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

Maybe its something Gary Murrell could offer

Or Russ Andrews

Duncan

hehe

Impressive piece of work, your efforts are much appreciated. While I'm usually an advocate of the 'if it isn't broke, don't try and fix it' philosophy, it has got me wondering whether or not a linear PS can be persuaded to fit into a G68 case.

I�m not sure I want to go down the same road as Gary Murrell, though I don't mind doing a few mods for other people.

Although the sound quality is pretty much all I hoped it would be, there are a few notes of caution.

I didn�t really get to hear the impact on bass performance. It could be that the v4 carried a bit more weight than the v2 LPS, but then it could be that it was just thudding more - I�m not sure yet. I was listening with some Final electrostatics, and I�ll reserve judgment until I�ve tried some speakers that can, how shall we say ... dig a little deeper?

Linear supplies do have a couple of their own issues � heat and noise. They generate perhaps double the heat for the same output. I think the supplies I found are pretty robust, but there may be an issue with ventilation. I�ve only run the v2 LPS for a few hours at a time, after which the top was warm, but not hot. What it would be like with continuous operation, I�m not sure, and I don�t know if there�s any impact on safety or reliability.

The other issue is noise, and the transformer hums where the SMPS does not. All transformers hum at 50 or 60Hz, and I found this with my modified Sony as well. There are some straightforward measures to deal with that, though they do tend to conflict with the need to dissipate the extra heat.

Those qualifications aside, this has been one of my most successful and worthwhile endeavours ever, and I can�t wait to mod the v4 � sorry � that�s MY 861v4 I�m talking about, not Meridian�s 861v4!

Nick

Unusual: you need to, 1, get rid of some DC in your mains line or 2, get a better transformer...

Keep up with the good work Nick

I�m happy to have answered a few questions about what linear PSUs can do, but the results do beg some more questions.

1. Will the 861v4 benefit from a linear PS? I plan to find out shortly; though I don�t foresee having access to a v6.
2. The G61 & G68 don�t have a separate PSU filter board, so would they benefit from an LPS even more than the 861?
3. Do the G-series units have different secondary supply requirements to the 861?
4. Are the improvements confined to the analogue outputs, or are the digital outputs better as well?
5. Does this also apply to players, or for that matter, the HD621?
6. The self-contained solution has advantages, but would a separate supply be better?
7. What is the actual power consumption of the LPS?
8. Are there are any differences between commercial linear supplies?
9. Is there any benefit in going for an over-the-top PSU, like Naim?
10. Re: digital outputs, I don�t have any DSP speakers to play with, but I plan to put that right shortly.

Nick

Can you tell what are the internal dimensions of the free space at the rear of the G68?
That would be really useful, and I'll update my big spreadsheet as I get more information.
I'll do it myself if I can get my hands on another G68 & see if I can find what would fit inside.

Nick

Nick,

Congrats on the success of the power supply upgrade. I also greatly enjoyed reading your processor comparison thread on avforums.com.

MJT

Congratulations Nick

I can only imagine the fear when switching it on for the first time! Now try adding a mains regenerator to feed the unit, you'll find the acoustic presentation now more sensitive to changes in cables and supply. From my own experience I can recommend the PS Audio PPP with Wireworld silver shielded cables on the feed side. I also recommend changing over to European Schuko plugs and sockets, you'll see...

Bravo!

Steve

Hi Nick
I am relatively new to this forum and have followed this thread with great interest.

You appear to have hinted to a non techie a few fundamental truths:
1 Power supply technology really matters
2 "M" have moved from a technology driven company to a cost/profit driven company (understandable to a degree)but nothing new here.
3 I have attended demos of current "M" products and left feeling slightly underwhelmed, nice but... especially when one considers the evidence of diminishing returns.
4 500 series products feature LPS's and "Musicality" IMHO is the result.

Many thanks for the risks you have taken and the thought and effort that has gone into this project.

Your efforts tend to confirm that which I instinctively knew but could not put into words. Your defining of improvements are thought provoking and will be extremely valuable in influencing future upgrade decisions.

Your wish is my command - I hope this didn't take too long. Since I heard the V2 LPS, modding the V4 was a no-brainer. I bought a Lambda HTD-1 off eBay (it arrived in hours!), and there's one left if someone in the UK fancies a go. I found that the R3 Technology cover fits nicely if you drill a couple of holes.



I'm going to do this a bit differently - rubber grommet mountings, and I'll solder the DC output leads and put tags on the AC input leads instead. That means there's no need to remove the backplane or the front panel to remove the power supply. I'll let you know how it sounds. I've also bought an Acopian supply to play with - that should fit in a G68 if can get hold of one.

Nick