Power supply Statement PS...

Batteries are not always the best solution. Some gains, some losses using this method. Better to have a design that doesn't need multiple power supply boxes in the first place 

Box count, ICs, service interval for the battery box. Inevitably, a Powerline charging the battery would make it sound better.

IIRC, Naim investigated battery supplies for the 24V DC pre-amps some years back and overall felt they under performed against a well regulated mains transformer fed supply.  

+1 on James N: I spoke to the developer of the Schaefer Emitter, which does use batteries (I think only for the preamp): He also said that batteries have their own problems (incl. noise?!) ... and converted me to normal ('on-line') PSUs.

S.

This falls very much into the "more than one way to skin a cat" category.

There are designs out there using batteries to deliver stable mains decoupled DC current. There are, designs that use really good internal shielding to minimise interference. There are designs that put the PS in a seperate box (Naim, many others). And they can all sound good.

What is clear as that where no regard for the importance of the PS and minimising its impact is given, then quality really suffers, no matter what the brand is. I would say that external PS with the DR technology and large caps is probably the best of both worlds. If someone has electrical engineering expertise and beleives otherwise then the likelihood is that there is more about Naim's design decisions than just the offboard PS that they will disagree with and maybe another direction is more suited.

On the other hand, if you disagree but buy Naim because you think it sounds good, then maybe consider that one of the reasons for this is because of the attention and method of PS design, not in spite of it.

Quite. It's all down to compromises, something any engineer has to do to meet performance, cost, time considerations. Where cost and time is less of an objective (ie Statement type products) then less compromises need to be made. It makes a lot of sense to seperate the mechanically and electrically noisy power supply from the sensitive components of a pre-amp but this is not always acheivable. The Statements are interesting in that the power supply is incorporated into the design which allows Naim complete control of the mechanical and electrical environment but with the real estate available to maximise isolation from the sensitive parts. Very nicely done. Given what they can do when let loose on a Statement amplifier project i look forward to what they can do with a digital source