Advantages with an outboard power supply

— and another - LHY. Sold under the Jays Audio umbrella. Look to be well built and reasonably priced. I’m sending an inquiry for what model/voltage is recommended for the RME.

I had a Teddy Pardo with a RME ADI 2fs. I just traded it in towards a PSA DS MK1, so we’ll see how that goes. I picked up a PSA AirLens and want to go with is I2S connection which the RME doesn’t  have. Also wanted the flexibility of more inputs.

Back to the Teddy Pardo. What it added was essentially more of everything but if I had to start it would be weight and authority; going back to the stock switch supply, the RME seems a little thin and not as involving. I also ran a Synergistic Orange fuse in the Teddy which smoothed things out a little. I used a WyWires Silver Juice II Digital Series power cable which elevated the combo as well. In short you will not be disappointed with adding a Teddy Pardo LPS. I don’t remember what specific model I had, but the people at Teddy Pardo know so no worries. They were very easy to work with and coming from Israel I received within a couple weeks from ordering. Highly recommended. 

My set should be showing up on The Music Room so no idea if they keep it as a set or separate and pull the fuse out and sell separately. They just received so it’s not on their site yet, but I would think you could call or email them if interested.

Looking at several power supply options I ordered an LHY from TEK Electronics who rep Jays Audio. I also ordered a Sablon USB cable both of which should be here late next week. 

The external LHY LPS for the Bluesound N130 makes a difference to my ears.

I don't believe anyone has answered your question. Then again, it has been covered many times. The power supply is the heart of any audio component. In recent years, switching wall-wart power supplies have become popular because they work very well and cost the manufacturer a tiny fraction of a robust linear power supply. The power supply in theory isolates everything that comes after it in the circuit from RFI, EMI, DC, and dirty power "hash". It also, when well-designed and implemented, provides for dynamics, authoritativeness, propulsion, etc. 

The more expensive a component is, the more likely it is that it will have a robust power supply. Switching PS's are a cost cutting measure, virtually always. Generally speaking, an outboard PS that connects with a thin wire and 6mm pin is not going to be optimum. An outboard PS has great advantages in terms of avoiding transformer induced noise spuriae, usually at 60 hz in the US, but only if connected with a beefy and well designed umbilical connection. The Manley Steelhead phono stage is a good example. 

For better or worse, there is once again a lot of intellectually honest debate on this subject. One camp insists that if any component, including a DA, is a featherweight, it is bound to be lacking in the above qualities. Again to be clear, this applies to pre-amps, amps, phono stages and DAC's. When it comes to very high end DAC's, it is rare to find the lightweights but they are out there. Chord is one example. Benchmark is another.