Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems New Linear G68 PSU from Nick - initial thoughts

Well, you may recall that my PSU died in my G68 - oh, and the G91 when I moved it to ship off the G68.

I am now the proud owner of the larger, considerably heavier, Linear PSU that Welwyn Nick went to great lengths to shoe horn into the G68J.



Nick has kindly lent me a replacement SMPS PSU to do a full A/B comparison, but I have to say that my initial reaction to the new PSU takes me back to the day that I first had Meridian installed at home! I was working from home today... the kids were at school and the wife off to a champagne lunch, so I took the opportunity to start from scratch with the M. install.

A new MConfig set up and even got around to a room correction. The MRC needs some tweaking as I've read the Wiki since and I need more filters, but can't work out how to set a lower target decay time.

I put on a couple of old favourite CDs (Savage Garden & Deacon Blue) as I know that the mastering on these is great. The results? even before I ran room correction (which seems to make very little difference at the moment):

Wow!

I heard backing vocals which I had previously thought were some kind of 'synth' or electric guitar. The bass was 'tight' and very detailed. I have never had my system sounding this good. Too good. To the point that whilst 'working from home' I had spent 4 hours of listening. Now I feel a slight (only very!) pang of guilt.

It feels like a brand new system.

I can't say for certain whether it is the PSU or the fact that I started from scratch with the configs, but there's nothing majorly different in my configs from original, so I can only come to the conclusion that the linear PSU has made a tremendous difference to my analogue set up.

The G68J is heavy! It makes an interesting warm up / switch on 'twang' which sounds magnetic, but it actually sounds reassuringly good. The unit runs warm - especially with the G91 on top, but not noticeably more so than before.

One interesting point to note was that when calibrating speakers, I needed to invert the phase of the centre speaker. I had never paid any attention to phase. The M. manual says that it's correct if you move your head around and the timbre doesn't change. When I tried it and moved my head, it becomes very obvious - almost nausious - when it is not correct.

I had the usual MRC SNR problem with the Sub, but I'll read up on that, but overall, my system has made me smile again today and it hasn't done that for a very long time!

My sincere thanks go out to Nick for his hard work, investigations and patience in exploring the various options.

As a point of interest, the G91 was displaying a problem where the DVD-Rom was 'hunting' at boot up and the unit would never boot up and settle. A direct swap out of the PSU (with a reversed pin out - good job I checked) resolved the problem.

I will report back once I carry out some PSU comparisons, but for now, I'm loving every minute and intend to enjoy that feeling for a while to come.

Regards
Pete

Big grats on your Anniversary G68J!

The more we hear about the importance of clean effortless power to our systems the more I believe that we will see more linear PSUs in the upcoming hardware refreshes.

Thats one hardcore G68J grats on new system hehe

Great stuff. So, with reports like this and the fact that M are using linear power supplies in the Anniversary stuff, it looks clear that it makes a difference. So, what is the theory behind the improvement and does it have much bearing on whether power conditioners/power cables are snake oil or not?

Cheers Tintin

Some benefit may be related to removing radiated pollution caused by high frequency switching and/or lower noise/ripple output characteristics compared to an average switch mode PSU.

Switch mode power supplies are small and noisy and are optimised for a particular load.

Linear power supplies are large and inefficient but are smooth and handle fluctuations in load easily.


SMPS = 1400cc turbo engine with a race cam producing 200hp

LPS = 3500cc NA V8 producing 200hp

In an all digital set up it could be argued that it shouldn't make much difference. G68XXV owners should be looking at this for an upgrade though.

All the best,

Steve.

Chord amplifiers seem to use switch mode power supplies quite successfully. They run relatively cool, provide excellent audio quality and are capable of delivering lots of power. I believe they are designed in-house rather than purchased off-the-shelf.

Any thoughts?

Whats the legal position as a manufacturer of supplying inefficient linear power supplies as part of their product lineup?

I haven't read the COMMISSION REGULATION (EC) No 1275/2008 in detail, but would the inclusion of a linear power supply by a manufacturer prevent them from achieving the stipulated 1W/2W standby or 'off' mode?

A mate of mine works for NPL who test some of these things and he told me of a refrigerator manufacturer whose device detected the 'test conditions' and put itself in a special low power mode just to satisfy the test, but not under normal working conditions.

No, my Arcam amp has a linear PSU and a <2W standby.

Duncan

Hi Pete,

I'm really glad you like it, and not to say a little relieved. I didn't want to believe I'd been imagining it all along, and I was keen for someone else to hear the difference a linear supply can make.

For everyone else's benefit, I fitted Pete's linear supply with the connectors from his failed SMPS, so the existing AC and DC cables just plug right in, much as they do with the stock supply. That allows the linear and switching supplies to switched over quickly and easily.

Its nothing to do with snake oil. Linear regulated supplies are measurably better. SMPS have 50-100mV noise and ripple one each line, and good linear supplies have 2-5mV. They also have much better load regulation and supply regulation as well. Although there ARE some SMPS that do have low noise and ripple, such as Datron Power, I still think linear supplies are cleaner. They operate at 50/60Hz, plus maybe a couple of harmonics, while switching supplies need to operate at high frequencies, and that gets everywhere you don't want it to.

Nick

I have modified my G68 with a Condor CP498A PSU using an external chassis, resulting in a much better SQ and more clear sound stage.

The modification is completely reversible. I have not drilled any hole and cut any cable in G68. A custom made small rear panel is installed to replace the original G68 power supply panel for directing the wires into the G68 chassis.

I found a high quality aluminum chassis to house the PSU and connect it with two custom made cable harnesses. The chassis is 2mm thick stain finished. The front panel is 6mm thick.

The operating temperature of G68 become cool, identical to the ambient temperature. The temperature of PSU chassis is about 20 deg C above ambient.

G68 external Linear PSU - Photos



KC Lee

Exceptional work!