ND555 + 2 x 555PSDR

Streaming Audio
75

Is that why it didn’t sound right for the period i did have it working?

76

It can easy be that.
Naim have a protection circuit in their PS that ensures both positive and negative supply voltages rise in-track on switch-on and if not will trigger the protection and shut the supply - but since you are blowing a fuse it could be instead a Cap has gone leaky and drawing more current on switch-on that expected - that will blow a fuse.

But that is from experience building Amps years ago and it is just speculation.
If the regulation if off though it will have a lot more ripple-current and noise on the supply for the final PCB-side regulators to try to remove and it will definitely sound worse than it should.

It should be easy to spot and fix.

DB.

77

My 500 is fully updated and serviced but the transformer is the original circa 2002… and it is a grumbly beast…I suspect one day it will go into short circuit…its a concern I am thinking of sending back to have a new transformer. Apprently according to Steve Sells … the transformer specs have improved steadily over the years…and they are allot quieter now.

78

I know this has been covered before but I can’t find the relevant thread.

Hypothetically speaking, if I were to mix DR and non-DR versions of the PS555 power supplies on my ND555, which would power the digital side and which would power the analogue side for optimal results.

All hypothetically speaking you understand.

79

Probably the DR one onto the Digital side.

DB.

2 Likes
80

@NigelB (Hypothetically speaking) I read the opposite to @Darkebear, stating that if using a DR and non-DR, ‘DR’ wouldn’t add anything to the digital side.

I’ll link if I can find it.

Found it!

Try both would seem wise.

G

1 Like
81

Thanks Graeme. I have just read through the thread you pointed me to and the consensus is that, when mixing DR and non-DR, it is the non-DR PS555 that goes on the digital side, as the DR seems to have limited impact there. This is the key finding for me, in that I would not be losing out by adding a non-DR to my existing DR version, instead of 2 x DR versions.

However these comments about mixing DR and non-DR PS555s are when powering a CD555, but I assume the same holds true when powering a ND555.

82

Hi all,

I am considering a 2nd 555PS on my streamer. Tried to understand how they would exactly be connected but couldn’t find anyting (not the manual, nor the connection guide unless I overlooked). Can anyone explain: is it just one outpu of each psu going each to either the anolgue or digital input in the ND555?

Iver

83

This helped me move from ‘hypothetical’ to ‘life’s too short’.

G

84

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G

85

I saw that one @GraemeH ; thanks. My question is rather on the PSU side. What goes out from which connector there?
Iver

86

With 2 x 555PS you use one Burndy out from each PS. Digital 1 out from one supply and Digital 2 out from the other supply.

G

1 Like
87

You’re screwed.

5 Likes
88

Ahh, that what I wanted to know
Thank you so much @GraemeH

1 Like
89

Thanks (I think) for pointing me to this thread.

2 Likes
90

My 500 was dr’d 5 years ago.
Is the transformer replaced when this upgrade is done?
Sorry to divert from the thread
David

91

No the power supply doesn’t even get looked at. With amps all the dr’ing is on the amplifier side and not power supply.
You don’t even send the 500 power supply off in the dr upgrade unless you are getting it serviced at the same time and paying extra.

92

Does anyone know what was replaced in a 555PS when it got DR’d?

Thanks

G

93

No…but I can see mine having to go back…mine was done 4yrs ago…she is extremly grumbly… I am going to update my mains supply to see if that helps… I had a full service as well…but that is only the caps and some resistors…

94

All my othere units are vertually silent…