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

Crion, was that meant to be a forum thread? It looked like a page on the Bursen website. I did see this discussion of "super" regulators recently, but I'm sure there are many more.

There are lots of things that power supplies and regulators need to get right, and it looks like some are successful at some things, but not others. Things like:

voltage regulation
ripple rejection
load variation
supply variation
output impedance
noise
bandwidth
drop-out voltage

Nick

By way of contrast to the Meridian approach, I stumbled accross this link on another forum. It shows the extremes that Esoteric go to with their new P-02/D-02 combo. The transport and the DAC each have four independant toroidal transformer supplies. In the transport, the master audio clock even has its own dedicated supply.

Nick

Bravo! I think that each manufacturer has their own area of expertise... Meticulous attention to power supplies has never been Meridians way.

There are improvements to be made, their first admission is changing the power supply to linear for the Anniversary models. But, maybe the typical Meridian client�le doesn't care for the finer details, simply a multi room set up that sounds just fine is sufficient.

For me the most important factor is that limitation is acknowledged - the be all and end all is not simply a Meridian set up, but in taking the route of Meridian you accept the compromised that are imposed and that you are content to live with them.

I have electrostatic speakers that are certainly not in line with the M philosophy. It doesn't mean that I understand nothing because I don't have the 8k's, it just means that I'm seeking an alternative path that is equally as justified.

Each to their own... this is the pleasure of hi-fi

My NMC 905 arrived yesterday.

Peter

Great to hear that - please let us know how you get on.

And thanks for the tip on the FG Elektroniks supplies in the first place. Anything I can do to help, please let me know.

Nick

Thought I would add my PSU upgrade experience to this thread...

I have a G68 with a variety of mods, including a modded PSU. I hired a local modder to do the work. He started with a Condor SMPS and added new caps and rectifier. The results were increased resolution, decreased high frequency harshness, and better dynamics.

He also changed the clock and the op amps, so strictly speaking, I can't say how much of the improvement was attributable to the new PSU. But the overall effect was a dramatic improvement.

Here are the G68 Modified PSU Photos

Bryon

Hi WelwynNick,

what's your state of play?

I have connected the NMC 905 provisional. It sounds great for five minutes, then it gets very hot (5V side), also in standby. The G68 seems to be a Class A preamp?
We need to find the cause of the large power consumption (5V) and fight it? Cooling the linear power supply more is IMHO the wrong way.

Peter

Sorry for the slow progress lately. All four PCs at home stopped working as Christmas approached, and I've been struggling to get them going again. If you're reading this it means that I've succeeded.

I have actually been putting a lot of time into the C61R linear PSU, but most of the work is finding the small bits and doing the mechanical work. The electrical connections could hardly have been easier - cut the old connectors off, strip the ends, and screw them into the FG connector blocks. Its very neat and it all works.

As you can see, I've turned the PSU upside-down and screwed the heatsink into the controller chassis - there's a bit of thermal paste squeezed out the edge of the heatsink. The effect of this is to create a more efficient heatsink, and the whole thing runs cooler now. I wouldn't like to guess the before and after temperatures, but I probably ought to try using some temperature tape.

However, because of the mechanical coupling, it runs noisier than before, and for the G68, I think I would prefer to use a larger supply that's running well inside its capacity. My experience so far is that they run cooler and quieter.

I suspect that a large supply under low load has low ripple as well. I tried running a few simulations, and other things being equal, a large rectifier capacitor allows you to use a secondary voltage close to the regulated output. In other words the ripple doesn't fall below the wanted voltage. I think this means a relatively smaller load will cause a smaller ripple ahead of the regulator, giving the latter an easy time. So whatever the reg's supply variation is, a larger supply will give a lower ripple. So the bigger the better, a la Naim.

Here's a few pictures of the FG 905 installation.











Nick

Great work again Nick. Your tenacity in seeing this through is truly impressive.

You're doing such an in-depth job across the processor range that it looks likely that the vast majority of 'Hikers could benefit from your findings, should they so choose!

Cheers

George

Quick Update. I used to own a G68J, but I sold it rather quickly in hindsight, and didn't make the most of the opportunity to see what I could do with it. I'm modifying other HH'ers gear now, so further opportunities are presenting themselves again. I'm working on another G68J, and it isn't quite as straightforward as I thought. There's lots of space - enough for the PSU & amp for many receivers, so I wanted to fit something more generous than the FG NMC-305. Unfortunately, the cooling fan and the motherboard supports get in the way of the obvious choices like the generic HCBB-75W and CP-498 supplies, so I did a trial fit with the HDBB-105W. The big 5V smoothing cap fouled the fan, so I moved the cap from the base to the side, and look what happened:



I have a couple of other things to try, and I'm pretty sure the FG NMC-105 would do a good job, but in the meantime I'm pleased that the new 818 has a linear supply as well. Roll-on the 861v8!

Nick

Nick,

I'm being unbelievably stupid. Can't see anything particular in your picture. What did happen?

That is one mother of a PSU, How exciting.