Power Supply for Schiit Mani Phono Preamp

OK, so I looked up the Swagman supply for the Mani. It is not a linear power supply, it is a transformer (16 VAC, 2 amps) with a ferrite EMI suppressor and the correct plug to fit the Mani. I agree it will work perfectly and maybe sound better due to the increase amperage.  However, may I recommend you try the Floor wart from Schiit at $24.It is 14 VAC and 1.5 amps. If you like you can add a $2 ferrite clamp.

I went to the Schiit website to look into the Mani.The wal-wart is specified as a transformer with 16 VAC output.The chassis shows the input should be 16 VAC.The FAQ says the power supply is linear.The photo of the circuit board shows a diode bridge and filter caps near the power switch, confirming the PS is linear.
If you were to plug an external linear power supply into the Mani, it would be a bad thing for the Mani and the lps. ( It would void both warranties.) It can't possibly improve the sound.

I have no problem with the possibility that the Swagman transformer could sound better than the Schiit walwart transformer. But several people (including yourself) were referring to it as an LPS, which it is not. This is fortunate in that the DC output from a LPS into the circuit board  of the Schiit Mani would be a problem.

On The Swagman site he describes it as a toroidal transformer with some sort of EMI treatment. the spec on the site is an output of 16VAC, 2A (which is a clue that it is only a transformer). A transformer converts 120v to some other AC voltage ( it cannot output DC). He does call it a power supply which is stretching it a bit.A linear power supply starts with a transformer, then a rectifier/diode bridge, then a filter capacitor system, possibly also inductors, and finally a voltage regulator for each rail. It will output a specified DC voltage.Schiit uses an external transformer in a walwart package for reasons of cost and to use a smaller chassis which  is more convenient for an entry level user. The rest of the linear power supply is on their circuit board. They provide a really high performance to cost ratio product. I cannot name a used phono preamp for less that $300 which might be as good.
Using the Swagman transformer to replace the external walwart, the AC voltage goes through rest of the linear power supply on the Schiit circuit board. The current that this linear power supply can provide is limited by the rating of the rectifier, which might be only 1 amp, since the Mani only draws 4W. (This means that using an even higher amperage transformer would not be an advantage).
If you were to input a DC voltage into the Mani, the diodes might let the voltage flow to create either a plus or a minus 5V rail ( depending on how the polarity on the plug happens to be) but not both. Not a good thing.I suggest you do an internet search for "linear power supply".
I am not an EE, but I can solder and read a schematic, and have built a linear power supply from Radio Shack parts many years ago. BTW, to build a Swagman "power supply", would have a parts cost of ~$70 if you use good parts, so his product is not a ripoff.