Quote Originally Posted by r100 View Post
there are some nice looking ones on the eBay, maybe like this one ?
http://www.ebay.com/itm/Hifi-linear-...item20f80f7928
I'd be very careful using any 'off the shelf' linear PSU unless you know *exactly* what the Pi's electrical requirements are, not only in terms of getting it to function, but in achieving a worthwhile improvement over the supplied SMPS unit.

As I reported earlier, our resident PSU expert (Paul Hynes) is currently designing such a linear PSU for me, for the Pi, and have been exchanging some dialogue with him on the matter. As a point of note, for those interested and able to understand what he's written, this is some of what he had to say on the subject:

Quote Originally Posted by Paul Hynes
The Pi boards I have here both have three low cost regulator chips for power distribution. It should be possible to replace these with my high performance regulators once I have the set-up running.
Then after looking at the circuit of latest Pi model, he said this:

Quote Originally Posted by Paul Hynes
The latest Pi has a completely different on board regulation system to the ones I have here using switch mode voltage regulation to provide the lower voltage rails. I will have to do some investigation with this, as I have no clue how much current is required for each rail. The current rating of the regulators will dictate the physical requirements of this upgrade so I have a little R&D to do to deal with this solution. Also the high speed shunt regulators I use for digital circuitry cannot regulate down to 1.8v for one of the rails so I will have to develop a circuit that can provide the 1.8v at the required performance level.
He has since bought the latest Pi and an IQ-Audio DAC+, in order to facilitate his experiments, so I am awaiting the results of what he comes up with.

The conclusion I reached from what he wrote, however, is that if you want to do the job right, and obtain optimal results (which is all I'd ever be interested in), you *must* have an intrinsic understanding of what makes the Pi (and IQ-Audio DAC) 'tick', so to speak, and simply buying an 'off the shelf' linear PSU from ebay is unlikely to produce the desired effect.

Marco.