I have always found a linear power to be an improvement over a switching power supply. This is both in analog sources/preamp as well as digital transport sources. If your system is very warm and laid back, you may not notice any difference. I think your Plinius integrated is going to be a much higher resolution and revealing amp. Upgrading your phono stage to linear power supply will likely remove some glare from the sound and give you a smoother and more realistic sound. I took a look at the
Sutherland Insight phono stage. The power supply is a separate board that can easily be taken out and replaced. If you google for picture of "Sutherland Loco", you can see what the linear power supply board looks like. They would use the same one in your Sutherland Insight phono stage.
How important is a Linear Power Supply Versus a Switcyed one?
I recently purchased a used Sutherland Insight phono stage to replace the built in one in my Plinius8200 MK II integrates amp. I was amazed at the improvement in openness and presence. It comes with a switched power supply but there is an option for a Linear Supply for about 35% of what I paid for the Insight ($350). I have a Van den Hul One Special cartridge (if that matters). Is it worth it?