Better DAC or better Streamer

Since the original questioner asked what would be the better upgrade, I believe it to be by any measure the DAVE DAC. It leaves some space for enjoyable experimentation to try a couple well regarded inexpensive streamers, some mid price and one or two "High End" ones. Hear for yourself via a resolving high quality DAC and make your own mind up.

I would just qualify the answer I gave as assuming you would be looking to use a standalone streamer with the DAVE, if not then of course, moving from a DAP to a decent streamer is the first option

DAC

No matter what you upgrade, DAC or streamer, you will get an improvement in sound quality. However in your case @eddy1 you will have a bottleneck in your streamer and you will be upgrading it soon after. The SP2000 is similar to streaming with iPad - there’s plenty of room for improvement there. 

Probably, since you’re asking, it is only a question of which you upgrade first.  I’d say go for the streamer first and then get that signal as clean as possible and if you’re still not happy, go for the DAC. I noticed a huge improvement when I went to a Grimm MU1, connected via Ethernet cable, with the cable running through DX Engineering ISO-PLUS Ethernet RF Filters and using Puron power filters in the same outlet as the router.  There was no audible difference between the MU1 and SACD.  The cool thing about Grimm’s DACs is that they give the ability to up sample to either 2x or 4x.  To my ears, it doesn’t get much better than the 4x up sampling.  Links to the filters are below:  

https://www.dxengineering.com/parts/dxe-iso-plus-2?srsltid=AfmBOoqNt2mAvvVq9e-uoloXY2x0rsNUwqENt5oeOX8jVwxFjIpgkZzL

https://positive-feedback.com/reviews/hardware-reviews/puron-ac-power-conditioner/

Happy listening! 

What are you looking to achieve with the upgrade?   Hard to make any recommendation without knowing.