, as was Adam. I will not comment on cost, but the bigger supply brought out more music, more dynamics, with quieter background. All of this, using only one Burndy out of the PS. I realized more from this investment a few years later, when I traded the DAC for a used NDS - using both Burndy’s from the 555PSDR.


Thanks Adam,

The hum sound issue seems to be pretty common. Does yours have it? Can other 555PS owners here share your experience on that? Some say a power conditioner might solve the problem. Are you using any?

I am trying to do all the possible due D research before spending US$4k on this 555PS.

Thanks a lot in advance.

When comparing a new 555DR against my several years run-in non-DR 555 PS I preferred the latter. The DR was detailed but lacked warmth in upper-mid and HF lacked fine detail…but that was new.

After a few weeks it opened-out and improved - but to my hearing it took a good six to nine months to fully-eclipse in every way my old non-DR 555PS, so I prefer the DR version - it is vastly better in terms of detail and lower coloration and lower noise.


Thanks Charlie,

Can the two burndy connections be used for two separate devices simultaneously? Ndac and CDS3 for example?

Ptcm10, no the 555PS should be used to power only one device.


Thanks for that observation. I suspect that may explain the ocasional preference for non-DR over DR.


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A ‘hum issue’? It’s not common at all. And no - my 5555s don’t hum.
Using. Power conditionaer is an absolute no-go with Naim ot kills a sound.

Further - humming transformers (I guess this was your question) will not really be cured by a power conditioner.

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Hi PCTM10, yes, lots of 555PS transformer hum here too. It became really annoying. There is a thread on the old Naim Forum called “Suffering from those transformer hum blues?” which charts our journey to deal with it. We tried several expensive power conditioning devices which didn’t work.

However, an Airlink Transformers Balanced Power Supply hard wired into a dedicated radial supply for the hifi worked a treat and with no downsides that we could detect. It benefitted the supercap, NAP135s and 555PS as all were suffering from transformer hum. It cost about £550 at the time.

Note that this is for a UK installation. Electrical standards vary by country, so use a qualified electrician to guide you on how to do this.

Here’s a photo of our 5kVA BPS which powers the hifi to this day:

Hope this helps, BF

Hello Bluesfan,

Thanks for the info. I wonder if this issue is only specific to UK users or global? Can any non UK PS555 users confirm that please?

I asked the potential seller. He said he doesn’t hear it, but any potential sellers would say that for obvious reason. I could be overly skeptical on this one.

I would love to try the PS555 on my Ndac/CDS3/CDX2. That said, I am trying to do all the research I can on this known issue before I take real calculated risk.


It’s akin to saying that ALL Jaguars suffer from a steering wheel vibration. Just because a small sample of people that wrote a review, drove it on pot-holed B-roads… I’m sure that Jaguar know how to manafacture a car, so that it doesn’t vibrate…

I live in Poland and I can confirm that my two 555PS, my two SuperCaps DR and my HiCap do not buzz…

This is not a UK specific issue. The root cause of the humming is so called asymmetric mains, otherwise known as DC offset. In essence, it occurs when there are a lot of “dirty” power supplies in your area that inject noise back into the electrical supply, or poorly designed switch mode power supplies that draw more power from one half of the electrical waveform thereby creating a “dc offset”.

So, if you live an an area with a “clean” electrical supply, then your Naim transformer will not be affected.

If you live in an area with many poorly designed power supplies, then the same transformer will be at risk of humming. Highly efficient, toroidal transformers of the type that Naim specify make our Naim equipment perform at their best but are also vulnerable to this type of mains borne interference.

You just have to try it and see. If it’s a problem, then install a well designed “DC blocker” or a BPS as we have done. Then enjoy the music! Given that your ndac and CD player power supplies do not hum, then it is unlikely that the 555PS will either, as all are susceptible to the same mains borne interference.

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