When talking about 552. I understand it likes air around it. I have the possibility for the below. Which is likely to bring best improvements? I believe it is good to keep it away from digital when possible meaning option 1 is to prefer?
500 Head
552
Empty
NDS
500 Head
Empty
552
NDS
NDS has suspended sub-chassis and is a source and will IMO sound far better higher-up off the Fraim base level certainly.
When I ran a 552 - ND555 I found the 555 top, then a medium shelf from 552 under next down, then an empty self and base unit.
But if I also needed to fit-in a 500 head unit probably:
NDS (on medium)
552
500
Empty.
That should sound fastest with most detail as 500 head IMO is quicker-sounding off the lowest base-level.
But is needs a Medium level under the NDS to give the gap from 552 - well-worth it as the standard level is not enough but Medium is fine and words well. I home-demoes NDS this way before I eventually went for ND555 and run it with my 552 for many years before the S1 crept-in.
DB.
The battle off the top shelf is continuing. All boxes should be there it seems 
I think if people use Vinyl as a source - which is always on its own shelf for best performance - then 552 on top sounds best and that is where ‘best on top’ came from, as in that context, it is.
But I found many years ago after making the migration away from Vinyl first to CD (CD555) then to streaming (ND555) that the source always likes its own space around it beit Vinyl or digital.
I know people that nestle their digital source in between other boxes and say it is fine but never actually tried giving it the same space that they have for their turntable and know how putting that onto a heavy equipment-laden shelf hammers the timing and detail…
Well…I found it does exactly the same for a good digital source when you put it on its own shelf. It was impossible to un-hear that and although awkward and inconvenient for me room-spacewise, that is absolutely essential in my system and cannot be made-up for elsewhere I found. Once gone it is gone.
I found far better bass and timing, more air and fine-detail - just far lower invasive shrowd of cloying-noise removed. The bass details begin to form shapes and gain amplitude and dynamic structures that just collapsed into amorphous ‘bass’ many systems can have as normal.
Consider experimenting and you may uncover many capabilities you have latent in the system you have otherwise paid for but not realizing. 
…but it is a lot of system space so compromise is required to get what best works.
I’d add another stack of Fraim but my room cannot fit it so have to suffer only four stacks and not the more optimal five. 
DB.
Wow, I hadn’t even consider space around the boxes…
I currently have 2 stacks
Turn table
552 head
NDac
ND5XS2
Empty
Empty
552 power
555Dr
300 Dr
300 PSU
Shelf for the Turn table will be next
Then I can use the other shelves to space out the digital stack I guess…
One thing to also try to achieve is to have the Power Amp PS either in another stack or at least with some space from the next box. So in your sequence above use a medium shelf to space the 300 head unit from the 300PS. Otherwise it is probably still the best place to have it at bottom away from other stuff, but I found the sound opens-out with better timing when there is some more space to move that PS away from the head unit more.
DB.
Thanks DB… I’ll have a play and report back.
I’ve had mine for over 20 years and it still captivates me for several hours a night. A true treasure….
my current setup with 2 Fraim is :
Left Fraim:
NAS
ND555
552 head
Empty
300 Head
Right Fraim:
1st 555Dr
2nd 555Dr
552PS
Linear PS for switch/NAS
300PS
This way, amp and power supply are as far as possible from sources and pré
A suggestion: Try with the NAC552 head unit on top the left Fraim. In my experience the head unit doesn’t like anything Digital too close right above it. It’s most apparent with CD players, but also with other digital kit too such as a streamer.
How about digital like NDS beneath 552?
i’ll try…next time i’ll get the courage to move the Fraim’s for a cleaning sessions
Having the digital player above always seems to be worse, I have found.
I moved my stacks around this morning and I’m happy with result.
The config is (top to bottom / standard shelving)
Left side
552 PSU
555DR
300 head unit
Space
300DR PSU
Right side
552 head unit
Space
nDac
Space
ND5XS2
As @Darkebear said it seems to have opened things up more. While I was happy with the improvements the 552 brings over the 282 I did feel as though the sound stage was slightly limited. Not by much, but there was a difference. Moving the 300PSU away from the head unit seems to have rectified that… happy days.
Have you dressed the Snaic close to the 552 Burndy ?
they’re as far apart as the connections allow…
Hello, Maybe move nDAC down one and 300 head under 552, with a space between NDAC and ND5XS.
They should be as close together as possible without touching.
I always want to ask what’s the technical reason behind this.
