Antoine's system

[Antoine]

Thanks guys!

Regarding the Sonore PS (terribly overpriced IMHO for a 7V/2A single rail PSU!!), the review did mention it was used but the price hadn't been disclosed until yesterday. I do agree this could have been made more clear although I don't think it was done deliberately. Chris mentioned in the review the power supply stuff will be discussed in part 2 of the review. Also both Barrows and Jesus R have said on CA the PSU was going to be expensive. Based on one of Barrows remarks who said something like the both would be around $2000, I estimated it was going to cost around $1400 to 1500, well they added another $1000 or so! Indeed it looks to be 120V/60Hz only so it's not even an option for us. I wish them luck with it and am sure the one I'm getting will be much better.

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I have to be honest and say that this power supply stuff is anything but easy. It's hard to know what to look for and even if you do, manufacturers of commercial off the shelf supplies don't provide detailed specs or measurements.

This is a helpful (in explaining why it's a so difficult) post by John Swenson on the matter:

http://www.computeraudiophile.com/f26-so...post533885

On the power supply side of things, I can tell you the technical details of what is most important, but it won't do anybody any good because nobody tests supplies for this. there is no agreement on how to run the tests, there is NO off the shelf test equipment for this, anybody who does this (and very few are ever done) has to build there own test equipment from scratch.

It is theoretically possible somebody could build the appropriate test equipment and test a whole bunch of supplies and publish it, but they would have to get all the supplies and spend a lot of time doing it. It would be a huge project, take a large amount of time and cost a lot of money. I'm not sure who is going to pay for that, the project would have to pay someone a lot of money to take it on.

So for now there is NO WAY to technically select the best supplies, the measurements simply have not been done.

That leaves people listening to things and subjectively figuring out which sounds the best.

If you really are interested in the details, here is what is needed.

For computer type digital equipment the noise coming from the supply is really not that important. Particularly for the microRendu which has ultra low noise regulators with extremely high noise rejection.

The really important part is how the supply responds to transient loads. All digital circuits do not present a constant load to the PS, the load current varies all over the place. This changing load is not slowly changing, it makes large current changes very quickly, the supply has to deal with this and keep the voltage constant even though the load is changing rapidly.

These "transient load events" can be very short duration, medium duration or long duration. The short duration events can be handled by small capacitors near the load. The caps have to be physically small in order to keep the inductance down. But physically small caps don't hold much charge, they have to be re-charged by a fast acting regulator. This part of the system is built into the microRendu board.

These regulators have to be fed by a larger cap that can handle the medium duration events. This is also on the board.

But THOSE caps have to be fed by the external power supply. It has to be fast enough to quickly recharge the first level caps. In addition it has to KEEP them charged. What happens is that the supplies that are fast enough to properly deal with the load don't have enough capacity in THIER caps to keep it up for long. When a long term transient happens the small caps handle the first little bit of it, the caps feeding the regulators take over and keep it going, the caps in the supply take over and keep on feeding them, but the AC line part doesn't react fast enough and the output caps sag before the AC part can recharge them.

This is the big challenge of power supplies for digital circuits. They need to have large capacitors, but this usually means a slow supply. This requirement leads to strange things like needing a 6A supply to properly handle a 1 A load. If you just design the supply as 1A the transformer and diodes will have too high an impedance to react fast enough, and the caps will be too small.

There are two different ways this can be measured. The most obvious is to build an adjustable load that can be programmed for different transient loads (different changes in current and different durations of the change) and run a whole bunch of these and see what the supply does. This is a lot of data that has to be looked at. One big advantage is it shows exactly what you are looking for, how the supply responds to transient loads.

The other approach is an impedance VS frequency plot. This is one test that shows everything, it is very easy to compare between supplies, but it is not so obvious how to convert this to what you really want which is the transient response. Once you learn how to interpret the results it's actually easier to use, but it takes some effort to learn what it means. Neither of these is a nice single number people like to have to compare things, there just is not such a simple thing in this space.

John S.

So how to choose the right supply? I wouldn't dare to say I know how! I think it's a bit like buying an amplifier, it needs to fit the system and taste of the owner. Personally I have been reading, reading and reading a lot and piecing the information together led me to my short list. The choice I've made to include Paul Hynes on that list is also based on what I've read over the years I've been in this hobby. His supplies are simply SOTA and fit almost any audiophile purpose so this, John Swenson's "approval" and the great deal I found made it easier for me to choose it. The SR7EHD-MR4 I'm getting is WAY overspecced for this purpose. It has one high current rail that can put out a sustained 10A @ 12V and current peaks up to 50A, then there's three 'low current' rails that can also put out 2-3A each. However bigger, though 'over the top, in this case is better. It's a bit like the sports car vs. familiy car analogy.

Initially I contacted Paul Hynes for a SR3 model. Then Octaviars mentioned the DIY modules which I though could be a good idea as well and later I saw this ready built 'surplus' SR7 from his own system. I mentioned it to him in an email explaining my wishes and Paul offered it could be modified for a moderate fee. Wouldn't I have stumbled on the offer I still wouldn't have made my choice but would have likely gone for a single rail SR3 or more expensive dual rail SR5 or would have waited for the Uptone Mystery PSU or some other solution people like.

I'll copy paste some information about the Hynes supplies in the next post.

Here's some reviews that also give some general information about PH, the business and it's products:
http://hifipig.com/paul-hynes-sr3-power-supply/
http://hifipig.com/paul-hynes-ph5-power-supply/
http://www.adventuresinhifiaudio.com/24/...dog-audio/