Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Power supply upgrade

More great R&D from you Nick...many thanks.

Best regards

George

As always Nick, nice work!!

This is really intriguing. Anniversary series performance for M processors!

i'll try and snap a photo of the PS I haven't dared to put in but it's probably not anniversary.. erm I mean LPS.

Guys - are there any pics around of the Anniversary PSU? I'm curious to know if it is in fact a fully linear installation, or if it's a SMPS with a decent capacitor bank and a basic pre-regulator...

Nick - Could you PM please with all available details for the removed SMPS - voltages, current ratings, OEM part number etc if available - I have a plan...

Here's some information from elsewhere in the thread:
http://octopart.com/ecm40ut31-xp+power-995892
http://xppower.com/orderPriceList2.php?seriesid=100224&lang=EN
http://xppower.com/pdfs/LF_ECM40-100.pdf

Yesterday I had my amps go into protection mode again, after a short very loud burst of noise.

Although this does not happen often, am I starting to believe this must be related to the power supply (7 years old G68). I'll see how it goes. This could be a good option.

Hello,

I had exactly the same problem with my G68. It was a power supply failure. I replaced it, and since, no more problems.

There seem to be two motivations for a power supply modification.

Some people are fed up with the unreliability of the SMPS - predominantly in the G-series, I think? Meridian have got something wrong, and a clean sheet design may be a good way to get a reliable supply. I don't think I've ever had any PSU fail on me, and its not something I lose sleep over. The ECM40UT31 is so cheap and readily available as to be disposable.

However, if I'd had a PSU fault that actually damaged the controller, I expect I'd have a very different attitude. I'd probably want to find a more reliable solution - as long as it didn't add more problems than it solved.

My motivation has been quite different - it's purely sound quality; I've been convinced for some time that SMPS are bad. And bad for digital circuits as well - not just analogue circuits. When a little research showed how commonplace, and how bad, the stock SMPS are, it made the effort and the risks seems worthwhile. So if it's possible to fit an LPS for less than Meridian charge for an SMPS - and get better SQ and better reliability into the bargain - why not?

Of course, I can't prove that LPS are more reliable than SMPS, but they really are pretty simple, and the common designs have been around for a LONG time. It's not proof, but I think it's a pretty good indicator of a mature design that's had all the common pitfalls developed out. The better supplies also have lots of nice-to-haves, like adjustable outputs, over-voltage protection, remote sensing, battleship engineering, etc. In other words, the sort of things that help to look after the equipment, and not just protect the power supply itself.

Nick

I've been giving this a bit more thought, and looking at the FG 905 heat-sink, it's mounted to the PCB by a couple a screws from underneath, that screw into a transverse ridged slot in the base of the heat sink (rather like Meridian use a lot on the 800/861). If you look at the picture, you can see there's another slot in the top. So it might make sense to fit the 905 supply up-side-down, by screwing the heatsink itself into the base of the controller. By adding a heatsink gasket or paste, the equipment chassis will help to cool the supply. Mounting is also simpler, as the mounting holes don't have to be in exactly the right place (which makes conventional installation tricky if you don't have a specially made drill jig). The end result won't be as pretty, but I like this idea.

Nick

If you're looking to an external supply, you could put a multipin connector on one of the blanking cards; but the tradeoff is that cable have to be longer, which is never good.

I wonder what the best option is for the G series, as space is more limited.

Do we have a clear 'winner' for direct (almost) replacement SMPS or G series compatable PSU?

Having just stripped my G68, it's interesting to see that the 800 series casework looks less solid than the G series!

Another great post nick!

Could you be talked into building a supply for me - or guiding me through the installation?

Which supply should I buy for my G68adv ?

I tried to reply yesterday, but my PC had other ideas.

Having used equipment with external power supplies, I think being able to plug local mains directly into a single unit is very convenient.

The ideal power supply has zero output impedance, and the best super regulators get that down to a few milliohms. ANY sort of cable and connector is going to affect that, and hence degrade the load regulation - the supply's output voltage will be modulated by the load. Using separate load sensing lines is a solution if you're happy to make the connector more complicated, but even Belleson point out that such lines risk adding noise and interference.

For the G61, there really is only one option - the FG Elektronik NMC 905. That may work with the G series players as well, but I'd like to try it out first.

Pretty much anything will work in the G68, from the FG 905 to the Condor 105. The bigger the better, as far as I'm concerned.

Yes, the 800/861 is nothing like as solid inside as it appears outside. Its not Meridian's way, but there's got to be so much scope for anti-microphony measures.....