1Z and TA-ZH1ES are substantially different when using the same cables silver-gold and 4.4mm into Utopia. I use my DIY cables. The separation, soundstage is much wider, taller and in a better rendering with much more vivid resolution on Ta-ZH1ES. The body has a denser energy. It is as much of a different as that if I was to compare A/B between WM1Z+Utopia or TA-ZH1ES + Utopia, I would immediately reach out for Ta-ZH1ES whenever I can. However, as I leave my TA in the office, the WM1Z and Utopia is also very satisfying to take home with as well.
I did not try Utopia with the best silver wires cables yet. I briefly tried it with some older Silver wires I had here, but it is a PITA to work on the cables and expensive Lemo is not ideal to make different cables to A/B. I only briefly compared it from memory. Basically the silver-gold has better Bass body while still retaining the speed, splashes and sparkles of the trebles.