Not quite - the acrylic block between the top and bottom enclosures stops eddy currents in the case flowing around the whole enclosure and inducing noise into the sensitive top enclosure circuitry. It’s not acting as a screen, just as an insulator between the two sections. The best thing you can do with your pre-amp is ensure good separation between that and mains powered components, especially the big power supplies. One of the reasons the brain / brawn stack structure is popular.
To a degree, but the Reference sized boxes don’t have the real estate (and lack of budgetary constraints) the Statement design team had to play with to minimise interaction. I doubt we’ll see a one box 500 integrated - I’d expect a 2 boxer, with power supply in one box and the amplifier section in the other if this was ever to happen…
Naim’s design for the Statement rather cunningly has the transformer mounted on its edge, so that the transformer’s main electromagnetic field radiates sideways, rather than vertically.
To the best of my knowledge, all other Naim transformers are mounted on their front (or back!), so their electromagnetic fields radiate vertically. This is one reason why increasing vertical spacing or multiple stacks help to reduce the noise in all other Naim systems. I suspect that the Statement amplifiers benefit from greater horizontal spacing between adjacent boxes.
So looking at the standard PSU’ radiating vertically, would a bottom shelf be good for a NAC or source?
I suppose it would also be interesting to know what gap you need to leave above a PSU. Naim seem to have gone to great lengths developing a perfect Fraim so maybe they have some more information on PSU’s that would help set up.
The vertical electromagnetic radiation from Naim’s transformers is one reason why the use of two stacks works so well - one for “brain” components which are low voltage inside, the other for “brawn” components which have high voltage transformers in them. The separation into brain & brawn instils more karma into the sensitive, low voltage components such as phono stages, pre-amplifiers and digital source components that use an external power supply. And you can never have too much Karma in your system unless you play lots of thrash metal.
By all accounts, Naim pre-amps seem to like having nothing between them and the Lord above, so top of the stack is the default location for a pre-amp whenever possible.
Some owners, notably @Darkebear, have gone to some length in order to optimise the spacing and positioning of all Naim boxes and have shared their findings on a number of forum threads.
As to the optimum spacing for traditional Naim boxes, the more the better seems to be the case, within the limits of interconnect cable lengths.
Curiously, when viewed from the front, Brain on left with Brawn on right sounded somewhat calmer and better to these cloth ears than Brain on right and Brawn on left.
The only explanation I can think of to explain this phenomenon is that the transformers are even further away from the Brain components when Brain is on the left. It cannot be anything to do with mechanical transformer vibration, as there is equivalent mechanical isolation between Brain & Brawn in both configurations.
I found that I was getting diminishing returns on upgrades - until I discovered that the big transformer items need more space for their associated equipment to really open-out and deliver what they are innately capable of.
With the S1 Pre - which I consider one of the largest upgrades in context of Active system I have made so far - I initially found it, upon replacing the 552 Pre, to be so overpowering in deep bass and sub-bass that I was getting headaches with the very low bass, until I discovered how to fix it.
The fix was to give my three NAP500 PS boxes room apart from each other - the PS boxes being apart was in fact more important than almost anything else, but not something many will encounter as a problem unless running Active and having more than one Amp.
The over-heavy oppressive sound just vanished to be replaced by superb timed bow-bass and everything so much clearer - it is well worth doing. It was worth the extra Fraim Std level spacer between my BMR 500 PS and the Bass 500 PS and the medium Fraim swap-out to keep the two Bass 500 PS also apart. If I had more space I would put a bit more space, but I reached the critical ‘it works’ threshold within the limits of room space, so I’m good with the present solution.
But if people have not tried more space - especially from the large transformer containing Power Amp boxes then they are probably missing a lot of their system potential IMO.
I have two racks assigned for all boxes downstream of the S1 Pre:
First rack to right of Pre is all the PS boxes(bottom up):
base level (500PS) - Med Level (500PS) - Std Level (empty) - Std Level (500PS) - Std Level (supercap for SNAXO).
the that all feeds the Power Amp Box Rack - with SNAXO at top:
Base level (empty) - Std Level (500) - Med Level (500) - Med Level (500) - Tall Level (SNAXO)
The Statement is on floor feeding these and is fed in turn from ‘source item(s)’ to the left - the ND555 on its own table alone (2x Med Levels one empty) and the 2x 555PS on a ‘source’ PS stack - with my Melco on the top shelf (555PS on base - Med with second 555PS - Std with Melco.
…it would sound even better with Supercap on a Medium Level - but then the lead to the S1 does not reach!