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

I've been very busy fitting an HDBB-105W to the G68 for another HH'er. It was a squeeze, but it does fit:





The nuts that secure the fan are close to clashing with the PSU 5V capacitor, capacitor clamp, capacitor bracket screws, secondary wiring, and the PSU chassis.

The capacitor is close to the PSU chassis and PCB, and the mounting screws are close to the edge of the chassis.

The PSU mountings are close to the walls of the controller and the main board brackets.

The PSU chassis is close to the display PCB.

The transformer is sandwiched between the fan and the lid of the controller .

Apart from that everything fits fine once I lifted the PSU 26mm off the floor and moved the high-current smoothing capacitor into a corner.

That was a sqeeze....

Nick

And here's the end result:



It took me a while, but its up and running now. It's a snug fit to say the least, but its running cool and quiet. I'm listening to some Tori Amos at the moment, and it sounds like a different recording. I really like these old supplies. This installation retains all the existing input, output, earth and fan connections, plus the main PCB supports. I'm happy with this because all the electrical and mechanical interfaces are accessible from above with the PSU in situ, and the PSU can be removed and installed without having to remove anything else. Fitting the slightly smaller CP-498 supply would be easier, but I'm pleased with this now. There's one thing that does stand out, though - the controller really is HEAVY!

Since KCLee mentioned that he took some temperature measurements of his linear PSU installation, I thought I should do the same, so I left mine running all day. Everything started off at ambient, 18oC, warmed-up over about two hours, and then stayed pretty much the same for a further ten hours:

Ambient: 18oC
Lid: 29oC
Heat sink: 38oC
Regulator: 42oC

The interesting thing is that after the same time running, the rest of the controller is running at similar temperatures as well. I recorded the temp of the card guide that holds the analogue output board. That warmed-up a bit more quickly than the PSU heat sink, and stablised at 38oC as well. That gives me a lot of confidence that the LPS installation will be safe and reliable.

Nick

Nick,
What is the power consumption now?
S.

270mA x 240V = 65W

Now here's a crazy idea:

ATX 2009 Corsair CX 400 Watts Corsair CX 400 Watts

Kingwin LZP-550 Lazer Platinum 550 W

Anandtech - Seasonic Platinum Series 860W - Platinum without the Fuss

PC power supplies aren't as good as regulated linear supplies, but the best of them aren't bad at all, and I wondered if I could fit a PC supply into a surround processor:



Its rather overkill, as processors & DACs only use a few tens of watts, but ripple is usually lowest at low load levels, and PC supplies are hardly expensive in the context of four-figure processors. Linear supplies are better, but they do generate more heat, and the transformers hum a bit, so now I'm wondering if a high-quality PC supply would improve on the stock supply (50 - 100 mV noise & ripple), while avoiding some of the noise, vibration and heat issues. A nice compromise in the middle, maybe?

Nick

How about a fanless variant. Lower power, less heat!

http://www.silentpcreview.com/Seasonic_X-400_Fanless_PSU

I put the fanless Seasonic power supply in my PC and it ran hotter than my previous Seasonic power supply that I had disconnected the fan on. A fanless PC power supply is not going to solve any heat problems.

I'm not sure I'd want to risk using a supply that didn't have any fan at all, but some of them keep the fan off until they're supply half power or somethign like that.

I think the deal with the fanless supplies is that they're very efficient - up to 90% efficiency, and have very low dissipation. They tend to be expensive, but have low ripple.

Whether the higher-frequency components of the ripple have any adverse effect on SQ remains to be seen.

Nick

I hear you. I would think that the draw on the power supply would be very minimal, likely allowing for a fanless supply.

Hi All, I haven't visited this thread for a while, but I was still shocked to see what the view counter was up to. Maybe there's a few more people ready to take the plunge....

While discussing fitting linear power supplies with other Hitchhikers, it seemed that certain practical considerations were important. We all want good sound quality, but there�s a limit to the size of the barriers we�re prepared to cross to get there. Modifying one�s own equipment is a barrier for many. Another barrier is the need to send a large, heavy, fragile and valuable of piece of equipment to a stranger, across the country, by a carrier that doesn�t care. Some prefer a side-by-side comparison before committing to a purchase. Perhaps the lack of reversibility or maintainability is another � there are several reasons for keeping the option to reinstate the original build. However, several HH�ers have replaced a failed SMPS with new one. This is a matter of a few screws and a couple of connectors � in other words, a drop-in replacement with minimal modifications.

So I wondered if something close to a drop-in linear PSU might be feasible. The electrical interfaces would be the same as the SMPS � AC input and DC output, plus a ground lead. Selection and fitting are tricky, but I now reckon the generic CP-498A is the ideal supply for both the G68 and 861. It�s cheap, powerful, cool, quiet, readily available, and fits easily. It�s probably the closest thing to a one-size-fits-all linear PSU, and I have a good option on a batch of new supplies.

So I�m considering offering CP-498�s adapted as far as possible to be drop-in replacements for the stock switch-mode supplies. These would have installation instructions, mounting brackets, and the same electrical connections as the stock supplies. I think this might overcome some of the barriers described above, and help a few more people to hear what I�ve been hearing.

I wanted to get some feedback from more Hitchhikers first.

Cheers, Nick

Sounds like a great idea NIck.

I would be interested in trying this.Sounds like a great idea/upgrade.

Phil..

Hi Nick,

I may have missed it, but did you or others reach any conclusions on whether there is a wortwhile sound quality improvement with DSP speakers? If so, I would certainly be interested in what you're proposing, for the G68J I bought from you...

Steve