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

A very valid argument. My system is without FIFO, relying on mathematics and upsampling to try and minimise the effects of induced jitter. Whilst my system does not utilise a traditional DAC, the digital circuitry within is source clock dependent

Both are band aids however, and ultimately a system devoid of the errors in the first place should prove to be superior (although may prove to be completely impractical)

"Bear in mind that SpeakerLink was simply to meet a requirement from the custom install market to be able to utilize in-wall RJ45 cabling. Meridian didn't expect it to sound better than SPDIF - they put down any improvement to the improved encoding and decoding circuitry at either end of the link."

Given the sensitivity of present owners, would it be realistic for M to concede publicly that their original single ended digital links were inferior?

Either way, the new symmetrical "balanced" SL arrangement should be technically superior and if that also keeps the installers happy then that's great too win-win!

Agree with everything you wrote. Sony, Tag Mclaren and Arcam also had proprietary digital audio interfaces that got it right, but none were standardised. There are a few other interfaces that achieve something similar though.

Sony i-link used flow control on a firewire connection to achieve what amounts to a DAC-master config, though its not synchronous (not sure if that really matters).

HDMI has a similar cabability confusingly called ARC (audio rate control: not audio return channel!) but only Ayre has implemented that properly (DX-5), while Sony & Pioneer have introduced proprietary implementations (idiots).

USB has an asynchronous mode that is becoming increasingly popular (google Gordon Rankin streamlength - what a hero).

Nick

To put this into perspective, the acoustic interaction between the loudspeakers and the listening room will have a far greater influence over the final presentation than either of the above considerations.

However, in the pursuit of excellence (that I assume we all allude to) everything matters...

Hi Nick,

Your findings with the g61 sounds very interesting.

I would very much like to buy a linear supply for my G68 - could you perhaps help me out ?

(PMs are welcome)

I�m glad someone else is enthusiastic about taking the LPS route � I really want other people to hear what I�ve heard. Can�t keep this to myself.

For the G61, it may be possible to use a Condor or Power One HTAA-16W. However, I�d probably recommend the more powerful FG Elektronik NMC 905 instead, even though it doesn�t have over-volt protection or adjustable output.

So far I�ve only used a big Power One supply externally with the C61, but I have bought an NMC 905 to fit internally. That should be arriving soon, so watch this space. I hope to fit that at the weekend, and give the thumbs-up.

Nick

Nick - if the input filter/fuse/switch can be upgraded/redesigned then I can't see why the SMPS shouldn't be retained for the digital and control circuits.

Use the separate (and isolated) analogue linear PSU for the analogue circuits but you must be aware of the new grounding requirements, I guess you'd need a schematic

Nick - Re the 905 http://www.produktinfo.conrad.com/d...0167-da-01-en-LINEARE_STROMV_NMC_902.pdf

Which regulators are used onboard - LM317?

I was particularly keen to use linear supplies for everything, not just the analogue stages. Triple-output linear PSUs typically have the 5V and the +/-12V supplies isolated anyway - always with different secondaries, and often with separate boards. When I install them I keep the 5V and the +/-12V returns separate as well. I wouldn't consider using a switching supply just for the digital circuits.

Edit - indeed, if I ever get another HD621, I would certainly fit an FG 305 linear PSU. I'm confident it would improve the jitter performance.

One option I did consider was having TWO linear supplies: one for +5V and another for +/-12V. That might help isolation, and maybe optimise the volume / power capacity balence for smaller spaces. Where there is space though, like in the 861 and G68, I'd just go for a big single supply.
All I know is what's on the datasheet - looks like LM7812/7912. I don't think there's anything special about the 905: the performance is par for the course, and no more. I suggested it because of the combination of 5V current capacity, and the form factor. Within the FG range, its the 105 that's the one to go for if you have the space (like the G68).

Nick

I'm really sorry... http://www.belleson.com/compare7812.php - it'll drive you nuts in the end

Looking forward to hearing more after the weekend then - if it all works out, I hope you will guide me through the steps :o)

Thanks (I think). There's an interesting recent thread on the Belleson regulators at DIYAudio (great site). There was some probing scepticism about the test results Belleson gave, and one of their gurus worked through the issues in a professional and convincing way. I think the end result was the performance of the superregulator was generally accepted to be even better than Belleson had originally been claiming. There are lots of high-performing regulators out there, but the Belleson sounds like the one to have.

This made me look closer at the FG Elektronik supplies. Apart from the NMC 102 and the ultra-linear modules, they're nothing special, and might make a good platform for modification. They're attractive because of the combination of current/voltage capacity, and the physical form factor. Better regs will probably make them better, but to put things in perspective, a single Belleson super reg is more expensive than the whole Power One 105W supply that fills my 861V2, and transforms its performance. That doesn't mean the Bellesons aren't good value though

I'm confident that there's more performance to be had, but even the oldest and most basic linear supply is a huge improvement over any switching supply, both subjectively and objectively. The FG 905 supply has just arrived, which brightened an otherwise miserable day. Can't wait to get it in there.

Nick

OK, I couldn't wait until the weekend, and I think I've found the solution I've been after for some time.

I'm listening to the FG 905 powering the C61R right now, and it sounds great. Its also physically very quiet. I compared it with the 861V4 again, and my impressions were similar to using Power One supply. While I can't compare different linear supplies directly, I don't think I can hear any difference attributable to the supply itself. Which, considering its low lost and small size, means the FG supply is quite a success.

The slimline C61 / G61 don't have much space inside, and I'd been wondering if that would stop me using an internal LPS, and the answer is no. The output voltages are spot-on, and apart from shortening one of the triangular plastic supporting brackets, the installation looks to be relatively easy. The FG's have screw connections for AC & DC, and that makes things much quicker and easier. If you cut the DC harness close to the SMPS connector, the wires will just about connect directly into the FG output blocks. Very neat.

I did a quick measurement, and if you wanted to be a bit more ambitious, it looks like the Belleson regulators would fit very neatly (though there are four of them!). The only possible qualification to all this is that the FG runs hotter than the Power One. You can still hold the heat sink after a few hours running, but the bigger supplies do run cooler.

So far, so good then. I'll keep playing over the weekend, but I'm happy with what I've seen. Really - everyone should do this.

Nick