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

It's time for an update, and I decided to order an R3 Power 00-3516 linear supply from Farnell, who delivered next day, from Belgium I think. Good service, and I also got the optional chassis cover. I got the last unit, sorry guys, but there are PLENTY of other options. This unit is much the same as all the supplies highlighted in blue in the table above. You can see it sitting on the base panel in the top, right-hand corner.

http://uk.farnell.com/r3-power/00-3516/psu-linear-regulated-3-output/dp/1302373
http://www.farnell.com/datasheets/49895.pdf

So I'm now working to install this supply in my 861V2. I'm going very cautiously, and decided to completely strip the processor - I didn't want to risk getting any dirt or swarf into any of the electronics. The obvious location for the supply also meant drilling holes close to the corners where I couldn't get the drill in. Fortunately the main panels are ally, and easy to drill.



Unlike my V4, the V2 had the existing PSU filter board on the side panel, and I decided to move it to the base, so the wire runs could be shorter. On my V2, the PSU ballast resistor had unstuck itself from the base and overheated the wiring. The power resistor was fine, but I had to rewire it.

I also wanted to remove the front panel for safety, but the small allen screws had been rounded out, so I had to drill them out and replace them. I did try to avoid making any stupid mistakes, but there were a few lessons learned which I'll share a bit later. I'm quite busy at the moment though. Watch this space, its getting exciting.

Nick

It's coming together, though not without a few pitfalls. I was looking forwards to taking what is the 861 kit of parts, and simply re-assembling back to something that I knew was going to work. It's not a difficult mod, but getting a new power supply to fit in with that ideal wasn't so easy.

I bolted the PSU chassis into new holes in the processor baseplate. I mounted the filter board alongside, with the ballast resistor clipped to the PSU chassis. I soldered the existing power lead to the transformer, and replaced the DC leads and earth lead.

That was it, really. I checked the continuity and isolation of the DC lines and earth, then fired-up the PSU with no load to check the voltages were as expected. I repeated that with the filter board connected, then finished the re-assembly. That sounds simple, but I did learn a few lessons along the way that I thought I'd share by way of random, rambling guidance for any fools following in my footsteps.

Don�t unscrew the U-shaped perimeter trim at the rear of the case.
Don�t unscrew the transverse extrusion bars to remove the base or the lid.
The front and bottom panels are bent from one sheet of metal.
The top and bottom panels fit into slots in the extruded bars.
There are lots of self-tapping screws that are easy to strip.
The connections to the grounding stud by the power supply card are awkward.
Avoid removing the card rails � they�re fiddly to replace.
Consider whether the parts can be assembled in any order.
Note which way round the display cable & its connectors are installed (they�re not polarised)
The backplane can be removed on its own.
Rigid power supply mountings couple transformer vibration to the chassis.
Use spring + plain washers with every nut, bolt & screw.
Don�t use over-size cable � it's difficult to fit and difficult to solder.
The +5V DC output can use a single line instead of two.
Keep the 0V return lines separate � one for 5V, one for +/-12V.
DC outputs should be kept isolated both from each-other, and from the chassis.
+/- 12V outputs are usually adjustable � check the pre-set value.
The 5V output often has adjustable over-volt or over-current protection.
The power supply must have a good earth connection to the chassis and the mains.
The power supply must be fused per manufacturer�s installation instructions.
The power supply is switched on & off by the switch on the rear, not by the remote.
Get the right tools.
Get a static strap.
Get a good light.
Good luck.





At this point I have to admit that I'm starting to get nervous, as the 800/861 only work at all because they were developed around an SMPS. If they'd been designed around a linear supply, the development would surely have taken a slightly different course. How do I know, for example, that I won't suffer from a mains-related hum on the analogue outputs, that Meridian would never had had to worry about when using an SMPS? How do I know that everything will start-up in the right sequence? How do I know that something won't oscillate? Or a hundred other things that I haven't thought of?

Nick

Your candour does you credit, and you've already provided a huge amount of learning for anyone who is contemplating a PSU transplant. I know I won't be the only one wishing you best of luck with this...great work, and I look forward to the next installments!

Cheers

George

Nick,

Lot of work and thanks for sharing it.
Before you continue you should turn the PSU so that the opening does not face to the 861 electronic boards.

Why don't you use the sense lines?

Robert

Now this was the nerve-wracking bit. I'd had such a difficult experience with my Sony that when the time came to plug-in and fire up, I stood well back and cringed, half expecting a sudden loud noise, a lot of light and a nasty smell.

Instead, what happened was that the 861 started-up normally, resumed its previous set-up, and started playing music.

Of course, that's what should have happened all along, but I wouldn't have put money on it somehow. To say I'm relieved is an understatement. And now to the interesting bit - what does it sound like? Is it worse than before? Does it sound the same? Has the LPS made it sound any better? How does it compare with the V4?

I wonder, for a moment, what we would all like the answer to be?
1) Its an interesting endeavour, but there's no noticeable benefit, so what we have may in fact be as good as it gets?
2) Or there's some improvement in some areas, but a few downsides as well, so it its only worth it for fanatics?
3) Or...its a runaway success; can't believe what we've been missing; and why didn't Meridian do it before?

I have to say that I'm very much looking forwards to answering a few questions (and enjoying a well-earned beer or two, if I say so myself).

Nick

Apart from engineering prowess, you also run a very effective teaser campaign!

Cheers

George

It's me that's been on tenterhooks, I can assure you. I have quite a bit of time, effort, money and expectation tied-up in this. It's been played out in near real time, and the ending still might not be good.

I'm listening now, and it has been useful to have the v4 to compare with. Back in post 148804 I described the difference between the stock v2 & v4. I thought then (as I had before) that the v4 was somewhat better, not in a very immediate or obvious way, but in important and quite fundamental ways. Having had several audio processors, I thought the G68, 861v2 and the v4 were successive high-water marks for me. Though the latter was really bought for the MRC & MHR capability, I thought it was a useful step forwards as well. If the modified v2 could sound as good as the v4, I thought that would be a worthwhile achievement.

Now I'll cut to the chase. To me, the addition of the LPS didn't just take the v2 up the level of the v4 - it took it well beyond that. It immediately sounded better, not after lengthy listening, not after detailed A-B comparisons, not with some music and not other, it sounded better straight away. There's a significant improvement in clarity, resolution, soundstaging, dynamics, transparency, musicality - almost everything. The best thing is that its still recognisably Meridian, in that it sounds coherent, organised and balanced. There's no false emphasis in some areas where other manufacturers score a few points at the expense of others. It's exciting when its supposed to be exciting, and relaxing when it should be relaxing.

The best thing seems to be the way music rises out of an inky black background - there's no fog or hash or muddle. The detail was sparkling, but sounded liquid rather than etched. It also has that rare quality of being able to slow down time, then shock you out of your skin when you don't expect it. There's no plodding to a predictable beat, or imposing a particular style, pace, or presentation to the music. These are all qualities that Meridian processors already have (the 500- and 800- anyway), but more fully developed here

To put some perspective on this, the improvement of the v2 LPS over the v4 was at least twice as great as the v4 over the stock v2. Perhaps it was three times as great - I can't decide yet. It was certainly a significant and worthwhile difference, rather than a subtle, fleeting or marginal improvement. I'm tempted to say that its like going from SD to HD audio, if that's not over-stating it too much. It could be that an 861v2 LPS on 16-bit audio sounds as good as an 861v4 + HD621 on 24-bit audio. I'm a little unsure at the moment, but the improvement is along those lines, where you get the benefit in refinement and naturalness, rather than having detail thrust at you.

I've got some more listening to do, but so far it's definitely a (3) on the scale in my last post - can't believe no-one's done it before. So I'm very relieved and very pleased right now.

Nick

Wow. Great work. Now you have to mod the v4 and compare it to the v6

Thanks for sharing your experiment and opinion-results Nick.
They are in line with what I'll expect from such a mod (all new PS replacing a cheap SMPS one) after my own experiences with power supplies in audio gear (DACs and preamps in particular).
Why Meridian stopped using good (even simple like on 5-series) linear PS on the G and 8 series is beyond me but this has been already discussed.
Now I hate you because I am out of excuses to do something myself on my v4...

Nick, Very well presented

Regards I

So when are you going to start offering a modding service??

Duncan

Well Nick, you have done it now.

Based on M's response to HitchHikers experimenting with apodising work-arounds, I can predict that all future M components will be factory sealed and you will need an encypted key and thumbprint identification to open the box.

Only Meridian knows what is good for you.

Well done WellwynNick!

George #3

PS The orientation of the PS, as pointed out, can be very important. I would be inclined as a first experiment to place the PS outside the 861 and see if you hear any difference.