The Topping D90 is a good DAC. It has a nice set of features if you already have a good Headphone amp. now if you do not have Headphone AMP, I would buy the RME ADI-2 DAC fs. Honestly, on high gain, I can run the Susvara, I still rather use an external headphone amp for them but in pinch it a great sounding. But for HE-1000se, Ananda, Arya, Rad -0, Focal headphones, it all you ever need.
I like the AKM based DACs I have a few them
- RME ADI-2 DAC fs - AKM4493 Still my favorite due to the feature set of the whole solution.
- Topping D90 AKM4499 -great DAC especially for the money
- Xduoo XD05 Plus ( nice portable AKM4493)
- SPL Phonitor X. with DAC192 aka AKM4490. ( came with the AMP)
But the other DAC I have in the arsenal is Chord Qutest and SCHIIT AUDIO Bifrost 2 also very good DACs.