Need tips to better my sound



I’m not computer savvy and enjoy the convenience of streaming.
Right now my router goes to my smart TV by ethernet cable. I stream Spotify app on TV through an optical cable to my dac (old parasound zdac) to yamaha integrated(a-s500) to Revel tower speakers.
Would the best Improvement be to get a dedicated streamer such as a blue sound? I heard blue sound doesn’t work with Spotify but maybe I could get Tidal? I have music stored on an external hard drive, but my computer is slow, old and crappy. I enjoy streaming and seeing my music choices on my TV screen. Do I need a computer to utilize a dedicated streamer? I don’t know how to go about improving this budget (ghetto) set up that I’ve got. The only brick-and-mortar store around me either wants to sell me tons of crap  I can’t afford, or Best Buy tells me "sonos".
suggestions? directions? thanks.
128x128labguy
I like my Bluesound Node2i, does a great job with a good amp and speakers, I’m not sure spending four times the price for a Lumin etc would deliver four times the improvement or an improvement to justify the spend, order direct and get an home trial. 
You guys rock! Thanks to everybody that responded. I see a recurring theme of suggestions for the next best step to take. High quality streaming with a dedicated streamer. I'm still not sure how or why that dedicated streamer makes a difference (wish I understood that) but I trust that it will. As far as Millercarbon suggestions, I'm sure in a well-established system, tweaks can customize and benefit an individual, but I'm looking to eliminate the weakest link in the chain right now, and as little as I know, I can say with relative confidence that it's not a fuse or power cord. The power cord for my integrated is built in, I don't see any fuse on it externally. My DAC is old enough that technology has probably advanced more than a power cord would change the sound, etc.  So I'll hold off on tweeks till a later time. The only other question that I have at this point would be other streamers to consider besides the bluesound node 2i. My Revel speaker dips down to 4 Ohms so don't need an amp built into the streamer because I'll require a dedicated integrated or amp. And if the streamer I purchase has a DAC, it needs to be better than the parasound Z DAC or I'm paying for a feature I won't use. If it is better than the Parasound ZDAC then I can at least sell my Zdac for a few bucks to offset the cost of upgrading the streamer / DAC combo. Thoughts?
First let’s clearly call out the fuse recommendation as totally baseless other than that there are some obsessed with fuses here for whatever reason.

Then realize Spotify sound quality is not bad but is not even CD resolution so that is a clear compromise. Tidal Amazon HD or Qobuz is better.

Having been streaming now for many years I find differences in streamers to be minimal in general however DACs make a big difference similar in magnitude to cartridges playing records.  If you have an older DAC in particular I would look to upgrade there first.