Power Supplies - Thoughts

Posted by: Stuart M on 26 August 2002

One of the biggest improvements to make to Naim equipment is to add a better power supply. The supercap was originally for the 52 but improvements using a supercap on a 102, 82, Prefix etc are well documented.

With the 552 the power supply is included and not compatible with old equipment. This was the case when the 52 was first launched with it's own power supply that later became the supercap.

Although at present I've other things I want to upgrade first when I reach the stage to upgrade the pre amp my first plans would be to supercap the 102, then the 52 would be the next. After this the cost to go 552 would be large. If a 552 style PS was available for older equipment then a 552 would be a much easier financial jump.

Given the Naim history of redoing power supplies after initial release e.g for CDS, 52 into more general power supplies would this be possible, in theory, for the 552 PS, as it's split rail, to in future, with some redesign, to be used on old style equipment? Or are we talking a complete break.
Posted on: 26 August 2002 by JohanR
I think. But there will probably be new cheaper pre amps that's using the "new" technology, something like a 582, coming along. And a double ended HiCap (D-Cap?).

Interesting, this complete change of circuit topology. Everybody else has used double ended designs for decades. And now, when single endedenes has become popular in the Round Earth world (Conrad Johnson Art xx, Nelson Pass and all the singel ended tube designs), Naim goes double ended!

JohanR
Posted on: 27 August 2002 by Andrew L. Weekes
If you read the marketing info on the Naim site there's nothing there to imply that the 552's power supply is radically different or better than the existing designs. There may well be some cleverness that is 'radical', but Naim have not given this information away, not surprisingly.

It produces + and - supplies, but uses off-the-shelf power regulators as with older designs, so big gains in performance, from these parts alone, are highly unlikely.

The new circuit topology is most likely where the gains are to be had - less current flow into signal earths (as stated) and better PSU rejection of the basic circuitry.

Andy.
Posted on: 27 August 2002 by rohit
one shouln't expect to see new head units (102.5, 82.5, 52.5 , 250.5 etc.) that require the new split-rail supplies (HiCap2, SuperCap2 at appropriate price points)....to be inter-changeable with the curent line-up.

quote:
Everybody else has used double ended designs for decades. And now, when single endedenes has become popular...Naim goes double ended!



in the new models, it is the DC supply rails (more so in the NACs) that are balanced and not the signal which is still single-ended into the NAC and out-into the NAP. i'm guessing...this will be most beneficial when used alongside (new) boxes where the common rail (marked -ve) is not tied to signal ground up/down the chain.
it remains to be seen how the new models will deal with local/remote regulation and if the mid-line NAPs will have their outputs lifted off signal ground as well.
fwiw, the split-rail isn't be as radical as we think. the mods to rail design from CDS1 to CDS2 already point to it.
Posted on: 28 August 2002 by JohanR
Rohit, if I understand you correctly, the 552 works more like a NAP 500. The NAP 500 is two "normal" amps that are bridged as a part of the design (I think). The 552 should then be considered as two singleended, classic Naim pre amps that are bridged together?

Or?

JohanR
Posted on: 28 August 2002 by rohit
i do not know, but can only speculate the specifics of how the 0v point within the 552 circuit can see the -ve signal pin and not supply ground.