A warm DAC?

Many of these threads can contain posts that ignore the OP’s question. Look at his request again. He clearly states his mission, his concerns and the equipment he has.
The major variables in this game are the listening room accoustics, desired audio levels, and the recordings played. And then there is the equipment. Like countless other audiophiles it sounds like the OP purchased quality efficient speakers and other components. Playing digital music can bring a of lot desired qualities to the table: big sound stage, clarity, speed, and detail. Digitally sourced audio can also be like a digital photograph that has too much sharpening added: at first glance at a distance it looks great, but a closer more focused look reveals an unnatural false graininess.
Some systems (even expensive ones) can sound wonderful at first, but longer listening periods bring fatigue and a desire to turn the volume down. The common quest is system matching to fix this. Focussing only on sine wave measurements without actual listening just makes this harder...

To the OP: you state your budget is $2500.

This DAC gets a lot of great attention from owners and pro reviewers. It fits your budget down to the penny.

https://www.audiomirror.com/product-page/tubadour-iii-se-nonoversampling-tube-dac-2500

I currently have a Linn Majik DSM in my second system. I am thinking about getting a Lumin U1 streamer and the Tubadour instead...

DACs have the front end where the chip/tubes resides plus the power supply, the analogue conversion circuit, the cables, the case, the various connectivity ports, the feet, etc, etc. All of this combines to produce “the sound” and level of quality. The balanced RCA might be very good on a DAC but the USB port could be of super cheap quality. It all matters. 
A cheap DAC might have a SS chip that measures well but the rest of the unit might be all cheap as possible components. The analog circuitry has a bigger influence on the sound signature than the chip. 

This is why many audiophiles will take their time doing careful listening. Everyone’s ears and level of focused listening will be different. If you look at Amir’s graph listing all the DACs he has measured you will see that there are a lot of DACs that have similar measurements but many of them have very different prices, connectivity options and sound signatures. Success in picking one will depend on the rest of your system, your room, your music and how you (and only you) prefer your sound. 

Fair point. But your determination (or mine) does not become the de-facto metric for everyone. 

I think in this audio arena the most useless term is “always”. I find that almost all absolutist statements can be countered with “it depends”. 
Folks in this hobby mix and match all manners of tube, solid state, Class A, Class D, etc, equipment in an infinite array of combinations and price points. Some are very casual and some approach this pursuit very intently. 
Some believe 100% in the “bits are bits” approach and never waiver from thinking that streamers, DACs, cables, different interconnects, power supplies, reckockers, isolation feet, racks, etc, etc, matter. Others think it all matters. 
In the end what counts is this: do you enjoy the music from your system? Are you ok with the money you have spent to get there? 
  

Then why do companies research, develop, market and successfully sell DACs that cost $2000, $5000, $10,000 or $80,000? Why do financially successful people buy them? Why do people who have spent time, effort, listening tests and lots of money on their speaker systems and amplification then spend more time and money auditioning different DACs with the specific goal of achieving a specific sound without unwanted issues? Why not just spend $150 and be happy?

I just spent months on all this myself. I visited five dealerships in a four hour radius, spent countless hours reading about the pros and cons of gear, and then auditioned a wide number of speakers, amps, pre amps, DACs, all in one streamers, etc. I took my time and LISTENED. Now pretty happy with my system. I might look at other DACs someday, but for now just going to rest a bit.

As the saying goes: your mileage may vary...

At times I feared this thread had drifted into the weeds with nothing  more than agenda filled rants. But when you distill all the contributions this is an excellent thread!

Why? The answer is the passion from all viewpoints. In a way this is what makes this hobby so fascinating. 
Cheers everyone!