My experience is different. With a good phono preamp like the Aesthetix Io, I prefer a direct connection, no SUT. Although my testing has been limited. It has involved carts in the .25 - .60 mV output range. With a tube phono preamp there will be some noise, and a SUT may be useful for a low output cart, but so far, I have been better served without it (running a .55 ouptut cart, the tube noise is manageable). The SUT, in my case, gave a more beefy and gratifying performance at first sight, but I soon noticed that the phono preamp on its own had more clarity.
SUT or phono stage?
I have a new Rega P8 turntable on order complete with the lomc Alpheta 2 cartridge. Right now my main turntable is a restored Thorens TD 124 with an SME arm and an AT Art 9 cartridge. My Thorens is running through my McIntosh MC 47 preamp into the MC section and it sounds really nice. I’m going to have two tables hooked up to my system shortly and would like some advice whether I should get a separate phono pre or use an sut into the MM section of my McIntosh preamp. The phono section of my preamp has really good reviews and I can state the the MC section sounds good. I don’t have any experience with a SUT so it would be nice to have some thoughts from those who do. I do have a Vista Audio preamp that’s not bad also.