Mac Mini Power Supply

I use Isolation transformers in my system that I modified to great benefit. I am yet to find a power conditioner that works better than the Isolation transformers. The ECM is a transformer-based conditioner. So I imagine it's decent. I just use hospital grade TXs made by Topaz, which are considerably better than the ECM (though bigger, heavier, and uglier).

I partially followed the datasheet for the LM338. I used a LM337 for the negative rail (which doesn't draw much current, I believe it's only duty is iSense).

I think just going from a switchmode supply to a linear supply would give a great benefit, I just wanted to take it a step further and put some decent parts in the supply.

There's a few regulators based on the LM317 that you can just do a parts swap (with a little research).

Before spending money on power supply or expensive power cord, please try the snap-on ferrite cores first to reduce digital noise. Just snap one on each end of all your power cables and digital cables. They are very effective and cheap.

Ferrite cores are a fairly standard trick. They are cheap and while they will filter out some noise, they are no replacement for a proper power supply IMO.

I personally don't like them because they greatly limit dynamics. I also found that the ferrite cores did very little when attached to the mac mini stock power supply.

You will also want a rather large ferrite core to make it effective. I have found that Neodymium magnets filter better than ferrite cores only they don't limit dynamics. Granted, I am still skeptical of magnets and am doing further tests to make sure I wasn't just hearing things.

"I have always found switchmode supplies to be VERY noisy and mechanical sounding."

I don't question your findings but I hope you realize that this voltage (is it 18V?) goes inside of Mac Mini thru internal switching regulators to deliver voltages for micro and rest of digital circuitry.

Linear powers supply is also a switcher operating at 120Hz. It takes current from mains in very narrow current spikes of big amplitude. Width of the spikes depends on the load.

Switchers got bad rap from cheap computer power supplies but realized properly are not only very quiet but also line and load regulated (class D is switching mode supply). High switching frequency is not audible and easy to filter out. For that reason Jeff Rowland uses switchers in Capri preamp.

Where would one find plans to build this psu and a parts list? I'm intrigued by this idea. Thanks Mintzar.