DACs That Improve The Sound of the Sony HAP-Z1ES

Some discussions of this here in the past, but mostly ad hoc rather than anything comprehensive.  For those using a DAC that both improves the sound of and works seamlessly with the Sony, I would appreciate your input as to what your are using, and if enough of a positive change to justify the expense. And even though every now and then I think about it, in the end would prefer to not move to computer based solutions, love the simplicity of the Sony.
Hi Anwar, thanks for the response and detailing of the various  iterations you have gone through.  Although I hope that your last sentence is not true, the lack of response here may be telling.  That Innuos Zenith gets a lot of good press, may be time for me to start looking at that and similar solutions, though I’m getting to be an old geezer whose patience wears thin pretty quickly these days so ‘simplicity’ is a priority. Good luck with your PC-based efforts.......
I have a Sony hap-z1es too. Placed a order for a innuos zenith  Mkiii.

looking forward to a big upgrade. Also just purchased a Weiss DAC501.  What a upgrade. I was amazed at what a outboard quality DAC could do for me.
Very nice Bike, wish I could afford one of those Weiss DAC's, bet it sounds awesome and then some!  Thanks for the input.....