Upgrade from iBasso D10

The DAC in the D10 is actually pretty good, and the ability to use it as a standalone DAC is a nice feature. 

But I wasn't overly impressed with the amp section when I had one.

Maybe get a desktop amp, then you can use the D10 as a DAC and still keep the D10 for more portable/transportable use.

The D10 should cope OK with both your phones power-wise, but a desktop amp would open up the possibility of more demanding phones in future.

I don't think either of your current phones need a lot of amping, but for me the D10s amp section seemed a little bright and thin to me so a different amp might improve your enjoyment - that said a different portable amp could do the same.

The benefit of a desktop is your options are much more open for the future. You won't keep hearing about phones that sound great only to be told your amp won't do them justice.

Since the D10 has a decent DAC, keeping the D10 for home use as a DAC and a portable option and investing in something more capable for home might be the best use of your funds.

Another option would be to get the opamp rolling kit or a topkit to change the sound of your D10.

The D10 comes with an opamp rolling kit, and it does get less bright and less thin with alternate options - but still bright and still thin. If it is down to the opamps alone and not other less changeable elements of the circuit then maybe it could be amazing, if I had the patience maybe I would have kept trying rather than selling it on. Whatever the case - it will never be a replacement for a desktop amp.