2x555DR vs. 1x555DR on a ND555

I already had the twin power supplies on my NDS, which had made a noticeable difference, so when the ND555 came along, itself a major game changer over the NDS, I simply carried on, and haven’t felt the need to try it with a single supply.

ND555 + twin 555PS, just stunning, across all inputs… nice one, Naim.

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Absolutely! Even through a more modest amplification, the ND555 is able shine (as described in the HiFi+ review).

My own experience of the ND555 with an additional 555PS was an extremely pleasant surprise.

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Thomas, having just heard what a power regulator can do (unfortunately) at my home, I have now opened the door to another hi-fi purchase. The difference is quite literally astounding - especially considering that I already have a standalone circuit for the stereo… so my question to you is what research did you do around this and what was your conclusion? Appreciate any pointers, may accelerate my evaluation process.
Many thanks, and a Merry Xmas to all
Robbo

I’m about to splash out on a 2nd 555DR for my ND555. I have a rack with just power supplies, from top to bottom: 555DR, SC DR, HCDR (for Headline), Spare (used to hold my FCXS which I’ve sold) 300PS. I think I have read somewhere that the newer 555DR should feed the analogue and be uppermost, so plan: New 555DR feeding analogue, Older 555DR feeding Digital, HCDR, SC DR, 300PS. I think both the Burndies and the SuperLumina SC to 300 will cover all shelf positions. Any advice to the contrary?

Thats how i have mine, the newer 555 dr is on top, more because i did not want to take it all apart. Anyhow, it will sound just fantastic…enjoy your christmas and future music.

I am into Ansuz Acoustics powerdistribution and boy THE way also my switch is coming from them. THE right distribution and power cables make a significant difference. I have Naim power from Naim devices to Powerdistributor but also an advanced cable from distributor to special wall outlet. Just give it a try and you will be pleased…

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What I heard was a MASSIVE transformer (50kg worth) plugged into the power supply
pre the system, at the mains board. Apparently this pushes a stable power supply through to the naim PS boxes ensuring they can concentrate on the stuff they do best. I am no expert on electrics, but I can say that the effect was jaw-dropping. Interestingly we tested the incoming power, and it is was very stable and very close to 230V, yet plugging in this transformer made everything bigger - soundstage, thunderous yet super-tight and tuneful bass (blind testing I would have sworn we’d added a sub), top end more open and music filling the room, and removing in-room resonances (no idea why that would be).
The impact was greater than the second 555 PS, and is probably half the price. May be something to think about for any of you thinking about the second PS!

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I currently use an ND555 through a Supernait 3 with HiCap. I find it a sublime combination. As the dealer went up through the streamer range I was pretty convinced that somewhere around the XDX2/XPS level that improvements to the sound just wouldn’t come through the amplification. Well I was wrong. We never tried two power supplies on the ND555 though.

good evening to all and best wishes. i searched the connection diagrams for 2x555 ps on a nd555 but i could not find anything. would you explain to me how they connect please?

Oh, and the added advantage of course is that the whole system benefits, not just the digital source.

hi Robbo. Thanks for the photo. But the 2 burndys are connected to 2 different 555ps? The standard connection scheme foresees that the 2 burndys are connected to 1 a 555ps, respectively a burdy on soket 1 and a burndy on soket 2. in the case of two 555ps?

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Quite simply one burndy is connected between socket 1 on the 555 and socket 1 on the first 555PS and the other burndy connects between socket 2 on the 555 and socket 2 of the second 555PS. One 555PS then supplies the analogue power and the other 555PS supplies the digital power whereas with only one 555PS in use that has to supply both the digital and analogue thus the two burndies run between the 555 and the 555PS with both sockets on the single 555PS being used.

many thanks, now everything is clear to me. in this way in practice it is as if you are providing all the power of a 555 ps on the digital and all the power of a 555 on the analog, right?

Is the full 555ps being used when u have 2 555ps’s?
Or just 1/2 of each PS?

Clearly it’s a bit more than 1/2 of each since some elements are shared, but because I too wondered about this, I swapped them over last time I had to break the system down. I can’t say I heard any difference though, but then it takes a while to dismantle the Fraim , dust, polish and reassemble, so it’s not really a direct comparison before and after.

I believe DB gave a full explanation of what is used in the 555PS when used in combination with a single head unit, but as you say it’s more than half in each supply.

From the ND555 White Paper

Next stage for Naim could be to split the nd555 into 2 separate boxes. Say, the nd555 anal. & nd556 dac. With a dc1 to join the 2 boxes, each fed from a 555ps?

Approx £33,000+ maybe?